CINXE.COM

<!doctype html><html lang="en-US" prefix="og: https://ogp.me/ns#"><head><meta charSet="utf-8"/><meta name="viewport" content="width=device-width,initial-scale=1"/><link rel="icon" href="https://developer.mozilla.org/favicon-48x48.bc390275e955dacb2e65.png"/><link rel="apple-touch-icon" href="https://developer.mozilla.org/apple-touch-icon.528534bba673c38049c2.png"/><meta name="theme-color" content="#ffffff"/><link rel="manifest" href="https://developer.mozilla.org/manifest.f42880861b394dd4dc9b.json"/><link rel="search" type="application/opensearchdescription+xml" href="/opensearch.xml" title="MDN Web Docs"/><title>Organizing your CSS - Learn web development | MDN</title><link rel="alternate" title="Organisieren Ihres CSS" href="https://developer.mozilla.org/de/docs/Learn/CSS/Building_blocks/Organizing" hrefLang="de"/><link rel="alternate" title="CSS の整理" href="https://developer.mozilla.org/ja/docs/Learn/CSS/Building_blocks/Organizing" hrefLang="ja"/><link rel="alternate" title="CSS 구성" href="https://developer.mozilla.org/ko/docs/Learn/CSS/Building_blocks/Organizing" hrefLang="ko"/><link rel="alternate" title="组织 CSS" href="https://developer.mozilla.org/zh-CN/docs/Learn/CSS/Building_blocks/Organizing" hrefLang="zh"/><link rel="alternate" title="Organizing your CSS" href="https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Organizing" hrefLang="en"/><link rel="preload" as="font" type="font/woff2" href="/static/media/Inter.var.c2fe3cb2b7c746f7966a.woff2" crossorigin=""/><link rel="alternate" type="application/rss+xml" title="MDN Blog RSS Feed" href="https://developer.mozilla.org/en-US/blog/rss.xml" hrefLang="en"/><meta name="description" content="This is the final part of our building blocks module, and as you can see there are many ways in which your exploration of CSS can continue from this point — but now you can go on to testing yourself with our assessments: the first one is linked below."/><meta property="og:url" content="https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Organizing"/><meta property="og:title" content="Organizing your CSS - Learn web development | MDN"/><meta property="og:type" content="website"/><meta property="og:locale" content="en_US"/><meta property="og:description" content="This is the final part of our building blocks module, and as you can see there are many ways in which your exploration of CSS can continue from this point — but now you can go on to testing yourself with our assessments: the first one is linked below."/><meta property="og:image" content="https://developer.mozilla.org/mdn-social-share.d893525a4fb5fb1f67a2.png"/><meta property="og:image:type" content="image/png"/><meta property="og:image:height" content="1080"/><meta property="og:image:width" content="1920"/><meta property="og:image:alt" content="The MDN Web Docs logo, featuring a blue accent color, displayed on a solid black background."/><meta property="og:site_name" content="MDN Web Docs"/><meta name="twitter:card" content="summary_large_image"/><meta name="twitter:creator" content="MozDevNet"/><link rel="canonical" href="https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Organizing"/><style media="print">.article-actions-container,.document-toc-container,.language-menu,.main-menu-toggle,.on-github,.page-footer,.place,.sidebar,.top-banner,.top-navigation-main,ul.prev-next{display:none!important}.main-page-content,.main-page-content pre{padding:2px}.main-page-content pre{border-left-width:2px}</style><script src="/static/js/gtag.js" defer=""></script><script defer="" src="/static/js/main.1b60bff1.js"></script><link href="/static/css/main.959b5ea9.css" rel="stylesheet"/></head><body><script>if(document.body.addEventListener("load",(t=>{t.target.classList.contains("interactive")&&t.target.setAttribute("data-readystate","complete")}),{capture:!0}),window&&document.documentElement){const t={light:"#ffffff",dark:"#1b1b1b"};try{const e=window.localStorage.getItem("theme");e&&(document.documentElement.className=e,document.documentElement.style.backgroundColor=t[e]);const o=window.localStorage.getItem("nop");o&&(document.documentElement.dataset.nop=o)}catch(t){console.warn("Unable to read theme from localStorage",t)}}</script><div id="root"><ul id="nav-access" class="a11y-nav"><li><a id="skip-main" href="#content">Skip to main content</a></li><li><a id="skip-search" href="#top-nav-search-input">Skip to search</a></li><li><a id="skip-select-language" href="#languages-switcher-button">Skip to select language</a></li></ul><div class="page-wrapper category-css document-page"><div class="top-banner loading"><section class="place top container"></section></div><div class="sticky-header-container"><header class="top-navigation "><div class="container "><div class="top-navigation-wrap"><a href="/en-US/" class="logo" aria-label="MDN homepage"><svg id="mdn-docs-logo" xmlns="http://www.w3.org/2000/svg" x="0" y="0" viewBox="0 0 694.9 104.4" style="enable-background:new 0 0 694.9 104.4" xml:space="preserve" role="img"><title>MDN Web Docs</title><path d="M40.3 0 11.7 92.1H0L28.5 0h11.8zm10.4 0v92.1H40.3V0h10.4zM91 0 62.5 92.1H50.8L79.3 0H91zm10.4 0v92.1H91V0h10.4z" class="logo-m"></path><path d="M627.9 95.6h67v8.8h-67v-8.8z" class="logo-_"></path><path d="M367 42h-4l-10.7 30.8h-5.5l-10.8-26h-.4l-10.5 26h-5.2L308.7 42h-3.8v-5.6H323V42h-6.5l6.8 20.4h.4l10.3-26h4.7l11.2 26h.5l5.7-20.3h-6.2v-5.6H367V42zm34.9 20c-.4 3.2-2 5.9-4.7 8.2-2.8 2.3-6.5 3.4-11.3 3.4-5.4 0-9.7-1.6-13.1-4.7-3.3-3.2-5-7.7-5-13.7 0-5.7 1.6-10.3 4.7-14s7.4-5.5 12.9-5.5c5.1 0 9.1 1.6 11.9 4.7s4.3 6.9 4.3 11.3c0 1.5-.2 3-.5 4.7h-25.6c.3 7.7 4 11.6 10.9 11.6 2.9 0 5.1-.7 6.5-2 1.5-1.4 2.5-3 3-4.9l6 .9zM394 51.3c.2-2.4-.4-4.7-1.8-6.9s-3.8-3.3-7-3.3c-3.1 0-5.3 1-6.9 3-1.5 2-2.5 4.4-2.8 7.2H394zm51 2.4c0 5-1.3 9.5-4 13.7s-6.9 6.2-12.7 6.2c-6 0-10.3-2.2-12.7-6.7-.1.4-.2 1.4-.4 2.9s-.3 2.5-.4 2.9h-7.3c.3-1.7.6-3.5.8-5.3.3-1.8.4-3.7.4-5.5V22.3h-6v-5.6H416v27c1.1-2.2 2.7-4.1 4.7-5.7 2-1.6 4.8-2.4 8.4-2.4 4.6 0 8.4 1.6 11.4 4.7 3 3.2 4.5 7.6 4.5 13.4zm-7.7.6c0-4.2-1-7.4-3-9.5-2-2.2-4.4-3.3-7.4-3.3-3.4 0-6 1.2-8 3.7-1.9 2.4-2.9 5-3 7.7V57c0 3 1 5.6 3 7.7s4.5 3.1 7.6 3.1c3.6 0 6.3-1.3 8.1-3.9 1.8-2.7 2.7-5.9 2.7-9.6zm69.2 18.5h-13.2v-7.2c-1.2 2.2-2.8 4.1-4.9 5.6-2.1 1.6-4.8 2.4-8.3 2.4-4.8 0-8.7-1.6-11.6-4.9-2.9-3.2-4.3-7.7-4.3-13.3 0-5 1.3-9.6 4-13.7 2.6-4.1 6.9-6.2 12.8-6.2 5.7 0 9.8 2.2 12.3 6.5V22.3h-8.6v-5.6h15.8v50.6h6v5.5zM493.2 56v-4.4c-.1-3-1.2-5.5-3.2-7.3s-4.4-2.8-7.2-2.8c-3.6 0-6.3 1.3-8.2 3.9-1.9 2.6-2.8 5.8-2.8 9.6 0 4.1 1 7.3 3 9.5s4.5 3.3 7.4 3.3c3.2 0 5.8-1.3 7.8-3.8 2.1-2.6 3.1-5.3 3.2-8zm53.1-1.4c0 5.6-1.8 10.2-5.3 13.7s-8.2 5.3-13.9 5.3-10.1-1.7-13.4-5.1c-3.3-3.4-5-7.9-5-13.5 0-5.3 1.6-9.9 4.7-13.7 3.2-3.8 7.9-5.7 14.2-5.7s11 1.9 14.1 5.7c3 3.7 4.6 8.1 4.6 13.3zm-7.7-.2c0-4-1-7.2-3-9.5s-4.8-3.5-8.2-3.5c-3.6 0-6.4 1.2-8.3 3.7s-2.9 5.6-2.9 9.5c0 3.7.9 6.8 2.8 9.4 1.9 2.6 4.6 3.9 8.3 3.9 3.6 0 6.4-1.3 8.4-3.8 1.9-2.6 2.9-5.8 2.9-9.7zm45 5.8c-.4 3.2-1.9 6.3-4.4 9.1-2.5 2.9-6.4 4.3-11.8 4.3-5.2 0-9.4-1.6-12.6-4.8-3.2-3.2-4.8-7.7-4.8-13.7 0-5.5 1.6-10.1 4.7-13.9 3.2-3.8 7.6-5.7 13.2-5.7 2.3 0 4.6.3 6.7.8 2.2.5 4.2 1.5 6.2 2.9l1.5 9.5-5.9.7-1.3-6.1c-2.1-1.2-4.5-1.8-7.2-1.8-3.5 0-6.1 1.2-7.7 3.7-1.7 2.5-2.5 5.7-2.5 9.6 0 4.1.9 7.3 2.7 9.5 1.8 2.3 4.4 3.4 7.8 3.4 5.2 0 8.2-2.9 9.2-8.8l6.2 1.3zm34.7 1.9c0 3.6-1.5 6.5-4.6 8.5s-7 3-11.7 3c-5.7 0-10.6-1.2-14.6-3.6l1.2-8.8 5.7.6-.2 4.7c1.1.5 2.3.9 3.6 1.1s2.6.3 3.9.3c2.4 0 4.5-.4 6.5-1.3 1.9-.9 2.9-2.2 2.9-4.1 0-1.8-.8-3.1-2.3-3.8s-3.5-1.3-5.8-1.7-4.6-.9-6.9-1.4c-2.3-.6-4.2-1.6-5.7-2.9-1.6-1.4-2.3-3.5-2.3-6.3 0-4.1 1.5-6.9 4.6-8.5s6.4-2.4 9.9-2.4c2.6 0 5 .3 7.2.9 2.2.6 4.3 1.4 6.1 2.4l.8 8.8-5.8.7-.8-5.7c-2.3-1-4.7-1.6-7.2-1.6-2.1 0-3.7.4-5.1 1.1-1.3.8-2 2-2 3.8 0 1.7.8 2.9 2.3 3.6 1.5.7 3.4 1.2 5.7 1.6 2.2.4 4.5.8 6.7 1.4 2.2.6 4.1 1.6 5.7 3 1.4 1.6 2.2 3.7 2.2 6.6zM197.6 73.2h-17.1v-5.5h3.8V51.9c0-3.7-.7-6.3-2.1-7.9-1.4-1.6-3.3-2.3-5.7-2.3-3.2 0-5.6 1.1-7.2 3.4s-2.4 4.6-2.5 6.9v15.6h6v5.5h-17.1v-5.5h3.8V51.9c0-3.8-.7-6.4-2.1-7.9-1.4-1.5-3.3-2.3-5.6-2.3-3.2 0-5.5 1.1-7.2 3.3-1.6 2.2-2.4 4.5-2.5 6.9v15.8h6.9v5.5h-20.2v-5.5h6V42.4h-6.1v-5.6h13.4v6.4c1.2-2.1 2.7-3.8 4.7-5.2 2-1.3 4.4-2 7.3-2s5.3.7 7.5 2.1c2.2 1.4 3.7 3.5 4.5 6.4 1.1-2.5 2.7-4.5 4.9-6.1s4.8-2.4 7.9-2.4c3.5 0 6.5 1.1 8.9 3.3s3.7 5.6 3.7 10.2v18.2h6.1v5.5zm42.5 0h-13.2V66c-1.2 2.2-2.8 4.1-4.9 5.6-2.1 1.6-4.8 2.4-8.3 2.4-4.8 0-8.7-1.6-11.6-4.9-2.9-3.2-4.3-7.7-4.3-13.3 0-5 1.3-9.6 4-13.7 2.6-4.1 6.9-6.2 12.8-6.2s9.8 2.2 12.3 6.5V22.7h-8.6v-5.6h15.8v50.6h6v5.5zm-13.3-16.8V52c-.1-3-1.2-5.5-3.2-7.3s-4.4-2.8-7.2-2.8c-3.6 0-6.3 1.3-8.2 3.9-1.9 2.6-2.8 5.8-2.8 9.6 0 4.1 1 7.3 3 9.5s4.5 3.3 7.4 3.3c3.2 0 5.8-1.3 7.8-3.8 2.1-2.6 3.1-5.3 3.2-8zm61.5 16.8H269v-5.5h6V51.9c0-3.7-.7-6.3-2.2-7.9-1.4-1.6-3.4-2.3-5.7-2.3-3.1 0-5.6 1-7.4 3s-2.8 4.4-2.9 7v15.9h6v5.5h-19.3v-5.5h6V42.4h-6.2v-5.6h13.6V43c2.6-4.6 6.8-6.9 12.7-6.9 3.6 0 6.7 1.1 9.2 3.3s3.7 5.6 3.7 10.2v18.2h6v5.4h-.2z" class="logo-text"></path></svg></a><button title="Open main menu" type="button" class="button action has-icon main-menu-toggle" aria-haspopup="menu" aria-label="Open main menu" aria-expanded="false"><span class="button-wrap"><span class="icon icon-menu "></span><span class="visually-hidden">Open main menu</span></span></button></div><div class="top-navigation-main"><nav class="main-nav" aria-label="Main menu"><ul class="main-menu nojs"><li class="top-level-entry-container "><button type="button" id="references-button" class="top-level-entry menu-toggle" aria-controls="references-menu" aria-expanded="false">References</button><a href="/en-US/docs/Web" class="top-level-entry">References</a><ul id="references-menu" class="submenu references hidden inline-submenu-lg" aria-labelledby="references-button"><li class="apis-link-container mobile-only "><a href="/en-US/docs/Web" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Overview / Web Technology</div><p class="submenu-item-description">Web technology reference for developers</p></div></a></li><li class="html-link-container "><a href="/en-US/docs/Web/HTML" class="submenu-item "><div class="submenu-icon html"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTML</div><p class="submenu-item-description">Structure of content on the web</p></div></a></li><li class="css-link-container "><a href="/en-US/docs/Web/CSS" class="submenu-item "><div class="submenu-icon css"></div><div class="submenu-content-container"><div class="submenu-item-heading">CSS</div><p class="submenu-item-description">Code used to describe document style</p></div></a></li><li class="javascript-link-container "><a href="/en-US/docs/Web/JavaScript" class="submenu-item "><div class="submenu-icon javascript"></div><div class="submenu-content-container"><div class="submenu-item-heading">JavaScript</div><p class="submenu-item-description">General-purpose scripting language</p></div></a></li><li class="http-link-container "><a href="/en-US/docs/Web/HTTP" class="submenu-item "><div class="submenu-icon http"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTTP</div><p class="submenu-item-description">Protocol for transmitting web resources</p></div></a></li><li class="apis-link-container "><a href="/en-US/docs/Web/API" class="submenu-item "><div class="submenu-icon apis"></div><div class="submenu-content-container"><div class="submenu-item-heading">Web APIs</div><p class="submenu-item-description">Interfaces for building web applications</p></div></a></li><li class="apis-link-container "><a href="/en-US/docs/Mozilla/Add-ons/WebExtensions" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Web Extensions</div><p class="submenu-item-description">Developing extensions for web browsers</p></div></a></li><li class="apis-link-container desktop-only "><a href="/en-US/docs/Web" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Web Technology</div><p class="submenu-item-description">Web technology reference for developers</p></div></a></li></ul></li><li class="top-level-entry-container active"><button type="button" id="guides-button" class="top-level-entry menu-toggle" aria-controls="guides-menu" aria-expanded="false">Guides</button><a href="/en-US/docs/Learn" class="top-level-entry">Guides</a><ul id="guides-menu" class="submenu guides hidden inline-submenu-lg" aria-labelledby="guides-button"><li class="apis-link-container mobile-only "><a href="/en-US/docs/Learn" class="submenu-item "><div class="submenu-icon learn"></div><div class="submenu-content-container"><div class="submenu-item-heading">Overview / MDN Learning Area</div><p class="submenu-item-description">Learn web development</p></div></a></li><li class="apis-link-container desktop-only "><a href="/en-US/docs/Learn" class="submenu-item "><div class="submenu-icon learn"></div><div class="submenu-content-container"><div class="submenu-item-heading">MDN Learning Area</div><p class="submenu-item-description">Learn web development</p></div></a></li><li class="html-link-container "><a href="/en-US/docs/Learn/HTML" class="submenu-item "><div class="submenu-icon html"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTML</div><p class="submenu-item-description">Learn to structure web content with HTML</p></div></a></li><li class="css-link-container "><a href="/en-US/docs/Learn/CSS" class="submenu-item "><div class="submenu-icon css"></div><div class="submenu-content-container"><div class="submenu-item-heading">CSS</div><p class="submenu-item-description">Learn to style content using CSS</p></div></a></li><li class="javascript-link-container "><a href="/en-US/docs/Learn/JavaScript" class="submenu-item "><div class="submenu-icon javascript"></div><div class="submenu-content-container"><div class="submenu-item-heading">JavaScript</div><p class="submenu-item-description">Learn to run scripts in the browser</p></div></a></li><li class=" "><a href="/en-US/docs/Web/Accessibility" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Accessibility</div><p class="submenu-item-description">Learn to make the web accessible to all</p></div></a></li></ul></li><li class="top-level-entry-container "><button type="button" id="mdn-plus-button" class="top-level-entry menu-toggle" aria-controls="mdn-plus-menu" aria-expanded="false">Plus</button><a href="/en-US/plus" class="top-level-entry">Plus</a><ul id="mdn-plus-menu" class="submenu mdn-plus hidden inline-submenu-lg" aria-labelledby="mdn-plus-button"><li class=" "><a href="/en-US/plus" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Overview</div><p class="submenu-item-description">A customized MDN experience</p></div></a></li><li class=" "><a href="/en-US/plus/ai-help" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">AI Help</div><p class="submenu-item-description">Get real-time assistance and support</p></div></a></li><li class=" "><a href="/en-US/plus/updates" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Updates</div><p class="submenu-item-description">All browser compatibility updates at a glance</p></div></a></li><li class=" "><a href="/en-US/plus/docs/features/overview" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Documentation</div><p class="submenu-item-description">Learn how to use MDN Plus</p></div></a></li><li class=" "><a href="/en-US/plus/docs/faq" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">FAQ</div><p class="submenu-item-description">Frequently asked questions about MDN Plus</p></div></a></li></ul></li><li class="top-level-entry-container "><a class="top-level-entry menu-link" href="/en-US/curriculum/">Curriculum <sup class="new">New</sup></a></li><li class="top-level-entry-container "><a class="top-level-entry menu-link" href="/en-US/blog/">Blog</a></li><li class="top-level-entry-container "><button type="button" id="tools-button" class="top-level-entry menu-toggle" aria-controls="tools-menu" aria-expanded="false">Tools</button><ul id="tools-menu" class="submenu tools hidden inline-submenu-lg" aria-labelledby="tools-button"><li class=" "><a href="/en-US/play" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Playground</div><p class="submenu-item-description">Write, test and share your code</p></div></a></li><li class=" "><a href="/en-US/observatory" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTTP Observatory</div><p class="submenu-item-description">Scan a website for free</p></div></a></li><li class=" "><a href="/en-US/plus/ai-help" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">AI Help</div><p class="submenu-item-description">Get real-time assistance and support</p></div></a></li></ul></li></ul></nav><div class="header-search"><form action="/en-US/search" class="search-form search-widget" id="top-nav-search-form" role="search"><label id="top-nav-search-label" for="top-nav-search-input" class="visually-hidden">Search MDN</label><input aria-activedescendant="" aria-autocomplete="list" aria-controls="top-nav-search-menu" aria-expanded="false" aria-labelledby="top-nav-search-label" autoComplete="off" id="top-nav-search-input" role="combobox" type="search" class="search-input-field" name="q" placeholder=" " required="" value=""/><button type="button" class="button action has-icon clear-search-button"><span class="button-wrap"><span class="icon icon-cancel "></span><span class="visually-hidden">Clear search input</span></span></button><button type="submit" class="button action has-icon search-button"><span class="button-wrap"><span class="icon icon-search "></span><span class="visually-hidden">Search</span></span></button><div id="top-nav-search-menu" role="listbox" aria-labelledby="top-nav-search-label"></div></form></div><div class="theme-switcher-menu"><button type="button" class="button action has-icon theme-switcher-menu small" aria-haspopup="menu"><span class="button-wrap"><span class="icon icon-theme-os-default "></span>Theme</span></button></div><ul class="auth-container"><li><a href="/users/fxa/login/authenticate/?next=%2Fen-US%2Fdocs%2FLearn%2FCSS%2FBuilding_blocks%2FOrganizing" class="login-link" rel="nofollow">Log in</a></li><li><a href="/users/fxa/login/authenticate/?next=%2Fen-US%2Fdocs%2FLearn%2FCSS%2FBuilding_blocks%2FOrganizing" target="_self" rel="nofollow" class="button primary mdn-plus-subscribe-link"><span class="button-wrap">Sign up for free</span></a></li></ul></div></div></header><div class="article-actions-container"><div class="container"><button type="button" class="button action has-icon sidebar-button" aria-label="Expand sidebar" aria-expanded="false" aria-controls="sidebar-quicklinks"><span class="button-wrap"><span class="icon icon-sidebar "></span></span></button><nav class="breadcrumbs-container" aria-label="Breadcrumb"><ol typeof="BreadcrumbList" vocab="https://schema.org/" aria-label="breadcrumbs"><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn" class="breadcrumb" property="item" typeof="WebPage"><span property="name">Guides</span></a><meta property="position" content="1"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn/CSS" class="breadcrumb" property="item" typeof="WebPage"><span property="name">CSS</span></a><meta property="position" content="2"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn/CSS/Building_blocks" class="breadcrumb" property="item" typeof="WebPage"><span property="name">CSS building blocks</span></a><meta property="position" content="3"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn/CSS/Building_blocks/Organizing" class="breadcrumb-current-page" property="item" typeof="WebPage"><span property="name">Organizing your CSS</span></a><meta property="position" content="4"/></li></ol></nav><div class="article-actions"><button type="button" class="button action has-icon article-actions-toggle" aria-label="Article actions"><span class="button-wrap"><span class="icon icon-ellipses "></span><span class="article-actions-dialog-heading">Article Actions</span></span></button><ul class="article-actions-entries"><li class="article-actions-entry"><div class="languages-switcher-menu open-on-focus-within"><button id="languages-switcher-button" type="button" class="button action small has-icon languages-switcher-menu" aria-haspopup="menu"><span class="button-wrap"><span class="icon icon-language "></span>English (US)</span></button><div class="hidden"><ul class="submenu language-menu " aria-labelledby="language-menu-button"><li class=" "><form class="submenu-item locale-redirect-setting"><div class="group"><label class="switch"><input type="checkbox" name="locale-redirect"/><span class="slider"></span><span class="label">Remember language</span></label><a href="https://github.com/orgs/mdn/discussions/739" rel="external noopener noreferrer" target="_blank" title="Enable this setting to automatically switch to this language when it's available. (Click to learn more.)"