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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><em><a href="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" aria-current="page">Sizing items in CSS</a></em></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><a href="/en-US/docs/Learn/CSS/Building_blocks/Organizing">Organizing your CSS</a></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="#the_natural_or_intrinsic_size_of_things">The natural or intrinsic size of things</a></li><li class="document-toc-item "><a class="document-toc-link" href="#setting_a_specific_size">Setting a specific size</a></li><li class="document-toc-item "><a class="document-toc-link" href="#min-_and_max-_sizes">min- and max- sizes</a></li><li class="document-toc-item "><a class="document-toc-link" href="#viewport_units">Viewport units</a></li><li class="document-toc-item "><a class="document-toc-link" href="#test_your_skills!">Test your skills!</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>Sizing items in CSS</h1></header><div class="section-content"><ul class="prev-next"> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks/Values_and_units"><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/Images_media_form_elements"><span class="button-wrap"> Next </span></a></li> </ul> <p>In the various lessons so far, you have come across a number of ways to size items on a web page using CSS. Understanding how big the different features in your design will be is important. So, in this lesson we will summarize the various ways elements get a size via CSS and define a few terms about sizing that will help you in the future.</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 understand the different ways we can size things in CSS.</td> </tr> </tbody> </table></figure></div><section aria-labelledby="the_natural_or_intrinsic_size_of_things"><h2 id="the_natural_or_intrinsic_size_of_things"><a href="#the_natural_or_intrinsic_size_of_things">The natural or intrinsic size of things</a></h2><div class="section-content"><p>HTML Elements have a natural size, set before they are affected by any CSS. A straightforward example is an image. An image file contains sizing information, described as its <strong>intrinsic size</strong>. This size is determined