><span class="icon icon-question-mark "></span></a></div></form></li><li class=" "><a data-locale="de" href="/de/docs/Learn/CSS/Building_blocks/Organizing" class="button submenu-item"><span>Deutsch</span><span title="Diese Übersetzung ist Teil eines Experiments."><span class="icon icon-experimental "></span></span></a></li><li class=" "><a data-locale="ja" href="/ja/docs/Learn/CSS/Building_blocks/Organizing" class="button submenu-item"><span>日本語</span></a></li><li class=" "><a data-locale="ko" href="/ko/docs/Learn/CSS/Building_blocks/Organizing" class="button submenu-item"><span>한국어</span></a></li><li class=" "><a data-locale="zh-CN" href="/zh-CN/docs/Learn/CSS/Building_blocks/Organizing" class="button submenu-item"><span>中文 (简体)</span></a></li></ul></div></div></li></ul></div></div></div></div><div class="main-wrapper"><div class="sidebar-container"><aside id="sidebar-quicklinks" class="sidebar" data-macro="LearnSidebar"><button type="button" class="button action backdrop" aria-label="Collapse sidebar"><span class="button-wrap"></span></button><nav aria-label="Related Topics" class="sidebar-inner"><header class="sidebar-actions"><section class="sidebar-filter-container"><div class="sidebar-filter "><label id="sidebar-filter-label" class="sidebar-filter-label" for="sidebar-filter-input"><span class="icon icon-filter"></span><span class="visually-hidden">Filter sidebar</span></label><input id="sidebar-filter-input" autoComplete="off" class="sidebar-filter-input-field false" type="text" placeholder="Filter" value=""/><button type="button" class="button action has-icon clear-sidebar-filter-button"><span class="button-wrap"><span class="icon icon-cancel "></span><span class="visually-hidden">Clear filter input</span></span></button></div></section></header><div class="sidebar-inner-nav"><div class="in-nav-toc"><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">In this article</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#tips_to_keep_your_css_tidy">Tips to keep your CSS tidy</a></li><li class="document-toc-item "><a class="document-toc-link" href="#other_tools_that_can_help">Other tools that can help</a></li><li class="document-toc-item "><a class="document-toc-link" href="#summary">Summary</a></li></ul></section></div></div><div class="sidebar-body"><ol><li class="section"><a href="/en-US/docs/Learn/Getting_started_with_the_web">Complete beginners start here!</a></li><li><details><summary>Getting started with the web</summary><ol><li><a href="/en-US/docs/Learn/Getting_started_with_the_web">Getting started with the web</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/Installing_basic_software">Installing basic software</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/What_will_your_website_look_like">What will your website look like?</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/Dealing_with_files">Dealing with files</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/HTML_basics">HTML basics</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/CSS_basics">CSS basics</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/JavaScript_basics">JavaScript basics</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/Publishing_your_website">Publishing your website</a></li><li><a href="/en-US/docs/Learn/Getting_started_with_the_web/How_the_Web_works">How the web works</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/HTML">HTML — Structuring the web</a></li><li><details><summary>Introduction to HTML</summary><ol><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML">Introduction to HTML</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Getting_started">Getting started with HTML</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML">What's in the head? Metadata in HTML</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/HTML_text_fundamentals">HTML text fundamentals</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Creating_hyperlinks">Creating hyperlinks</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Advanced_text_formatting">Advanced text formatting</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Document_and_website_structure">Document and website structure</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Debugging_HTML">Debugging HTML</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter">Marking up a letter</a></li><li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Structuring_a_page_of_content">Structuring a page of content</a></li></ol></details></li><li><details><summary>Multimedia and embedding</summary><ol><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding">Multimedia and embedding</a></li><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Images_in_HTML">Images in HTML</a></li><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content">Video and audio content</a></li><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Other_embedding_technologies">From object to iframe — other embedding technologies</a></li><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Adding_vector_graphics_to_the_Web">Adding vector graphics to the web</a></li><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images">Responsive images</a></li><li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Mozilla_splash_page">Mozilla splash page</a></li></ol></details></li><li><details><summary>HTML tables</summary><ol><li><a href="/en-US/docs/Learn/HTML/Tables">HTML tables</a></li><li><a href="/en-US/docs/Learn/HTML/Tables/Basics">HTML table basics</a></li><li><a href="/en-US/docs/Learn/HTML/Tables/Advanced">HTML table advanced features and accessibility</a></li><li><a href="/en-US/docs/Learn/HTML/Tables/Structuring_planet_data">Structuring planet data</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/CSS">CSS — Styling the web</a></li><li><details><summary>CSS first steps</summary><ol><li><a href="/en-US/docs/Learn/CSS/First_steps">CSS first steps</a></li><li><a href="/en-US/docs/Learn/CSS/First_steps/What_is_CSS">What is CSS?</a></li><li><a href="/en-US/docs/Learn/CSS/First_steps/Getting_started">Getting started with CSS</a></li><li><a href="/en-US/docs/Learn/CSS/First_steps/How_CSS_is_structured">How CSS is structured</a></li><li><a href="/en-US/docs/Learn/CSS/First_steps/How_CSS_works">How CSS works</a></li><li><a href="/en-US/docs/Learn/CSS/First_steps/Styling_a_biography_page">Styling a biography page</a></li></ol></details></li><li><details open=""><summary>CSS building blocks</summary><ol><li><a href="/en-US/docs/Learn/CSS/Building_blocks">CSS building blocks</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Selectors">CSS selectors</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors">Type, class, and ID selectors</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Selectors/Attribute_selectors">Attribute selectors</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements">Pseudo-classes and pseudo-elements</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Selectors/Combinators">Combinators</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Cascade_and_inheritance">Cascade, specificity, and inheritance</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Cascade_layers">Cascade layers</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/The_box_model">The box model</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Backgrounds_and_borders">Backgrounds and borders</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Handling_different_text_directions">Handling different text directions</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Overflowing_content">Overflowing content</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Values_and_units">CSS values and units</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS">Sizing items in CSS</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Images_media_form_elements">Images, media, and form elements</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Styling_tables">Styling tables</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Advanced_styling_effects">Advanced styling effects</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Debugging_CSS">Debugging CSS</a></li><li><em><a href="/en-US/docs/Learn/CSS/Building_blocks/Organizing" aria-current="page">Organizing your CSS</a></em></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension">Fundamental CSS comprehension</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/Creating_fancy_letterheaded_paper">Creating fancy letterheaded paper</a></li><li><a href="/en-US/docs/Learn/CSS/Building_blocks/A_cool_looking_box">A cool-looking box</a></li></ol></details></li><li><details><summary>Styling text</summary><ol><li><a href="/en-US/docs/Learn/CSS/Styling_text">CSS styling text</a></li><li><a href="/en-US/docs/Learn/CSS/Styling_text/Fundamentals">Fundamental text and font styling</a></li><li><a href="/en-US/docs/Learn/CSS/Styling_text/Styling_lists">Styling lists</a></li><li><a href="/en-US/docs/Learn/CSS/Styling_text/Styling_links">Styling links</a></li><li><a href="/en-US/docs/Learn/CSS/Styling_text/Web_fonts">Web fonts</a></li><li><a href="/en-US/docs/Learn/CSS/Styling_text/Typesetting_a_homepage">Typesetting a community school homepage</a></li></ol></details></li><li><details><summary>CSS layout</summary><ol><li><a href="/en-US/docs/Learn/CSS/CSS_layout">CSS layout</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Introduction">Introduction to CSS layout</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Normal_Flow">Normal Flow</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Flexbox">Flexbox</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Grids">Grids</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Floats">Floats</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Positioning">Positioning</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Multiple-column_Layout">Multiple-column layout</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Responsive_Design">Responsive design</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Media_queries">Beginner's guide to media queries</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Legacy_Layout_Methods">Legacy layout methods</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Supporting_Older_Browsers">Supporting older browsers</a></li><li><a href="/en-US/docs/Learn/CSS/CSS_layout/Fundamental_Layout_Comprehension">Fundamental layout comprehension</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/JavaScript">JavaScript — Dynamic client-side scripting</a></li><li><details><summary>JavaScript first steps</summary><ol><li><a href="/en-US/docs/Learn/JavaScript/First_steps">JavaScript first steps</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/What_is_JavaScript">What is JavaScript?</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/A_first_splash">A first splash into JavaScript</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/What_went_wrong">What went wrong? Troubleshooting JavaScript</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/Variables">Storing the information you need — Variables</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/Math">Basic math in JavaScript — numbers and operators</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/Strings">Handling text — strings in JavaScript</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/Useful_string_methods">Useful string methods</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/Arrays">Arrays</a></li><li><a href="/en-US/docs/Learn/JavaScript/First_steps/Silly_story_generator">Silly story generator</a></li></ol></details></li><li><details><summary>JavaScript building blocks</summary><ol><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks">JavaScript building blocks</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/conditionals">Making decisions in your code — conditionals</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Looping_code">Looping code</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Functions">Functions — reusable blocks of code</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Build_your_own_function">Build your own function</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Return_values">Function return values</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Events">Introduction to events</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Event_bubbling">Event bubbling</a></li><li><a href="/en-US/docs/Learn/JavaScript/Building_blocks/Image_gallery">Image gallery</a></li></ol></details></li><li><details><summary>Introducing JavaScript objects</summary><ol><li><a href="/en-US/docs/Learn/JavaScript/Objects">Introducing JavaScript objects</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/Basics">JavaScript object basics</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/Object_prototypes">Object prototypes</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/Object-oriented_programming">Object-oriented programming</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/Classes_in_JavaScript">Classes in JavaScript</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/JSON">Working with JSON</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/Object_building_practice">Object building practice</a></li><li><a href="/en-US/docs/Learn/JavaScript/Objects/Adding_bouncing_balls_features">Adding features to our bouncing balls demo</a></li></ol></details></li><li><details><summary>Asynchronous JavaScript</summary><ol><li><a href="/en-US/docs/Learn/JavaScript/Asynchronous">Asynchronous JavaScript</a></li><li><a href="/en-US/docs/Learn/JavaScript/Asynchronous/Introducing">Introducing asynchronous JavaScript</a></li><li><a href="/en-US/docs/Learn/JavaScript/Asynchronous/Promises">How to use promises</a></li><li><a href="/en-US/docs/Learn/JavaScript/Asynchronous/Implementing_a_promise-based_API">How to implement a promise-based API</a></li><li><a href="/en-US/docs/Learn/JavaScript/Asynchronous/Introducing_workers">Introducing workers</a></li><li><a href="/en-US/docs/Learn/JavaScript/Asynchronous/Sequencing_animations">Sequencing animations</a></li></ol></details></li><li><details><summary>Client-side web APIs</summary><ol><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs">Client-side web APIs</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Introduction">Introduction to web APIs</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents">Manipulating documents</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Fetching_data">Fetching data from the server</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Third_party_APIs">Third-party APIs</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Drawing_graphics">Drawing graphics</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Video_and_audio_APIs">Video and Audio APIs</a></li><li><a href="/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Client-side_storage">Client-side storage</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/Forms">Web forms — Working with user data</a></li><li><details><summary>Web form building blocks</summary><ol><li><a href="/en-US/docs/Learn/Forms">Web form building blocks</a></li><li><a href="/en-US/docs/Learn/Forms/Your_first_form">Your first form</a></li><li><a href="/en-US/docs/Learn/Forms/How_to_structure_a_web_form">How to structure a web form</a></li><li><a href="/en-US/docs/Learn/Forms/Basic_native_form_controls">Basic native form controls</a></li><li><a href="/en-US/docs/Learn/Forms/HTML5_input_types">The HTML5 input types</a></li><li><a href="/en-US/docs/Learn/Forms/Other_form_controls">Other form controls</a></li><li><a href="/en-US/docs/Learn/Forms/Styling_web_forms">Styling web forms</a></li><li><a href="/en-US/docs/Learn/Forms/Advanced_form_styling">Advanced form styling</a></li><li><a href="/en-US/docs/Learn/Forms/UI_pseudo-classes">UI pseudo-classes</a></li><li><a href="/en-US/docs/Learn/Forms/Form_validation">Client-side form validation</a></li><li><a href="/en-US/docs/Learn/Forms/Sending_and_retrieving_form_data">Sending form data</a></li></ol></details></li><li><details><summary>Advanced web form techniques</summary><ol><li><a href="/en-US/docs/Learn/Forms/How_to_build_custom_form_controls">How to build custom form controls</a></li><li><a href="/en-US/docs/Learn/Forms/Sending_forms_through_JavaScript">Sending forms through JavaScript</a></li><li><a href="/en-US/docs/Learn/Forms/Property_compatibility_table_for_form_controls">CSS property compatibility table for form controls</a></li><li><a href="/en-US/docs/Learn/Forms/HTML_forms_in_legacy_browsers">HTML forms in legacy browsers</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/Accessibility">Accessibility — Make the web usable by everyone</a></li><li><details><summary>Accessibility guides</summary><ol><li><a href="/en-US/docs/Learn/Accessibility">Accessibility</a></li><li><a href="/en-US/docs/Learn/Accessibility/What_is_accessibility">What is accessibility?</a></li><li><a href="/en-US/docs/Learn/Accessibility/HTML">HTML: A good basis for accessibility</a></li><li><a href="/en-US/docs/Learn/Accessibility/CSS_and_JavaScript">CSS and JavaScript accessibility best practices</a></li><li><a href="/en-US/docs/Learn/Accessibility/WAI-ARIA_basics">WAI-ARIA basics</a></li><li><a href="/en-US/docs/Learn/Accessibility/Multimedia">Accessible multimedia</a></li><li><a href="/en-US/docs/Learn/Accessibility/Mobile">Mobile accessibility</a></li><li><a href="/en-US/docs/Learn/Accessibility/Accessibility_troubleshooting">Assessment: Accessibility troubleshooting</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/Performance">Performance — Making websites fast and responsive</a></li><li><details><summary>Performance guides</summary><ol><li><a href="/en-US/docs/Learn/Performance">Web performance</a></li><li><a href="/en-US/docs/Learn/Performance/why_web_performance">The "why" of web performance</a></li><li><a href="/en-US/docs/Learn/Performance/What_is_web_performance">What is web performance?</a></li><li><a href="/en-US/docs/Learn/Performance/Perceived_performance">Perceived performance</a></li><li><a href="/en-US/docs/Learn/Performance/Measuring_performance">Measuring performance</a></li><li><a href="/en-US/docs/Learn/Performance/Multimedia">Multimedia: Images</a></li><li><a href="/en-US/docs/Learn/Performance/video">Multimedia: video</a></li><li><a href="/en-US/docs/Learn/Performance/JavaScript">JavaScript performance optimization</a></li><li><a href="/en-US/docs/Learn/Performance/HTML">HTML performance optimization</a></li><li><a href="/en-US/docs/Learn/Performance/CSS">CSS performance optimization</a></li><li><a href="/en-US/docs/Learn/Performance/business_case_for_performance">The business case for web performance</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/MathML">MathML — Writing mathematics with MathML</a></li><li><details><summary>MathML first steps</summary><ol><li><a href="/en-US/docs/Learn/MathML/First_steps">MathML first steps</a></li><li><a href="/en-US/docs/Learn/MathML/First_steps/Getting_started">Getting started with MathML</a></li><li><a href="/en-US/docs/Learn/MathML/First_steps/Text_containers">MathML Text Containers</a></li><li><a href="/en-US/docs/Learn/MathML/First_steps/Fractions_and_roots">MathML fractions and roots</a></li><li><a href="/en-US/docs/Learn/MathML/First_steps/Scripts">MathML scripted elements</a></li><li><a href="/en-US/docs/Learn/MathML/First_steps/Tables">MathML tables</a></li><li><a href="/en-US/docs/Learn/MathML/First_steps/Three_famous_mathematical_formulas">Three famous mathematical formulas</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/../Games">Games — Developing games for the web</a></li><li><details><summary>Guides and tutorials</summary><ol><li><a href="/en-US/docs/Games/Introduction">Introduction to game development for the Web</a></li><li><a href="/en-US/docs/Games/Techniques">Techniques for game development</a></li><li><a href="/en-US/docs/Games/Tutorials">Tutorials</a></li><li><a href="/en-US/docs/Games/Publishing_games">Publishing games</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/Tools_and_testing">Tools and testing</a></li><li><details><summary>Client-side web development tools</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools">Understanding client-side web development tools</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Overview">Client-side tooling overview</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Command_line">Command line crash course</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Package_management">Package management basics</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Introducing_complete_toolchain">Introducing a complete toolchain</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Deployment">Deploying our app</a></li></ol></details></li><li><details><summary>Introduction to client-side frameworks</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Introduction">Introduction to client-side frameworks</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Main_features">Framework main features</a></li></ol></details></li><li><details><summary>React</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_getting_started">Getting started with React</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_todo_list_beginning">Beginning our React todo list</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_components">Componentizing our React app</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_events_state">React interactivity: Events and state</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_filtering_conditional_rendering">React interactivity: Editing, filtering, conditional rendering</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_accessibility">Accessibility in React</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_resources">React resources</a></li></ol></details></li><li><details><summary>Ember</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_getting_started">Getting started with Ember</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_structure_componentization">Ember app structure and componentization</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_interactivity_events_state">Ember interactivity: Events, classes and state</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_conditional_footer">Ember Interactivity: Footer functionality, conditional rendering</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_routing">Routing in Ember</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_resources">Ember resources and troubleshooting</a></li></ol></details></li><li><details><summary>Vue</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_getting_started">Getting started with Vue</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_first_component">Creating our first Vue component</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_rendering_lists">Rendering a list of Vue components</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_methods_events_models">Adding a new todo form: Vue events, methods, and models</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_styling">Styling Vue components with CSS</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_computed_properties">Using Vue computed properties</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_conditional_rendering">Vue conditional rendering: editing existing todos</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_refs_focus_management">Vue refs and lifecycle methods for focus management</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_resources">Vue resources</a></li></ol></details></li><li><details><summary>Svelte</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_getting_started">Getting started with Svelte</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_Todo_list_beginning">Starting our Svelte to-do list app</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_variables_props">Dynamic behavior in Svelte: working with variables and props</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_components">Componentizing our Svelte app</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_reactivity_lifecycle_accessibility">Advanced Svelte: Reactivity, lifecycle, accessibility</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_stores">Working with Svelte stores</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_TypeScript">TypeScript support in Svelte</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_deployment_next">Deployment and next steps</a></li></ol></details></li><li><details><summary>Angular</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_getting_started">Getting started with Angular</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_todo_list_beginning">Beginning our Angular todo list app</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_styling">Styling our Angular app</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_item_component">Creating an item component</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_filtering">Filtering our to-do items</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_building">Building Angular applications and further resources</a></li></ol></details></li><li><details><summary>Git and GitHub</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/GitHub">Git and GitHub</a></li></ol></details></li><li><details><summary>Cross browser testing</summary><ol><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing">Cross browser testing</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Introduction">Introduction to cross-browser testing</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Testing_strategies">Strategies for carrying out testing</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/HTML_and_CSS">Handling common HTML and CSS problems</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/JavaScript">Handling common JavaScript problems</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Accessibility">Handling common accessibility problems</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Feature_detection">Implementing feature detection</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Automated_testing">Introduction to automated testing</a></li><li><a href="/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Your_own_automation_environment">Setting up your own test automation environment</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/Server-side">Server-side website programming</a></li><li><details><summary>First steps</summary><ol><li><a href="/en-US/docs/Learn/Server-side/First_steps">Server-side website programming first steps</a></li><li><a href="/en-US/docs/Learn/Server-side/First_steps/Introduction">Introduction to the server side</a></li><li><a href="/en-US/docs/Learn/Server-side/First_steps/Client-Server_overview">Client-Server Overview</a></li><li><a href="/en-US/docs/Learn/Server-side/First_steps/Web_frameworks">Server-side web frameworks</a></li><li><a href="/en-US/docs/Learn/Server-side/First_steps/Website_security">Website security</a></li></ol></details></li><li><details><summary>Django web framework (Python)</summary><ol><li><a href="/en-US/docs/Learn/Server-side/Django">Django Web Framework (Python)</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Introduction">Django introduction</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/development_environment">Setting up a Django development environment</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Tutorial_local_library_website">Django Tutorial: The Local Library website</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/skeleton_website">Django Tutorial Part 2: Creating a skeleton website</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Models">Django Tutorial Part 3: Using models</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Admin_site">Django Tutorial Part 4: Django admin site</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Home_page">Django Tutorial Part 5: Creating our home page</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Generic_views">Django Tutorial Part 6: Generic list and detail views</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Sessions">Django Tutorial Part 7: Sessions framework</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Authentication">Django Tutorial Part 8: User authentication and permissions</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Forms">Django Tutorial Part 9: Working with forms</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Testing">Django Tutorial Part 10: Testing a Django web application</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/Deployment">Django Tutorial Part 11: Deploying Django to production</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/web_application_security">Django web application security</a></li><li><a href="/en-US/docs/Learn/Server-side/Django/django_assessment_blog">Assessment: DIY Django mini blog</a></li></ol></details></li><li><details><summary>Express Web Framework (Node.js/JavaScript)</summary><ol><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs">Express web framework (Node.js/JavaScript)</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/Introduction">Express/Node introduction</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/development_environment">Setting up a Node development environment</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/Tutorial_local_library_website">Express Tutorial: The Local Library website</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/skeleton_website">Express Tutorial Part 2: Creating a skeleton website</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/mongoose">Express Tutorial Part 3: Using a Database (with Mongoose)</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/routes">Express Tutorial Part 4: Routes and controllers</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/Displaying_data">Express Tutorial Part 5: Displaying library data</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/forms">Express Tutorial Part 6: Working with forms</a></li><li><a href="/en-US/docs/Learn/Server-side/Express_Nodejs/deployment">Express Tutorial Part 7: Deploying to production</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn/Common_questions">Further resources</a></li><li><details><summary>Common questions</summary><ol><li><a href="/en-US/docs/Learn/Common_questions">Common questions</a></li><li><a href="/en-US/docs/Learn/HTML/Howto">Use HTML to solve common problems</a></li><li><a href="/en-US/docs/Learn/CSS/Howto">Use CSS to solve common problems</a></li><li><a href="/en-US/docs/Learn/JavaScript/Howto">Solve common problems in your JavaScript code</a></li><li><a href="/en-US/docs/Learn/Common_questions/Web_mechanics">Web mechanics</a></li><li><a href="/en-US/docs/Learn/Common_questions/Tools_and_setup">Tools and setup</a></li><li><a href="/en-US/docs/Learn/Common_questions/Design_and_accessibility">Design and accessibility</a></li></ol></details></li></ol></div></div><section class="place side"></section></nav></aside><div class="toc-container"><aside class="toc"><nav><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">In this article</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#tips_to_keep_your_css_tidy">Tips to keep your CSS tidy</a></li><li class="document-toc-item "><a class="document-toc-link" href="#other_tools_that_can_help">Other tools that can help</a></li><li class="document-toc-item "><a class="document-toc-link" href="#summary">Summary</a></li></ul></section></div></nav></aside><section class="place side"></section></div></div><main id="content" class="main-content "><article class="main-page-content" lang="en-US"><header><h1>Organizing your CSS</h1></header><div class="section-content"><ul class="prev-next"> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks/Debugging_CSS"><span class="button-wrap"> Previous </span></a></li> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks"><span class="button-wrap"> Overview: CSS building blocks</span></a></li> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension"><span class="button-wrap"> Next </span></a></li> </ul> <p>As you start to work on larger stylesheets and big projects you will discover that maintaining a huge CSS file can be challenging. In this article we will take a brief look at some best practices for writing your CSS to make it easily maintainable, and some of the solutions you will find in use by others to help improve maintainability.</p> <figure class="table-container"><table> <tbody> <tr> <th scope="row">Prerequisites:</th> <td> <a href="/en-US/docs/Learn/Getting_started_with_the_web/Installing_basic_software">Basic software installed</a>, basic knowledge of <a href="/en-US/docs/Learn/Getting_started_with_the_web/Dealing_with_files">working with files</a>, HTML basics (study <a href="/en-US/docs/Learn/HTML/Introduction_to_HTML">Introduction to HTML</a>), and an idea of how CSS works (study <a href="/en-US/docs/Learn/CSS/First_steps">CSS first steps</a>.) </td> </tr> <tr> <th scope="row">Objective:</th> <td> To learn some tips and best practices for organizing stylesheets, and find out about some of the naming conventions and tools in common usage to help with CSS organization and team working. </td> </tr> </tbody> </table></figure></div><section aria-labelledby="tips_to_keep_your_css_tidy"><h2 id="tips_to_keep_your_css_tidy"><a href="#tips_to_keep_your_css_tidy">Tips to keep your CSS tidy</a></h2><div class="section-content"><p>Here are some general suggestions for ways to keep your stylesheets organized and tidy.</p></div></section><section aria-labelledby="does_your_project_have_a_coding_style_guide"><h3 id="does_your_project_have_a_coding_style_guide"><a href="#does_your_project_have_a_coding_style_guide">Does your project have a coding style guide?</a></h3><div class="section-content"><p>If you are working with a team on an existing project, the first thing to check is whether the project has an existing style guide for CSS. The team style guide should always win over your own personal preferences. There often isn't a right or wrong way to do things, but consistency is important.</p> <p>For example, have a look at the <a href="/en-US/docs/MDN/Writing_guidelines/Writing_style_guide/Code_style_guide/CSS">CSS guidelines for MDN code examples</a>.</p></div></section><section aria-labelledby="keep_it_consistent"><h3 id="keep_it_consistent"><a href="#keep_it_consistent">Keep it consistent</a></h3><div class="section-content"><p>If you get to set the rules for the project or are working alone, then the most important thing to do is to keep things consistent. Consistency can be applied in all sorts of ways, such as using the same naming conventions for classes, choosing one method of describing color, or maintaining consistent formatting. (For example, will you use tabs or spaces to indent your code? If spaces, how many spaces?)</p> <p>Having a set of rules you always follow reduces the amount of mental overhead needed when writing CSS, as some of the decisions are already made.</p></div></section><section aria-labelledby="formatting_readable_css"><h3 id="formatting_readable_css"><a href="#formatting_readable_css">Formatting readable CSS</a></h3><div class="section-content"><p>There are a couple of ways you will see CSS formatted. Some developers put all of the rules onto a single line, like so:</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.box {background-color: #567895; } h2 {background-color: black; color: white; } </code></pre></div> <p>Other developers prefer to break everything onto a new line:</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.box { background-color: #567895; } h2 { background-color: black; color: white; } </code></pre></div> <p>CSS doesn't mind which one you use. We personally find it is more readable to have each property and value pair on a new line.</p></div></section><section aria-labelledby="comment_your_css"><h3 id="comment_your_css"><a href="#comment_your_css">Comment your CSS</a></h3><div class="section-content"><p>Adding comments to your CSS will help any future developer work with your CSS file, but will also help you when you come back to the project after a break.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>/* This is a CSS comment It can be broken onto multiple lines. */ </code></pre></div> <p>A good tip is to add a block of comments between logical sections in your stylesheet too, to help locate different sections quickly when scanning it, or even to give you something to search for to jump right into that part of the CSS. If you use a string that won't appear in the code, you can jump from section to section by searching for it — below we have used <code>||</code>.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>/* || General styles */ /* … */ /* || Typography */ /* … */ /* || Header and Main Navigation */ /* … */ </code></pre></div> <p>You don't need to comment every single thing in your CSS, as much of it will be self-explanatory. What you should comment are the things where you made a particular decision for a reason.</p> <p>You may have used a CSS property in a specific way to get around older browser incompatibilities, for example:</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.box { background-color: red; /* fallback for older browsers that don't support gradients */ background-image: linear-gradient(to right, #ff0000, #aa0000); } </code></pre></div> <p>Perhaps you followed a tutorial to achieve something, and the CSS isn't very self-explanatory or recognizable. In that case, you could add the URL of the tutorial to the comments. You will thank yourself when you come back to this project in a year or so and can vaguely remember that there was a great tutorial about that thing, but can't recall where it's from.</p></div></section><section aria-labelledby="create_logical_sections_in_your_stylesheet"><h3 id="create_logical_sections_in_your_stylesheet"><a href="#create_logical_sections_in_your_stylesheet">Create logical sections in your stylesheet</a></h3><div class="section-content"><p>It is a good idea to have all of the common styling first in the stylesheet. This means all of the styles which will generally apply unless you do something special with that element. You will typically have rules set up for:</p> <ul> <li><code>body</code></li> <li><code>p</code></li> <li><code>h1</code>, <code>h2</code>, <code>h3</code>, <code>h4</code>, <code>h5</code></li> <li><code>ul</code> and <code>ol</code></li> <li>The <code>table</code> properties</li> <li>Links</li> </ul> <p>In this section of the stylesheet we are providing default styling for the type on the site, setting up a default style for data tables and lists and so on.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>/* || GENERAL STYLES */ body { /* … */ } h1, h2, h3, h4 { /* … */ } ul { /* … */ } blockquote { /* … */ } </code></pre></div> <p>After this section, we could define a few utility classes, for example, a class that removes the default list style for lists we're going to display as flex items or in some other way. If you have a few styling choices you know you will want to apply to lots of different elements, they can be put in this section.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>/* || UTILITIES */ .no-bullets { list-style: none; margin: 0; padding: 0; } /* … */ </code></pre></div> <p>Then we can add everything that is used sitewide. That might be things like the basic page layout, the header, navigation styling, and so on.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>/* SITEWIDE */ .main-nav { /* … */ } .logo { /* … */ } </code></pre></div> <p>Finally, we will include CSS for specific things, broken down by the context, page, or even component in which they are used.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>/* || STORE PAGES */ .product-listing { /* … */ } .product-box { /* … */ } </code></pre></div> <p>By ordering things in this way, we at least have an idea in which part of the stylesheet we will be looking for something that we want to change.</p></div></section><section aria-labelledby="avoid_overly-specific_selectors"><h3 id="avoid_overly-specific_selectors"><a href="#avoid_overly-specific_selectors">Avoid overly-specific selectors</a></h3><div class="section-content"><p>If you create very specific selectors, you will often find that you need to duplicate chunks of your CSS to apply the same rules to another element. For example, you might have something like the selector below, which applies the rule to a <code><p></code> with a class of <code>box</code> inside an <code><article></code> with a class of <code>main</code>.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>article.main p.box { border: 1px solid #ccc; } </code></pre></div> <p>If you then wanted to apply the same rules to something outside of <code>main</code>, or to something other than a <code><p></code>, you would have to add another selector to these rules or create a whole new ruleset. Instead, you could use the selector <code>.box</code> to apply your rule to any element that has the class <code>box</code>:</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.box { border: 1px solid #ccc; } </code></pre></div> <p>There will be times when making something more specific makes sense; however, this will generally be an exception rather than usual practice.</p></div></section><section aria-labelledby="break_large_stylesheets_into_multiple_smaller_ones"><h3 id="break_large_stylesheets_into_multiple_smaller_ones"><a href="#break_large_stylesheets_into_multiple_smaller_ones">Break large stylesheets into multiple smaller ones</a></h3><div class="section-content"><p>In cases where you have very different styles for distinct parts of the site, you might want to have one stylesheet that includes all the global rules, as well as some smaller stylesheets that include the specific rules needed for those sections. You can link to multiple stylesheets from one page, and the normal rules of the cascade apply, with rules in stylesheets linked later coming after rules in stylesheets linked earlier.</p> <p>For example, we might have an online store as part of the site, with a lot of CSS used only for styling the product listings and forms needed for the store. It would make sense to have those things in a different stylesheet, only linked to on store pages.</p> <p>This can make it easier to keep your CSS organized, and also means that if multiple people are working on the CSS, you will have fewer situations where two people need to work on the same stylesheet at once, leading to conflicts in source control.</p></div></section><section aria-labelledby="other_tools_that_can_help"><h2 id="other_tools_that_can_help"><a href="#other_tools_that_can_help">Other tools that can help</a></h2><div class="section-content"><p>CSS itself doesn't have much in the way of in-built organization; therefore, the level of consistency in your CSS will largely depend on you. The web community has developed various tools and approaches that can help you to manage larger CSS projects. Since you are likely to come across these aids when working with other people, and since they are often of help generally, we've included a short guide to some of them.</p></div></section><section aria-labelledby="css_methodologies"><h3 id="css_methodologies"><a href="#css_methodologies">CSS methodologies</a></h3><div class="section-content"><p>Instead of needing to come up with your own rules for writing CSS, you may benefit from adopting one of the approaches already designed by the community and tested across many projects. These methodologies are essentially CSS coding guides that take a very structured approach to writing and organizing CSS. Typically they tend to render CSS more verbosely than you might have if you wrote and optimized every selector to a custom set of rules for that project.</p> <p>However, you do gain a lot of structure by adopting one. Since many of these systems are widely used, other developers are more likely to understand the approach you are using and be able to write their own CSS in the same way, rather than having to work out your own personal methodology from scratch.</p> <h4 id="oocss">OOCSS</h4> <p>Most of the approaches you will encounter owe something to the concept of Object Oriented CSS (OOCSS), an approach made popular by <a href="https://github.com/stubbornella/oocss/wiki" class="external" target="_blank">the work of Nicole Sullivan</a>. The basic idea of OOCSS is to separate your CSS into reusable objects, which can be used anywhere you need on your site. The standard example of OOCSS is the pattern described as <a href="/en-US/docs/Web/CSS/Layout_cookbook/Media_objects">The Media Object</a>. This is a pattern with a fixed size image, video or other element on one side, and flexible content on the other. It's a pattern we see all over websites for comments, listings, and so on.</p> <p>If you are not taking an OOCSS approach you might create a custom CSS for the different places this pattern is used, for example, by creating two classes, one called <code>comment</code> with a bunch of rules for the component parts, and another called <code>list-item</code> with almost the same rules as the <code>comment</code> class except for some tiny differences. The differences between these two components are the list-item has a bottom border, and images in comments have a border whereas list-item images do not.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.comment { display: grid; grid-template-columns: 1fr 3fr; } .comment img { border: 1px solid grey; } .comment .content { font-size: 0.8rem; } .list-item { display: grid; grid-template-columns: 1fr 3fr; border-bottom: 1px solid grey; } .list-item .content { font-size: 0.8rem; } </code></pre></div> <p>In OOCSS, you would create one pattern called <code>media</code> that would have all of the common CSS for both patterns — a base class for things that are generally the shape of the media object. Then we'd add an additional class to deal with those tiny differences, thus extending that styling in specific ways.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.media { display: grid; grid-template-columns: 1fr 3fr; } .media .content { font-size: 0.8rem; } .comment img { border: 1px solid grey; } .list-item { border-bottom: 1px solid grey; } </code></pre></div> <p>In your HTML, the comment would need both the <code>media</code> and <code>comment</code> classes applied:</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html notranslate"><code><div class="media comment"> <img src="" alt="" /> <div class="content"></div> </div> </code></pre></div> <p>The list-item would have <code>media</code> and <code>list-item</code> applied:</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html notranslate"><code><ul> <li class="media list-item"> <img src="" alt="" /> <div class="content"></div> </li> </ul> </code></pre></div> <p>The work that Nicole Sullivan did in describing this approach and promoting it means that even people who are not strictly following an OOCSS approach today will generally be reusing CSS in this way — it has entered our understanding as a good way to approach things in general.</p> <h4 id="bem">BEM</h4> <p>BEM stands for Block Element Modifier. In BEM a block is a stand-alone entity such as a button, menu, or logo. An element is something like a list item or a title that is tied to the block it is in. A modifier is a flag on a block or element that changes the styling or behavior. You will be able to recognize code that uses BEM due to the extensive use of dashes and underscores in the CSS classes. For example, look at the classes applied to this HTML from the page about <a href="https://getbem.com/naming/" class="external" target="_blank">BEM Naming conventions</a>:</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html notranslate"><code><form class="form form--theme-xmas form--simple"> <label class="label form__label" for="inputId"></label> <input class="form__input" type="text" id="inputId" /> <input class="form__submit form__submit--disabled" type="submit" value="Submit" /> </form> </code></pre></div> <p>The additional classes are similar to those used in the OOCSS example; however, they use the strict naming conventions of BEM.</p> <p>BEM is widely used in larger web projects and many people write their CSS in this way. It is likely that you will come across examples, even in tutorials, that use BEM syntax, without mentioning why the CSS is structured in such a way.</p> <p>Read more about this system <a href="https://css-tricks.com/bem-101/" class="external" target="_blank">BEM 101</a> on CSS Tricks.</p> <h4 id="other_common_systems">Other common systems</h4> <p>There are a large number of these systems in use. Other popular approaches include <a href="https://smacss.com/" class="external" target="_blank">Scalable and Modular Architecture for CSS (SMACSS)</a>, created by Jonathan Snook, <a href="https://itcss.io/" class="external" target="_blank">ITCSS</a> from Harry Roberts, and <a href="https://acss-io.github.io/atomizer/" class="external" target="_blank">Atomizer CSS (ACSS)</a>, originally created by Yahoo!. If you come across a project that uses one of these approaches, then the advantage is that you will be able to search and find many articles and guides to help you understand how to code in the same style.</p> <p>The disadvantage of using such a system is that they can seem overly complex, especially for smaller projects.</p></div></section><section aria-labelledby="build_systems_for_css"><h3 id="build_systems_for_css"><a href="#build_systems_for_css">Build systems for CSS</a></h3><div class="section-content"><p>Another way to organize CSS is to take advantage of some of the tooling that is available for front-end developers, which allows you to take a slightly more programmatic approach to writing CSS. There are a number of tools, which we refer to as <em>pre-processors</em> and <em>post-processors</em>. A pre-processor runs over your raw files and turns them into a stylesheet, whereas a post-processor takes your finished stylesheet and does something to it — perhaps to optimize it in order that it will load faster.</p> <p>Using any of these tools will require that your development environment be able to run the scripts that do the pre- and post-processing. Many code editors can do this for you, or you can install command line tools to help.</p> <p>The most popular pre-processor is <a href="https://sass-lang.com/" class="external" target="_blank">Sass</a>. This is not a Sass tutorial, so I will briefly explain a couple of the things that Sass can do, which are really helpful in terms of organization even if you don't use any of the other Sass features. If you want to learn a lot more about Sass, start with the <a href="https://sass-lang.com/guide/" class="external" target="_blank">Sass basics</a> article, then move on to their other documentation.</p> <h4 id="defining_variables">Defining variables</h4> <p>CSS now has native <a href="/en-US/docs/Web/CSS/Using_CSS_custom_properties">custom properties</a>, making this feature increasingly less important. However, one of the reasons you might use Sass is to be able to define all of the colors and fonts used in a project as settings, then to use that variable around the project. This means that if you realize you have used the wrong shade of blue, you only need change it in one place.</p> <p>If we created a variable called <code>$base-color</code>, as in the first line below, we could then use it through the stylesheet anywhere that required that color.</p> <div class="code-example"><div class="example-header"><span class="language-name">scss</span></div><pre class="brush: scss notranslate"><code>$base-color: #c6538c; .alert { border: 1px solid $base-color; } </code></pre></div> <p>Once compiled to CSS, you would end up with the following CSS in the final stylesheet.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>.alert { border: 1px solid #c6538c; } </code></pre></div> <h4 id="compiling_component_stylesheets">Compiling component stylesheets</h4> <p>I mentioned above that one way to organize CSS is to break down stylesheets into smaller stylesheets. When using Sass you can take this to another level and have lots of very small stylesheets — even going as far as having a separate stylesheet for each component. By using the included functionality in Sass (partials), these can all be compiled together into one or a small number of stylesheets to actually link into your website.</p> <p>So, for example, with <a href="https://sass-lang.com/documentation/at-rules/use/#partials" class="external" target="_blank">partials</a>, you could have several style files inside a directory, say <code>foundation/_code.scss</code>, <code>foundation/_lists.scss</code>, <code>foundation/_footer.scss</code>, <code>foundation/_links.scss</code>, etc. You could then use the Sass <code>@use</code> rule to load them into other stylesheets:</p> <div class="code-example"><div class="example-header"><span class="language-name">scss</span></div><pre class="brush: scss notranslate"><code>// foundation/_index.scss @use "code"; @use "lists"; @use "footer"; @use "links"; </code></pre></div> <p>If the partials are all loaded into an index file, as implied above, you can then load that entire directory into another stylesheet in one go:</p> <div class="code-example"><div class="example-header"><span class="language-name">scss</span></div><pre class="brush: scss notranslate"><code>// style.scss @use "foundation"; </code></pre></div> <div class="notecard note"> <p><strong>Note:</strong> A simple way to try out Sass is to use <a href="https://codepen.io/" class="external" target="_blank">CodePen</a> — you can enable Sass for your CSS in the Settings for a Pen, and CodePen will then run the Sass parser for you in order that you can see the resulting webpage with regular CSS applied. Sometimes you will find that CSS tutorials have used Sass rather than plain CSS in their CodePen demos, so it is handy to know a little bit about it.</p> </div> <h4 id="post-processing_for_optimization">Post-processing for optimization</h4> <p>If you are concerned about adding size to your stylesheets, for example, by adding a lot of additional comments and whitespace, then a post-processing step could be to optimize the CSS by stripping out anything unnecessary in the production version. An example of a post-processor solution for doing this would be <a href="https://cssnano.github.io/cssnano/" class="external" target="_blank">cssnano</a>.</p></div></section><section aria-labelledby="summary"><h2 id="summary"><a href="#summary">Summary</a></h2><div class="section-content"><p>This is the final part of our building blocks module, and as you can see there are many ways in which your exploration of CSS can continue from this point — but now you can go on to testing yourself with our assessments: the first one is linked below.</p> <p>To learn more about layout in CSS, see the <a href="/en-US/docs/Learn/CSS/CSS_layout">CSS Layout</a> module.</p> <p>You should also now have the skills to explore the rest of the <a href="/en-US/docs/Web/CSS">MDN CSS</a> material. You can look up properties and values, explore our <a href="/en-US/docs/Web/CSS/Layout_cookbook">CSS Cookbook</a> for patterns to use, or continue reading in some of the specific guides, such as our <a href="/en-US/docs/Web/CSS/CSS_grid_layout">Guide to CSS grid layout</a>.</p><ul class="prev-next"> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks/Debugging_CSS"><span class="button-wrap"> Previous </span></a></li> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks"><span class="button-wrap"> Overview: CSS building blocks</span></a></li> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension"><span class="button-wrap"> Next </span></a></li> </ul></div></section></article><aside class="article-footer"><div class="article-footer-inner"><div class="svg-container"><svg xmlns="http://www.w3.org/2000/svg" width="162" height="162" viewBox="0 0 162 162" fill="none" role="none"><mask id="b" fill="#fff"><path d="M97.203 47.04c8.113-7.886 18.004-13.871 28.906-17.492a78 78 0 0 1 33.969-3.39c11.443 1.39 22.401 5.295 32.024 11.411s17.656 14.28 23.476 23.86c5.819 9.579 9.269 20.318 10.083 31.385a69.85 69.85 0 0 1-5.387 32.44c-4.358 10.272-11.115 19.443-19.747 26.801-8.632 7.359-18.908 12.709-30.034 15.637l-6.17-21.698c7.666-2.017 14.746-5.703 20.694-10.773 5.948-5.071 10.603-11.389 13.606-18.467a48.14 48.14 0 0 0 3.712-22.352c-.561-7.625-2.938-15.025-6.948-21.625s-9.544-12.226-16.175-16.44-14.181-6.904-22.065-7.863a53.75 53.75 0 0 0-23.405 2.336c-7.513 2.495-14.327 6.62-19.918 12.053z"></path></mask><path stroke="url(#a)" stroke-dasharray="6, 6" stroke-width="2" d="M97.203 47.04c8.113-7.886 18.004-13.871 28.906-17.492a78 78 0 0 1 33.969-3.39c11.443 1.39 22.401 5.295 32.024 11.411s17.656 14.28 23.476 23.86c5.819 9.579 9.269 20.318 10.083 31.385a69.85 69.85 0 0 1-5.387 32.44c-4.358 10.272-11.115 19.443-19.747 26.801-8.632 7.359-18.908 12.709-30.034 15.637l-6.17-21.698c7.666-2.017 14.746-5.703 20.694-10.773 5.948-5.071 10.603-11.389 13.606-18.467a48.14 48.14 0 0 0 3.712-22.352c-.561-7.625-2.938-15.025-6.948-21.625s-9.544-12.226-16.175-16.44-14.181-6.904-22.065-7.863a53.75 53.75 0 0 0-23.405 2.336c-7.513 2.495-14.327 6.62-19.918 12.053z" mask="url(#b)" style="stroke:url(#a)" transform="translate(-63.992 -25.587)"></path><ellipse cx="8.066" cy="111.597" fill="var(--background-tertiary)" rx="53.677" ry="53.699" transform="matrix(.71707 -.697 .7243 .6895 0 0)"></ellipse><g clip-path="url(#c)" transform="translate(-63.992 -25.587)"><path fill="#9abff5" d="m144.256 137.379 32.906 12.434a4.41 4.41 0 0 1 2.559 5.667l-9.326 24.679a4.41 4.41 0 0 1-5.667 2.559l-8.226-3.108-2.332 6.17c-.466 1.233-.375 1.883-1.609 1.417l-2.253-.527c-.411-.155-.95-.594-1.206-1.161l-4.734-10.484-12.545-4.741a4.41 4.41 0 0 1-2.559-5.667l9.325-24.679a4.41 4.41 0 0 1 5.667-2.559m9.961 29.617 8.227 3.108 3.264-8.638-.498-6.768-4.113-1.555.548 7.258-4.319-1.632zm-12.339-4.663 8.226 3.108 3.264-8.637-.498-6.769-4.113-1.554.548 7.257-4.319-1.632z"></path></g><g clip-path="url(#d)" transform="translate(-63.992 -25.587)"><path fill="#81b0f3" d="M135.35 60.136 86.67 41.654c-3.346-1.27-7.124.428-8.394 3.775L64.414 81.938c-1.27 3.347.428 7.125 3.774 8.395l12.17 4.62-3.465 9.128c-.693 1.826-1.432 2.457.394 3.15l3.014 1.625c.609.231 1.637.274 2.477-.104l15.53-6.983 18.56 7.047c3.346 1.27 7.124-.428 8.395-3.775l13.862-36.51c1.27-3.346-.428-7.124-3.775-8.395M95.261 83.207l-12.17-4.62 4.852-12.779 7.19-7.017 6.085 2.31-7.725 7.51 6.389 2.426zm18.255 6.93-12.17-4.62 4.852-12.778 7.189-7.017 6.085 2.31-7.725 7.51 6.39 2.426z"></path></g><defs><clipPath id="c"><path fill="#fff" d="m198.638 146.586-65.056-24.583-24.583 65.057 65.056 24.582z"></path></clipPath><clipPath id="d"><path fill="#fff" d="m66.438 14.055 96.242 36.54-36.54 96.243-96.243-36.54z"></path></clipPath><linearGradient id="a" x1="97.203" x2="199.995" y1="47.04" y2="152.793" gradientUnits="userSpaceOnUse"><stop stop-color="#086DFC"></stop><stop offset="0.246" stop-color="#2C81FA"></stop><stop offset="0.516" stop-color="#5497F8"></stop><stop offset="0.821" stop-color="#80B0F6"></stop><stop offset="1" stop-color="#9ABFF5"></stop></linearGradient></defs></svg></div><h2>Help improve MDN</h2><fieldset class="feedback"><label>Was this page helpful to you?</label><div class="button-container"><button type="button" class="button primary has-icon yes"><span class="button-wrap"><span class="icon icon-thumbs-up "></span>Yes</span></button><button type="button" class="button primary has-icon no"><span class="button-wrap"><span class="icon icon-thumbs-down "></span>No</span></button></div></fieldset><a class="contribute" href="https://github.com/mdn/content/blob/main/CONTRIBUTING.md" title="This will take you to our contribution guidelines on GitHub." target="_blank" rel="noopener noreferrer">Learn how to contribute</a>.<p class="last-modified-date">This page was last modified on <time dateTime="2024-10-25T00:08:46.000Z">Oct 25, 2024</time> by <a href="/en-US/docs/Learn/CSS/Building_blocks/Organizing/contributors.txt" rel="nofollow">MDN contributors</a>.</p><div id="on-github" class="on-github"><a href="https://github.com/mdn/content/blob/main/files/en-us/learn/css/building_blocks/organizing/index.md?plain=1" title="Folder: en-us/learn/css/building_blocks/organizing (Opens in a new tab)" target="_blank" rel="noopener noreferrer">View this page on GitHub</a> • <a href="https://github.com/mdn/content/issues/new?template=page-report.yml&mdn-url=https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FLearn%2FCSS%2FBuilding_blocks%2FOrganizing&metadata=%3C%21--+Do+not+make+changes+below+this+line+--%3E%0A%3Cdetails%3E%0A%3Csummary%3EPage+report+details%3C%2Fsummary%3E%0A%0A*+Folder%3A+%60en-us%2Flearn%2Fcss%2Fbuilding_blocks%2Forganizing%60%0A*+MDN+URL%3A+https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FLearn%2FCSS%2FBuilding_blocks%2FOrganizing%0A*+GitHub+URL%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fblob%2Fmain%2Ffiles%2Fen-us%2Flearn%2Fcss%2Fbuilding_blocks%2Forganizing%2Findex.md%0A*+Last+commit%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fcommit%2Fbaac7f2a43813a7930ff97b11d9c38b413f97c78%0A*+Document+last+modified%3A+2024-10-25T00%3A08%3A46.000Z%0A%0A%3C%2Fdetails%3E" title="This will take you to GitHub to file a new issue." target="_blank" rel="noopener noreferrer">Report a problem with this content</a></div></div></aside></main></div></div><footer id="nav-footer" class="page-footer"><div class="page-footer-grid"><div class="page-footer-logo-col"><a href="/" class="mdn-footer-logo" aria-label="MDN homepage"><svg width="48" height="17" viewBox="0 0 48 17" fill="none" xmlns="http://www.w3.org/2000/svg"><title id="mdn-footer-logo-svg">MDN logo</title><path d="M20.04 16.512H15.504V10.416C15.504 9.488 15.344 8.824 15.024 8.424C14.72 8.024 14.264 7.824 13.656 7.824C12.92 7.824 12.384 8.064 12.048 8.544C11.728 9.024 11.568 9.64 11.568 10.392V14.184H13.008V16.512H8.472V10.416C8.472 9.488 8.312 8.824 7.992 8.424C7.688 8.024 7.232 7.824 6.624 7.824C5.872 7.824 5.336 8.064 5.016 8.544C4.696 9.024 4.536 9.64 4.536 10.392V14.184H6.6V16.512H0V14.184H1.44V8.04H0.024V5.688H4.536V7.32C5.224 6.088 6.32 5.472 7.824 5.472C8.608 5.472 9.328 5.664 9.984 6.048C10.64 6.432 11.096 7.016 11.352 7.8C11.992 6.248 13.168 5.472 14.88 5.472C15.856 5.472 16.72 5.776 17.472 6.384C18.224 6.992 18.6 7.936 18.6 9.216V14.184H20.04V16.512Z" fill="currentColor"></path><path d="M33.6714 16.512H29.1354V14.496C28.8314 15.12 28.3834 15.656 27.7914 16.104C27.1994 16.536 26.4154 16.752 25.4394 16.752C24.0154 16.752 22.8954 16.264 22.0794 15.288C21.2634 14.312 20.8554 12.984 20.8554 11.304C20.8554 9.688 21.2554 8.312 22.0554 7.176C22.8554 6.04 24.0634 5.472 25.6794 5.472C26.5594 5.472 27.2794 5.648 27.8394 6C28.3994 6.352 28.8314 6.8 29.1354 7.344V2.352H26.9754V0H32.2314V14.184H33.6714V16.512ZM29.1354 11.04V10.776C29.1354 9.88 28.8954 9.184 28.4154 8.688C27.9514 8.176 27.3674 7.92 26.6634 7.92C25.9754 7.92 25.3674 8.176 24.8394 8.688C24.3274 9.2 24.0714 10.008 24.0714 11.112C24.0714 12.152 24.3114 12.944 24.7914 13.488C25.2714 14.032 25.8394 14.304 26.4954 14.304C27.3114 14.304 27.9514 13.96 28.4154 13.272C28.8954 12.584 29.1354 11.84 29.1354 11.04Z" fill="currentColor"></path><path d="M47.9589 16.512H41.9829V14.184H43.4229V10.416C43.4229 9.488 43.2629 8.824 42.9429 8.424C42.6389 8.024 42.1829 7.824 41.5749 7.824C40.8389 7.824 40.2709 8.056 39.8709 8.52C39.4709 8.968 39.2629 9.56 39.2469 10.296V14.184H40.6869V16.512H34.7109V14.184H36.1509V8.04H34.5909V5.688H39.2469V7.344C39.9669 6.096 41.1269 5.472 42.7269 5.472C43.7509 5.472 44.6389 5.776 45.3909 6.384C46.1429 6.992 46.5189 7.936 46.5189 9.216V14.184H47.9589V16.512Z" fill="currentColor"></path></svg></a><p>Your blueprint for a better internet.</p><ul class="social-icons"><li><a href="https://mozilla.social/@mdn" target="_blank" rel="me noopener noreferrer"><span class="icon icon-mastodon"></span><span class="visually-hidden">MDN on Mastodon</span></a></li><li><a href="https://twitter.com/mozdevnet" target="_blank" rel="noopener noreferrer"><span class="icon icon-twitter-x"></span><span class="visually-hidden">MDN on X (formerly Twitter)</span></a></li><li><a href="https://github.com/mdn/" target="_blank" rel="noopener noreferrer"><span class="icon icon-github-mark-small"></span><span class="visually-hidden">MDN on GitHub</span></a></li><li><a href="/en-US/blog/rss.xml" target="_blank"><span class="icon icon-feed"></span><span class="visually-hidden">MDN Blog RSS Feed</span></a></li></ul></div><div class="page-footer-nav-col-1"><h2 class="footer-nav-heading">MDN</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a href="/en-US/about">About</a></li><li class="footer-nav-item"><a href="/en-US/blog/">Blog</a></li><li class="footer-nav-item"><a href="https://www.mozilla.org/en-US/careers/listings/?team=ProdOps" target="_blank" rel="noopener noreferrer">Careers</a></li><li class="footer-nav-item"><a href="/en-US/advertising">Advertise with us</a></li></ul></div><div class="page-footer-nav-col-2"><h2 class="footer-nav-heading">Support</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a class="footer-nav-link" href="https://support.mozilla.org/products/mdn-plus">Product help</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/docs/MDN/Community/Issues">Report an issue</a></li></ul></div><div class="page-footer-nav-col-3"><h2 class="footer-nav-heading">Our communities</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/community">MDN Community</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="https://discourse.mozilla.org/c/mdn/236" target="_blank" rel="noopener noreferrer">MDN Forum</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/discord" target="_blank" rel="noopener noreferrer">MDN Chat</a></li></ul></div><div class="page-footer-nav-col-4"><h2 class="footer-nav-heading">Developers</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/docs/Web">Web Technologies</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/docs/Learn">Learn Web Development</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/plus">MDN Plus</a></li><li class="footer-nav-item"><a href="https://hacks.mozilla.org/" target="_blank" rel="noopener noreferrer">Hacks Blog</a></li></ul></div><div class="page-footer-moz"><a href="https://www.mozilla.org/" class="footer-moz-logo-link" target="_blank" rel="noopener noreferrer"><svg width="112" height="32" fill="none" xmlns="http://www.w3.org/2000/svg"><title id="mozilla-footer-logo-svg">Mozilla logo</title><path d="M41.753 14.218c-2.048 0-3.324 1.522-3.324 4.157 0 2.423 1.119 4.286 3.29 4.286 2.082 0 3.447-1.678 3.447-4.347 0-2.826-1.522-4.096-3.413-4.096Zm54.89 7.044c0 .901.437 1.618 1.645 1.618 1.427 0 2.949-1.024 3.044-3.352-.649-.095-1.365-.185-2.02-.185-1.426-.005-2.668.397-2.668 1.92Z" fill="currentColor"></path><path d="M0 0v32h111.908V0H0Zm32.56 25.426h-5.87v-7.884c0-2.423-.806-3.352-2.39-3.352-1.924 0-2.702 1.365-2.702 3.324v4.868h1.864v3.044h-5.864v-7.884c0-2.423-.806-3.352-2.39-3.352-1.924 0-2.702 1.365-2.702 3.324v4.868h2.669v3.044H6.642v-3.044h1.863v-7.918H6.642V11.42h5.864v2.11c.839-1.489 2.3-2.39 4.252-2.39 2.02 0 3.878.963 4.566 3.01.778-1.862 2.361-3.01 4.566-3.01 2.512 0 4.812 1.522 4.812 4.84v6.402h1.863v3.044h-.005Zm9.036.307c-4.314 0-7.296-2.635-7.296-7.106 0-4.096 2.484-7.481 7.514-7.481s7.481 3.38 7.481 7.29c0 4.472-3.228 7.297-7.699 7.297Zm22.578-.307H51.942l-.403-2.11 7.7-8.846h-4.376l-.621 2.17-2.888-.313.498-4.907h12.294l.313 2.11-7.767 8.852h4.533l.654-2.172 3.167.308-.872 4.908Zm7.99 0h-4.191v-5.03h4.19v5.03Zm0-8.976h-4.191v-5.03h4.19v5.03Zm2.618 8.976 6.054-21.358h3.945l-6.054 21.358h-3.945Zm8.136 0 6.048-21.358h3.945l-6.054 21.358h-3.939Zm21.486.307c-1.863 0-2.887-1.085-3.072-2.792-.805 1.427-2.232 2.792-4.498 2.792-2.02 0-4.314-1.085-4.314-4.006 0-3.447 3.323-4.253 6.518-4.253.778 0 1.584.034 2.3.124v-.465c0-1.427-.034-3.133-2.3-3.133-.84 0-1.488.061-2.143.402l-.453 1.578-3.195-.34.549-3.224c2.45-.996 3.692-1.27 5.992-1.27 3.01 0 5.556 1.55 5.556 4.75v6.083c0 .805.314 1.085.963 1.085.184 0 .375-.034.587-.095l.034 2.11a5.432 5.432 0 0 1-2.524.654Z" fill="currentColor"></path></svg></a><ul class="footer-moz-list"><li class="footer-moz-item"><a href="https://www.mozilla.org/privacy/websites/" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Website Privacy Notice</a></li><li class="footer-moz-item"><a href="https://www.mozilla.org/privacy/websites/#cookies" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Cookies</a></li><li class="footer-moz-item"><a href="https://www.mozilla.org/about/legal/terms/mozilla" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Legal</a></li><li class="footer-moz-item"><a href="https://www.mozilla.org/about/governance/policies/participation/" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Community Participation Guidelines</a></li></ul></div><div class="page-footer-legal"><p id="license" class="page-footer-legal-text">Visit <a href="https://www.mozilla.org" target="_blank" rel="noopener noreferrer">Mozilla Corporation’s</a> not-for-profit parent, the <a target="_blank" rel="noopener noreferrer" href="https://foundation.mozilla.org/">Mozilla Foundation</a>.<br/>Portions of this content are ©1998–2024 by individual mozilla.org contributors. Content available under <a href="/en-US/docs/MDN/Writing_guidelines/Attrib_copyright_license">a Creative Commons license</a>.</p></div></div></footer></div><script type="application/json" id="hydration">{"url":"/en-US/docs/Learn/CSS/Building_blocks/Organizing","doc":{"isMarkdown":true,"isTranslated":false,"isActive":true,"flaws":{},"title":"Organizing your CSS","mdn_url":"/en-US/docs/Learn/CSS/Building_blocks/Organizing","locale":"en-US","native":"English (US)","sidebarHTML":"<ol><li class=\"section\"><a href=\"/en-US/docs/Learn/Getting_started_with_the_web\">Complete beginners start here!</a></li><li><details><summary>Getting started with the web</summary><ol><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web\">Getting started with the web</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/Installing_basic_software\">Installing basic software</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/What_will_your_website_look_like\">What will your website look like?</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/Dealing_with_files\">Dealing with files</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/HTML_basics\">HTML basics</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/CSS_basics\">CSS basics</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/JavaScript_basics\">JavaScript basics</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/Publishing_your_website\">Publishing your website</a></li><li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/How_the_Web_works\">How the web works</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/HTML\">HTML — Structuring the web</a></li><li><details><summary>Introduction to HTML</summary><ol><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML\">Introduction to HTML</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Getting_started\">Getting started with HTML</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML\">What's in the head? Metadata in HTML</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/HTML_text_fundamentals\">HTML text fundamentals</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Creating_hyperlinks\">Creating hyperlinks</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Advanced_text_formatting\">Advanced text formatting</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Document_and_website_structure\">Document and website structure</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Debugging_HTML\">Debugging HTML</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter\">Marking up a letter</a></li><li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Structuring_a_page_of_content\">Structuring a page of content</a></li></ol></details></li><li><details><summary>Multimedia and embedding</summary><ol><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding\">Multimedia and embedding</a></li><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Images_in_HTML\">Images in HTML</a></li><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content\">Video and audio content</a></li><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Other_embedding_technologies\">From object to iframe — other embedding technologies</a></li><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Adding_vector_graphics_to_the_Web\">Adding vector graphics to the web</a></li><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images\">Responsive images</a></li><li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Mozilla_splash_page\">Mozilla splash page</a></li></ol></details></li><li><details><summary>HTML tables</summary><ol><li><a href=\"/en-US/docs/Learn/HTML/Tables\">HTML tables</a></li><li><a href=\"/en-US/docs/Learn/HTML/Tables/Basics\">HTML table basics</a></li><li><a href=\"/en-US/docs/Learn/HTML/Tables/Advanced\">HTML table advanced features and accessibility</a></li><li><a href=\"/en-US/docs/Learn/HTML/Tables/Structuring_planet_data\">Structuring planet data</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/CSS\">CSS — Styling the web</a></li><li><details><summary>CSS first steps</summary><ol><li><a href=\"/en-US/docs/Learn/CSS/First_steps\">CSS first steps</a></li><li><a href=\"/en-US/docs/Learn/CSS/First_steps/What_is_CSS\">What is CSS?</a></li><li><a href=\"/en-US/docs/Learn/CSS/First_steps/Getting_started\">Getting started with CSS</a></li><li><a href=\"/en-US/docs/Learn/CSS/First_steps/How_CSS_is_structured\">How CSS is structured</a></li><li><a href=\"/en-US/docs/Learn/CSS/First_steps/How_CSS_works\">How CSS works</a></li><li><a href=\"/en-US/docs/Learn/CSS/First_steps/Styling_a_biography_page\">Styling a biography page</a></li></ol></details></li><li><details open=\"\"><summary>CSS building blocks</summary><ol><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks\">CSS building blocks</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Selectors\">CSS selectors</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors\">Type, class, and ID selectors</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Selectors/Attribute_selectors\">Attribute selectors</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements\">Pseudo-classes and pseudo-elements</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Selectors/Combinators\">Combinators</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Cascade_and_inheritance\">Cascade, specificity, and inheritance</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Cascade_layers\">Cascade layers</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/The_box_model\">The box model</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Backgrounds_and_borders\">Backgrounds and borders</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Handling_different_text_directions\">Handling different text directions</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Overflowing_content\">Overflowing content</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Values_and_units\">CSS values and units</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\">Sizing items in CSS</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Images_media_form_elements\">Images, media, and form elements</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Styling_tables\">Styling tables</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Advanced_styling_effects\">Advanced styling effects</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Debugging_CSS\">Debugging CSS</a></li><li><em><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Organizing\" aria-current=\"page\">Organizing your CSS</a></em></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension\">Fundamental CSS comprehension</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Creating_fancy_letterheaded_paper\">Creating fancy letterheaded paper</a></li><li><a href=\"/en-US/docs/Learn/CSS/Building_blocks/A_cool_looking_box\">A cool-looking box</a></li></ol></details></li><li><details><summary>Styling text</summary><ol><li><a href=\"/en-US/docs/Learn/CSS/Styling_text\">CSS styling text</a></li><li><a href=\"/en-US/docs/Learn/CSS/Styling_text/Fundamentals\">Fundamental text and font styling</a></li><li><a href=\"/en-US/docs/Learn/CSS/Styling_text/Styling_lists\">Styling lists</a></li><li><a href=\"/en-US/docs/Learn/CSS/Styling_text/Styling_links\">Styling links</a></li><li><a href=\"/en-US/docs/Learn/CSS/Styling_text/Web_fonts\">Web fonts</a></li><li><a href=\"/en-US/docs/Learn/CSS/Styling_text/Typesetting_a_homepage\">Typesetting a community school homepage</a></li></ol></details></li><li><details><summary>CSS layout</summary><ol><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout\">CSS layout</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Introduction\">Introduction to CSS layout</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Normal_Flow\">Normal Flow</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Flexbox\">Flexbox</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Grids\">Grids</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Floats\">Floats</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Positioning\">Positioning</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Multiple-column_Layout\">Multiple-column layout</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Responsive_Design\">Responsive design</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Media_queries\">Beginner's guide to media queries</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Legacy_Layout_Methods\">Legacy layout methods</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Supporting_Older_Browsers\">Supporting older browsers</a></li><li><a href=\"/en-US/docs/Learn/CSS/CSS_layout/Fundamental_Layout_Comprehension\">Fundamental layout comprehension</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/JavaScript\">JavaScript — Dynamic client-side scripting</a></li><li><details><summary>JavaScript first steps</summary><ol><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps\">JavaScript first steps</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/What_is_JavaScript\">What is JavaScript?</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/A_first_splash\">A first splash into JavaScript</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/What_went_wrong\">What went wrong? Troubleshooting JavaScript</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/Variables\">Storing the information you need — Variables</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/Math\">Basic math in JavaScript — numbers and operators</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/Strings\">Handling text — strings in JavaScript</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/Useful_string_methods\">Useful string methods</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/Arrays\">Arrays</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/First_steps/Silly_story_generator\">Silly story generator</a></li></ol></details></li><li><details><summary>JavaScript building blocks</summary><ol><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks\">JavaScript building blocks</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/conditionals\">Making decisions in your code — conditionals</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Looping_code\">Looping code</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Functions\">Functions — reusable blocks of code</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Build_your_own_function\">Build your own function</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Return_values\">Function return values</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Events\">Introduction to events</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Event_bubbling\">Event bubbling</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Building_blocks/Image_gallery\">Image gallery</a></li></ol></details></li><li><details><summary>Introducing JavaScript objects</summary><ol><li><a href=\"/en-US/docs/Learn/JavaScript/Objects\">Introducing JavaScript objects</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/Basics\">JavaScript object basics</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/Object_prototypes\">Object prototypes</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/Object-oriented_programming\">Object-oriented programming</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/Classes_in_JavaScript\">Classes in JavaScript</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/JSON\">Working with JSON</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/Object_building_practice\">Object building practice</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Objects/Adding_bouncing_balls_features\">Adding features to our bouncing balls demo</a></li></ol></details></li><li><details><summary>Asynchronous JavaScript</summary><ol><li><a href=\"/en-US/docs/Learn/JavaScript/Asynchronous\">Asynchronous JavaScript</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Asynchronous/Introducing\">Introducing asynchronous JavaScript</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Asynchronous/Promises\">How to use promises</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Asynchronous/Implementing_a_promise-based_API\">How to implement a promise-based API</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Asynchronous/Introducing_workers\">Introducing workers</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Asynchronous/Sequencing_animations\">Sequencing animations</a></li></ol></details></li><li><details><summary>Client-side web APIs</summary><ol><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs\">Client-side web APIs</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Introduction\">Introduction to web APIs</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents\">Manipulating documents</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Fetching_data\">Fetching data from the server</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Third_party_APIs\">Third-party APIs</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Drawing_graphics\">Drawing graphics</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Video_and_audio_APIs\">Video and Audio APIs</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Client-side_storage\">Client-side storage</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/Forms\">Web forms — Working with user data</a></li><li><details><summary>Web form building blocks</summary><ol><li><a href=\"/en-US/docs/Learn/Forms\">Web form building blocks</a></li><li><a href=\"/en-US/docs/Learn/Forms/Your_first_form\">Your first form</a></li><li><a href=\"/en-US/docs/Learn/Forms/How_to_structure_a_web_form\">How to structure a web form</a></li><li><a href=\"/en-US/docs/Learn/Forms/Basic_native_form_controls\">Basic native form controls</a></li><li><a href=\"/en-US/docs/Learn/Forms/HTML5_input_types\">The HTML5 input types</a></li><li><a href=\"/en-US/docs/Learn/Forms/Other_form_controls\">Other form controls</a></li><li><a href=\"/en-US/docs/Learn/Forms/Styling_web_forms\">Styling web forms</a></li><li><a href=\"/en-US/docs/Learn/Forms/Advanced_form_styling\">Advanced form styling</a></li><li><a href=\"/en-US/docs/Learn/Forms/UI_pseudo-classes\">UI pseudo-classes</a></li><li><a href=\"/en-US/docs/Learn/Forms/Form_validation\">Client-side form validation</a></li><li><a href=\"/en-US/docs/Learn/Forms/Sending_and_retrieving_form_data\">Sending form data</a></li></ol></details></li><li><details><summary>Advanced web form techniques</summary><ol><li><a href=\"/en-US/docs/Learn/Forms/How_to_build_custom_form_controls\">How to build custom form controls</a></li><li><a href=\"/en-US/docs/Learn/Forms/Sending_forms_through_JavaScript\">Sending forms through JavaScript</a></li><li><a href=\"/en-US/docs/Learn/Forms/Property_compatibility_table_for_form_controls\">CSS property compatibility table for form controls</a></li><li><a href=\"/en-US/docs/Learn/Forms/HTML_forms_in_legacy_browsers\">HTML forms in legacy browsers</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/Accessibility\">Accessibility — Make the web usable by everyone</a></li><li><details><summary>Accessibility guides</summary><ol><li><a href=\"/en-US/docs/Learn/Accessibility\">Accessibility</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/What_is_accessibility\">What is accessibility?</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/HTML\">HTML: A good basis for accessibility</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/CSS_and_JavaScript\">CSS and JavaScript accessibility best practices</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/WAI-ARIA_basics\">WAI-ARIA basics</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/Multimedia\">Accessible multimedia</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/Mobile\">Mobile accessibility</a></li><li><a href=\"/en-US/docs/Learn/Accessibility/Accessibility_troubleshooting\">Assessment: Accessibility troubleshooting</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/Performance\">Performance — Making websites fast and responsive</a></li><li><details><summary>Performance guides</summary><ol><li><a href=\"/en-US/docs/Learn/Performance\">Web performance</a></li><li><a href=\"/en-US/docs/Learn/Performance/why_web_performance\">The \"why\" of web performance</a></li><li><a href=\"/en-US/docs/Learn/Performance/What_is_web_performance\">What is web performance?</a></li><li><a href=\"/en-US/docs/Learn/Performance/Perceived_performance\">Perceived performance</a></li><li><a href=\"/en-US/docs/Learn/Performance/Measuring_performance\">Measuring performance</a></li><li><a href=\"/en-US/docs/Learn/Performance/Multimedia\">Multimedia: Images</a></li><li><a href=\"/en-US/docs/Learn/Performance/video\">Multimedia: video</a></li><li><a href=\"/en-US/docs/Learn/Performance/JavaScript\">JavaScript performance optimization</a></li><li><a href=\"/en-US/docs/Learn/Performance/HTML\">HTML performance optimization</a></li><li><a href=\"/en-US/docs/Learn/Performance/CSS\">CSS performance optimization</a></li><li><a href=\"/en-US/docs/Learn/Performance/business_case_for_performance\">The business case for web performance</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/MathML\">MathML — Writing mathematics with MathML</a></li><li><details><summary>MathML first steps</summary><ol><li><a href=\"/en-US/docs/Learn/MathML/First_steps\">MathML first steps</a></li><li><a href=\"/en-US/docs/Learn/MathML/First_steps/Getting_started\">Getting started with MathML</a></li><li><a href=\"/en-US/docs/Learn/MathML/First_steps/Text_containers\">MathML Text Containers</a></li><li><a href=\"/en-US/docs/Learn/MathML/First_steps/Fractions_and_roots\">MathML fractions and roots</a></li><li><a href=\"/en-US/docs/Learn/MathML/First_steps/Scripts\">MathML scripted elements</a></li><li><a href=\"/en-US/docs/Learn/MathML/First_steps/Tables\">MathML tables</a></li><li><a href=\"/en-US/docs/Learn/MathML/First_steps/Three_famous_mathematical_formulas\">Three famous mathematical formulas</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/../Games\">Games — Developing games for the web</a></li><li><details><summary>Guides and tutorials</summary><ol><li><a href=\"/en-US/docs/Games/Introduction\">Introduction to game development for the Web</a></li><li><a href=\"/en-US/docs/Games/Techniques\">Techniques for game development</a></li><li><a href=\"/en-US/docs/Games/Tutorials\">Tutorials</a></li><li><a href=\"/en-US/docs/Games/Publishing_games\">Publishing games</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/Tools_and_testing\">Tools and testing</a></li><li><details><summary>Client-side web development tools</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools\">Understanding client-side web development tools</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Overview\">Client-side tooling overview</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Command_line\">Command line crash course</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Package_management\">Package management basics</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Introducing_complete_toolchain\">Introducing a complete toolchain</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Deployment\">Deploying our app</a></li></ol></details></li><li><details><summary>Introduction to client-side frameworks</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Introduction\">Introduction to client-side frameworks</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Main_features\">Framework main features</a></li></ol></details></li><li><details><summary>React</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_getting_started\">Getting started with React</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_todo_list_beginning\">Beginning our React todo list</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_components\">Componentizing our React app</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_events_state\">React interactivity: Events and state</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_filtering_conditional_rendering\">React interactivity: Editing, filtering, conditional rendering</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_accessibility\">Accessibility in React</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_resources\">React resources</a></li></ol></details></li><li><details><summary>Ember</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_getting_started\">Getting started with Ember</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_structure_componentization\">Ember app structure and componentization</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_interactivity_events_state\">Ember interactivity: Events, classes and state</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_conditional_footer\">Ember Interactivity: Footer functionality, conditional rendering</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_routing\">Routing in Ember</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_resources\">Ember resources and troubleshooting</a></li></ol></details></li><li><details><summary>Vue</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_getting_started\">Getting started with Vue</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_first_component\">Creating our first Vue component</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_rendering_lists\">Rendering a list of Vue components</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_methods_events_models\">Adding a new todo form: Vue events, methods, and models</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_styling\">Styling Vue components with CSS</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_computed_properties\">Using Vue computed properties</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_conditional_rendering\">Vue conditional rendering: editing existing todos</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_refs_focus_management\">Vue refs and lifecycle methods for focus management</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_resources\">Vue resources</a></li></ol></details></li><li><details><summary>Svelte</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_getting_started\">Getting started with Svelte</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_Todo_list_beginning\">Starting our Svelte to-do list app</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_variables_props\">Dynamic behavior in Svelte: working with variables and props</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_components\">Componentizing our Svelte app</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_reactivity_lifecycle_accessibility\">Advanced Svelte: Reactivity, lifecycle, accessibility</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_stores\">Working with Svelte stores</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_TypeScript\">TypeScript support in Svelte</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_deployment_next\">Deployment and next steps</a></li></ol></details></li><li><details><summary>Angular</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_getting_started\">Getting started with Angular</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_todo_list_beginning\">Beginning our Angular todo list app</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_styling\">Styling our Angular app</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_item_component\">Creating an item component</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_filtering\">Filtering our to-do items</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_building\">Building Angular applications and further resources</a></li></ol></details></li><li><details><summary>Git and GitHub</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/GitHub\">Git and GitHub</a></li></ol></details></li><li><details><summary>Cross browser testing</summary><ol><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing\">Cross browser testing</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Introduction\">Introduction to cross-browser testing</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Testing_strategies\">Strategies for carrying out testing</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/HTML_and_CSS\">Handling common HTML and CSS problems</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/JavaScript\">Handling common JavaScript problems</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Accessibility\">Handling common accessibility problems</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Feature_detection\">Implementing feature detection</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Automated_testing\">Introduction to automated testing</a></li><li><a href=\"/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Your_own_automation_environment\">Setting up your own test automation environment</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/Server-side\">Server-side website programming</a></li><li><details><summary>First steps</summary><ol><li><a href=\"/en-US/docs/Learn/Server-side/First_steps\">Server-side website programming first steps</a></li><li><a href=\"/en-US/docs/Learn/Server-side/First_steps/Introduction\">Introduction to the server side</a></li><li><a href=\"/en-US/docs/Learn/Server-side/First_steps/Client-Server_overview\">Client-Server Overview</a></li><li><a href=\"/en-US/docs/Learn/Server-side/First_steps/Web_frameworks\">Server-side web frameworks</a></li><li><a href=\"/en-US/docs/Learn/Server-side/First_steps/Website_security\">Website security</a></li></ol></details></li><li><details><summary>Django web framework (Python)</summary><ol><li><a href=\"/en-US/docs/Learn/Server-side/Django\">Django Web Framework (Python)</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Introduction\">Django introduction</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/development_environment\">Setting up a Django development environment</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Tutorial_local_library_website\">Django Tutorial: The Local Library website</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/skeleton_website\">Django Tutorial Part 2: Creating a skeleton website</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Models\">Django Tutorial Part 3: Using models</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Admin_site\">Django Tutorial Part 4: Django admin site</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Home_page\">Django Tutorial Part 5: Creating our home page</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Generic_views\">Django Tutorial Part 6: Generic list and detail views</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Sessions\">Django Tutorial Part 7: Sessions framework</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Authentication\">Django Tutorial Part 8: User authentication and permissions</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Forms\">Django Tutorial Part 9: Working with forms</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Testing\">Django Tutorial Part 10: Testing a Django web application</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/Deployment\">Django Tutorial Part 11: Deploying Django to production</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/web_application_security\">Django web application security</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Django/django_assessment_blog\">Assessment: DIY Django mini blog</a></li></ol></details></li><li><details><summary>Express Web Framework (Node.js/JavaScript)</summary><ol><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs\">Express web framework (Node.js/JavaScript)</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/Introduction\">Express/Node introduction</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/development_environment\">Setting up a Node development environment</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/Tutorial_local_library_website\">Express Tutorial: The Local Library website</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/skeleton_website\">Express Tutorial Part 2: Creating a skeleton website</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/mongoose\">Express Tutorial Part 3: Using a Database (with Mongoose)</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/routes\">Express Tutorial Part 4: Routes and controllers</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/Displaying_data\">Express Tutorial Part 5: Displaying library data</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/forms\">Express Tutorial Part 6: Working with forms</a></li><li><a href=\"/en-US/docs/Learn/Server-side/Express_Nodejs/deployment\">Express Tutorial Part 7: Deploying to production</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn/Common_questions\">Further resources</a></li><li><details><summary>Common questions</summary><ol><li><a href=\"/en-US/docs/Learn/Common_questions\">Common questions</a></li><li><a href=\"/en-US/docs/Learn/HTML/Howto\">Use HTML to solve common problems</a></li><li><a href=\"/en-US/docs/Learn/CSS/Howto\">Use CSS to solve common problems</a></li><li><a href=\"/en-US/docs/Learn/JavaScript/Howto\">Solve common problems in your JavaScript code</a></li><li><a href=\"/en-US/docs/Learn/Common_questions/Web_mechanics\">Web mechanics</a></li><li><a href=\"/en-US/docs/Learn/Common_questions/Tools_and_setup\">Tools and setup</a></li><li><a href=\"/en-US/docs/Learn/Common_questions/Design_and_accessibility\">Design and accessibility</a></li></ol></details></li></ol>","sidebarMacro":"LearnSidebar","body":[{"type":"prose","value":{"id":null,"title":null,"isH3":false,"content":"<ul class=\"prev-next\">\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks/Debugging_CSS\"><span class=\"button-wrap\"> Previous </span></a></li>\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks\"><span class=\"button-wrap\"> Overview: CSS building blocks</span></a></li>\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension\"><span class=\"button-wrap\"> Next </span></a></li>\n</ul>\n<p>As you start to work on larger stylesheets and big projects you will discover that maintaining a huge CSS file can be challenging. In this article we will take a brief look at some best practices for writing your CSS to make it easily maintainable, and some of the solutions you will find in use by others to help improve maintainability.</p>\n<figure class=\"table-container\"><table>\n <tbody>\n <tr>\n <th scope=\"row\">Prerequisites:</th>\n <td>\n <a href=\"/en-US/docs/Learn/Getting_started_with_the_web/Installing_basic_software\">Basic software installed</a>, basic knowledge of\n <a href=\"/en-US/docs/Learn/Getting_started_with_the_web/Dealing_with_files\">working with files</a>, HTML basics (study\n <a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML\">Introduction to HTML</a>), and an idea of how CSS works (study\n <a href=\"/en-US/docs/Learn/CSS/First_steps\">CSS first steps</a>.)\n </td>\n </tr>\n <tr>\n <th scope=\"row\">Objective:</th>\n <td>\n To learn some tips and best practices for organizing stylesheets, and\n find out about some of the naming conventions and tools in common usage\n to help with CSS organization and team working.\n </td>\n </tr>\n </tbody>\n</table></figure>"}},{"type":"prose","value":{"id":"tips_to_keep_your_css_tidy","title":"Tips to keep your CSS tidy","isH3":false,"content":"<p>Here are some general suggestions for ways to keep your stylesheets organized and tidy.</p>"}},{"type":"prose","value":{"id":"does_your_project_have_a_coding_style_guide","title":"Does your project have a coding style guide?","isH3":true,"content":"<p>If you are working with a team on an existing project, the first thing to check is whether the project has an existing style guide for CSS. The team style guide should always win over your own personal preferences. There often isn't a right or wrong way to do things, but consistency is important.</p>\n<p>For example, have a look at the <a href=\"/en-US/docs/MDN/Writing_guidelines/Writing_style_guide/Code_style_guide/CSS\">CSS guidelines for MDN code examples</a>.</p>"}},{"type":"prose","value":{"id":"keep_it_consistent","title":"Keep it consistent","isH3":true,"content":"<p>If you get to set the rules for the project or are working alone, then the most important thing to do is to keep things consistent. Consistency can be applied in all sorts of ways, such as using the same naming conventions for classes, choosing one method of describing color, or maintaining consistent formatting. (For example, will you use tabs or spaces to indent your code? If spaces, how many spaces?)</p>\n<p>Having a set of rules you always follow reduces the amount of mental overhead needed when writing CSS, as some of the decisions are already made.</p>"}},{"type":"prose","value":{"id":"formatting_readable_css","title":"Formatting readable CSS","isH3":true,"content":"<p>There are a couple of ways you will see CSS formatted. Some developers put all of the rules onto a single line, like so:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.box {background-color: #567895; }\nh2 {background-color: black; color: white; }\n</code></pre></div>\n<p>Other developers prefer to break everything onto a new line:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.box {\n background-color: #567895;\n}\n\nh2 {\n background-color: black;\n color: white;\n}\n</code></pre></div>\n<p>CSS doesn't mind which one you use. We personally find it is more readable to have each property and value pair on a new line.</p>"}},{"type":"prose","value":{"id":"comment_your_css","title":"Comment your CSS","isH3":true,"content":"<p>Adding comments to your CSS will help any future developer work with your CSS file, but will also help you when you come back to the project after a break.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>/* This is a CSS comment\nIt can be broken onto multiple lines. */\n</code></pre></div>\n<p>A good tip is to add a block of comments between logical sections in your stylesheet too, to help locate different sections quickly when scanning it, or even to give you something to search for to jump right into that part of the CSS. If you use a string that won't appear in the code, you can jump from section to section by searching for it — below we have used <code>||</code>.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>/* || General styles */\n\n/* … */\n\n/* || Typography */\n\n/* … */\n\n/* || Header and Main Navigation */\n\n/* … */\n</code></pre></div>\n<p>You don't need to comment every single thing in your CSS, as much of it will be self-explanatory. What you should comment are the things where you made a particular decision for a reason.</p>\n<p>You may have used a CSS property in a specific way to get around older browser incompatibilities, for example:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.box {\n background-color: red; /* fallback for older browsers that don't support gradients */\n background-image: linear-gradient(to right, #ff0000, #aa0000);\n}\n</code></pre></div>\n<p>Perhaps you followed a tutorial to achieve something, and the CSS isn't very self-explanatory or recognizable. In that case, you could add the URL of the tutorial to the comments. You will thank yourself when you come back to this project in a year or so and can vaguely remember that there was a great tutorial about that thing, but can't recall where it's from.</p>"}},{"type":"prose","value":{"id":"create_logical_sections_in_your_stylesheet","title":"Create logical sections in your stylesheet","isH3":true,"content":"<p>It is a good idea to have all of the common styling first in the stylesheet. This means all of the styles which will generally apply unless you do something special with that element. You will typically have rules set up for:</p>\n<ul>\n <li><code>body</code></li>\n <li><code>p</code></li>\n <li><code>h1</code>, <code>h2</code>, <code>h3</code>, <code>h4</code>, <code>h5</code></li>\n <li><code>ul</code> and <code>ol</code></li>\n <li>The <code>table</code> properties</li>\n <li>Links</li>\n</ul>\n<p>In this section of the stylesheet we are providing default styling for the type on the site, setting up a default style for data tables and lists and so on.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>/* || GENERAL STYLES */\n\nbody {\n /* … */\n}\n\nh1,\nh2,\nh3,\nh4 {\n /* … */\n}\n\nul {\n /* … */\n}\n\nblockquote {\n /* … */\n}\n</code></pre></div>\n<p>After this section, we could define a few utility classes, for example, a class that removes the default list style for lists we're going to display as flex items or in some other way. If you have a few styling choices you know you will want to apply to lots of different elements, they can be put in this section.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>/* || UTILITIES */\n\n.no-bullets {\n list-style: none;\n margin: 0;\n padding: 0;\n}\n\n/* … */\n</code></pre></div>\n<p>Then we can add everything that is used sitewide. That might be things like the basic page layout, the header, navigation styling, and so on.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>/* SITEWIDE */\n\n.main-nav {\n /* … */\n}\n\n.logo {\n /* … */\n}\n</code></pre></div>\n<p>Finally, we will include CSS for specific things, broken down by the context, page, or even component in which they are used.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>/* || STORE PAGES */\n\n.product-listing {\n /* … */\n}\n\n.product-box {\n /* … */\n}\n</code></pre></div>\n<p>By ordering things in this way, we at least have an idea in which part of the stylesheet we will be looking for something that we want to change.</p>"}},{"type":"prose","value":{"id":"avoid_overly-specific_selectors","title":"Avoid overly-specific selectors","isH3":true,"content":"<p>If you create very specific selectors, you will often find that you need to duplicate chunks of your CSS to apply the same rules to another element. For example, you might have something like the selector below, which applies the rule to a <code><p></code> with a class of <code>box</code> inside an <code><article></code> with a class of <code>main</code>.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>article.main p.box {\n border: 1px solid #ccc;\n}\n</code></pre></div>\n<p>If you then wanted to apply the same rules to something outside of <code>main</code>, or to something other than a <code><p></code>, you would have to add another selector to these rules or create a whole new ruleset. Instead, you could use the selector <code>.box</code> to apply your rule to any element that has the class <code>box</code>:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.box {\n border: 1px solid #ccc;\n}\n</code></pre></div>\n<p>There will be times when making something more specific makes sense; however, this will generally be an exception rather than usual practice.</p>"}},{"type":"prose","value":{"id":"break_large_stylesheets_into_multiple_smaller_ones","title":"Break large stylesheets into multiple smaller ones","isH3":true,"content":"<p>In cases where you have very different styles for distinct parts of the site, you might want to have one stylesheet that includes all the global rules, as well as some smaller stylesheets that include the specific rules needed for those sections. You can link to multiple stylesheets from one page, and the normal rules of the cascade apply, with rules in stylesheets linked later coming after rules in stylesheets linked earlier.</p>\n<p>For example, we might have an online store as part of the site, with a lot of CSS used only for styling the product listings and forms needed for the store. It would make sense to have those things in a different stylesheet, only linked to on store pages.</p>\n<p>This can make it easier to keep your CSS organized, and also means that if multiple people are working on the CSS, you will have fewer situations where two people need to work on the same stylesheet at once, leading to conflicts in source control.</p>"}},{"type":"prose","value":{"id":"other_tools_that_can_help","title":"Other tools that can help","isH3":false,"content":"<p>CSS itself doesn't have much in the way of in-built organization; therefore, the level of consistency in your CSS will largely depend on you. The web community has developed various tools and approaches that can help you to manage larger CSS projects. Since you are likely to come across these aids when working with other people, and since they are often of help generally, we've included a short guide to some of them.</p>"}},{"type":"prose","value":{"id":"css_methodologies","title":"CSS methodologies","isH3":true,"content":"<p>Instead of needing to come up with your own rules for writing CSS, you may benefit from adopting one of the approaches already designed by the community and tested across many projects. These methodologies are essentially CSS coding guides that take a very structured approach to writing and organizing CSS. Typically they tend to render CSS more verbosely than you might have if you wrote and optimized every selector to a custom set of rules for that project.</p>\n<p>However, you do gain a lot of structure by adopting one. Since many of these systems are widely used, other developers are more likely to understand the approach you are using and be able to write their own CSS in the same way, rather than having to work out your own personal methodology from scratch.</p>\n<h4 id=\"oocss\">OOCSS</h4>\n<p>Most of the approaches you will encounter owe something to the concept of Object Oriented CSS (OOCSS), an approach made popular by <a href=\"https://github.com/stubbornella/oocss/wiki\" class=\"external\" target=\"_blank\">the work of Nicole Sullivan</a>. The basic idea of OOCSS is to separate your CSS into reusable objects, which can be used anywhere you need on your site. The standard example of OOCSS is the pattern described as <a href=\"/en-US/docs/Web/CSS/Layout_cookbook/Media_objects\">The Media Object</a>. This is a pattern with a fixed size image, video or other element on one side, and flexible content on the other. It's a pattern we see all over websites for comments, listings, and so on.</p>\n<p>If you are not taking an OOCSS approach you might create a custom CSS for the different places this pattern is used, for example, by creating two classes, one called <code>comment</code> with a bunch of rules for the component parts, and another called <code>list-item</code> with almost the same rules as the <code>comment</code> class except for some tiny differences. The differences between these two components are the list-item has a bottom border, and images in comments have a border whereas list-item images do not.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.comment {\n display: grid;\n grid-template-columns: 1fr 3fr;\n}\n\n.comment img {\n border: 1px solid grey;\n}\n\n.comment .content {\n font-size: 0.8rem;\n}\n\n.list-item {\n display: grid;\n grid-template-columns: 1fr 3fr;\n border-bottom: 1px solid grey;\n}\n\n.list-item .content {\n font-size: 0.8rem;\n}\n</code></pre></div>\n<p>In OOCSS, you would create one pattern called <code>media</code> that would have all of the common CSS for both patterns — a base class for things that are generally the shape of the media object. Then we'd add an additional class to deal with those tiny differences, thus extending that styling in specific ways.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.media {\n display: grid;\n grid-template-columns: 1fr 3fr;\n}\n\n.media .content {\n font-size: 0.8rem;\n}\n\n.comment img {\n border: 1px solid grey;\n}\n\n.list-item {\n border-bottom: 1px solid grey;\n}\n</code></pre></div>\n<p>In your HTML, the comment would need both the <code>media</code> and <code>comment</code> classes applied:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html notranslate\"><code><div class=\"media comment\">\n <img src=\"\" alt=\"\" />\n <div class=\"content\"></div>\n</div>\n</code></pre></div>\n<p>The list-item would have <code>media</code> and <code>list-item</code> applied:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html notranslate\"><code><ul>\n <li class=\"media list-item\">\n <img src=\"\" alt=\"\" />\n <div class=\"content\"></div>\n </li>\n</ul>\n</code></pre></div>\n<p>The work that Nicole Sullivan did in describing this approach and promoting it means that even people who are not strictly following an OOCSS approach today will generally be reusing CSS in this way — it has entered our understanding as a good way to approach things in general.</p>\n<h4 id=\"bem\">BEM</h4>\n<p>BEM stands for Block Element Modifier. In BEM a block is a stand-alone entity such as a button, menu, or logo. An element is something like a list item or a title that is tied to the block it is in. A modifier is a flag on a block or element that changes the styling or behavior. You will be able to recognize code that uses BEM due to the extensive use of dashes and underscores in the CSS classes. For example, look at the classes applied to this HTML from the page about <a href=\"https://getbem.com/naming/\" class=\"external\" target=\"_blank\">BEM Naming conventions</a>:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html notranslate\"><code><form class=\"form form--theme-xmas form--simple\">\n <label class=\"label form__label\" for=\"inputId\"></label>\n <input class=\"form__input\" type=\"text\" id=\"inputId\" />\n\n <input\n class=\"form__submit form__submit--disabled\"\n type=\"submit\"\n value=\"Submit\" />\n</form>\n</code></pre></div>\n<p>The additional classes are similar to those used in the OOCSS example; however, they use the strict naming conventions of BEM.</p>\n<p>BEM is widely used in larger web projects and many people write their CSS in this way. It is likely that you will come across examples, even in tutorials, that use BEM syntax, without mentioning why the CSS is structured in such a way.</p>\n<p>Read more about this system <a href=\"https://css-tricks.com/bem-101/\" class=\"external\" target=\"_blank\">BEM 101</a> on CSS Tricks.</p>\n<h4 id=\"other_common_systems\">Other common systems</h4>\n<p>There are a large number of these systems in use. Other popular approaches include <a href=\"https://smacss.com/\" class=\"external\" target=\"_blank\">Scalable and Modular Architecture for CSS (SMACSS)</a>, created by Jonathan Snook, <a href=\"https://itcss.io/\" class=\"external\" target=\"_blank\">ITCSS</a> from Harry Roberts, and <a href=\"https://acss-io.github.io/atomizer/\" class=\"external\" target=\"_blank\">Atomizer CSS (ACSS)</a>, originally created by Yahoo!. If you come across a project that uses one of these approaches, then the advantage is that you will be able to search and find many articles and guides to help you understand how to code in the same style.</p>\n<p>The disadvantage of using such a system is that they can seem overly complex, especially for smaller projects.</p>"}},{"type":"prose","value":{"id":"build_systems_for_css","title":"Build systems for CSS","isH3":true,"content":"<p>Another way to organize CSS is to take advantage of some of the tooling that is available for front-end developers, which allows you to take a slightly more programmatic approach to writing CSS. There are a number of tools, which we refer to as <em>pre-processors</em> and <em>post-processors</em>. A pre-processor runs over your raw files and turns them into a stylesheet, whereas a post-processor takes your finished stylesheet and does something to it — perhaps to optimize it in order that it will load faster.</p>\n<p>Using any of these tools will require that your development environment be able to run the scripts that do the pre- and post-processing. Many code editors can do this for you, or you can install command line tools to help.</p>\n<p>The most popular pre-processor is <a href=\"https://sass-lang.com/\" class=\"external\" target=\"_blank\">Sass</a>. This is not a Sass tutorial, so I will briefly explain a couple of the things that Sass can do, which are really helpful in terms of organization even if you don't use any of the other Sass features. If you want to learn a lot more about Sass, start with the <a href=\"https://sass-lang.com/guide/\" class=\"external\" target=\"_blank\">Sass basics</a> article, then move on to their other documentation.</p>\n<h4 id=\"defining_variables\">Defining variables</h4>\n<p>CSS now has native <a href=\"/en-US/docs/Web/CSS/Using_CSS_custom_properties\">custom properties</a>, making this feature increasingly less important. However, one of the reasons you might use Sass is to be able to define all of the colors and fonts used in a project as settings, then to use that variable around the project. This means that if you realize you have used the wrong shade of blue, you only need change it in one place.</p>\n<p>If we created a variable called <code>$base-color</code>, as in the first line below, we could then use it through the stylesheet anywhere that required that color.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">scss</span></div><pre class=\"brush: scss notranslate\"><code>$base-color: #c6538c;\n\n.alert {\n border: 1px solid $base-color;\n}\n</code></pre></div>\n<p>Once compiled to CSS, you would end up with the following CSS in the final stylesheet.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>.alert {\n border: 1px solid #c6538c;\n}\n</code></pre></div>\n<h4 id=\"compiling_component_stylesheets\">Compiling component stylesheets</h4>\n<p>I mentioned above that one way to organize CSS is to break down stylesheets into smaller stylesheets. When using Sass you can take this to another level and have lots of very small stylesheets — even going as far as having a separate stylesheet for each component. By using the included functionality in Sass (partials), these can all be compiled together into one or a small number of stylesheets to actually link into your website.</p>\n<p>So, for example, with <a href=\"https://sass-lang.com/documentation/at-rules/use/#partials\" class=\"external\" target=\"_blank\">partials</a>, you could have several style files inside a directory, say <code>foundation/_code.scss</code>, <code>foundation/_lists.scss</code>, <code>foundation/_footer.scss</code>, <code>foundation/_links.scss</code>, etc. You could then use the Sass <code>@use</code> rule to load them into other stylesheets:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">scss</span></div><pre class=\"brush: scss notranslate\"><code>// foundation/_index.scss\n@use \"code\";\n@use \"lists\";\n@use \"footer\";\n@use \"links\";\n</code></pre></div>\n<p>If the partials are all loaded into an index file, as implied above, you can then load that entire directory into another stylesheet in one go:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">scss</span></div><pre class=\"brush: scss notranslate\"><code>// style.scss\n@use \"foundation\";\n</code></pre></div>\n<div class=\"notecard note\">\n <p><strong>Note:</strong> A simple way to try out Sass is to use <a href=\"https://codepen.io/\" class=\"external\" target=\"_blank\">CodePen</a> — you can enable Sass for your CSS in the Settings for a Pen, and CodePen will then run the Sass parser for you in order that you can see the resulting webpage with regular CSS applied. Sometimes you will find that CSS tutorials have used Sass rather than plain CSS in their CodePen demos, so it is handy to know a little bit about it.</p>\n</div>\n<h4 id=\"post-processing_for_optimization\">Post-processing for optimization</h4>\n<p>If you are concerned about adding size to your stylesheets, for example, by adding a lot of additional comments and whitespace, then a post-processing step could be to optimize the CSS by stripping out anything unnecessary in the production version. An example of a post-processor solution for doing this would be <a href=\"https://cssnano.github.io/cssnano/\" class=\"external\" target=\"_blank\">cssnano</a>.</p>"}},{"type":"prose","value":{"id":"summary","title":"Summary","isH3":false,"content":"<p>This is the final part of our building blocks module, and as you can see there are many ways in which your exploration of CSS can continue from this point — but now you can go on to testing yourself with our assessments: the first one is linked below.</p>\n<p>To learn more about layout in CSS, see the <a href=\"/en-US/docs/Learn/CSS/CSS_layout\">CSS Layout</a> module.</p>\n<p>You should also now have the skills to explore the rest of the <a href=\"/en-US/docs/Web/CSS\">MDN CSS</a> material. You can look up properties and values, explore our <a href=\"/en-US/docs/Web/CSS/Layout_cookbook\">CSS Cookbook</a> for patterns to use, or continue reading in some of the specific guides, such as our <a href=\"/en-US/docs/Web/CSS/CSS_grid_layout\">Guide to CSS grid layout</a>.</p><ul class=\"prev-next\">\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks/Debugging_CSS\"><span class=\"button-wrap\"> Previous </span></a></li>\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks\"><span class=\"button-wrap\"> Overview: CSS building blocks</span></a></li>\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension\"><span class=\"button-wrap\"> Next </span></a></li>\n</ul>"}}],"toc":[{"text":"Tips to keep your CSS tidy","id":"tips_to_keep_your_css_tidy"},{"text":"Other tools that can help","id":"other_tools_that_can_help"},{"text":"Summary","id":"summary"}],"summary":"This is the final part of our building blocks module, and as you can see there are many ways in which your exploration of CSS can continue from this point — but now you can go on to testing yourself with our assessments: the first one is linked below.","popularity":0.0313,"modified":"2024-10-25T00:08:46.000Z","other_translations":[{"locale":"de","title":"Organisieren Ihres CSS","native":"Deutsch"},{"locale":"ja","title":"CSS の整理","native":"日本語"},{"locale":"ko","title":"CSS 구성","native":"한국어"},{"locale":"zh-CN","title":"组织 CSS","native":"中文 (简体)"}],"pageType":"learn-module-chapter","source":{"folder":"en-us/learn/css/building_blocks/organizing","github_url":"https://github.com/mdn/content/blob/main/files/en-us/learn/css/building_blocks/organizing/index.md","last_commit_url":"https://github.com/mdn/content/commit/baac7f2a43813a7930ff97b11d9c38b413f97c78","filename":"index.md"},"short_title":"Organizing your CSS","parents":[{"uri":"/en-US/docs/Learn","title":"Guides"},{"uri":"/en-US/docs/Learn/CSS","title":"CSS"},{"uri":"/en-US/docs/Learn/CSS/Building_blocks","title":"CSS building blocks"},{"uri":"/en-US/docs/Learn/CSS/Building_blocks/Organizing","title":"Organizing your CSS"}],"pageTitle":"Organizing your CSS - Learn web development | MDN","noIndexing":false}}</script></body></html>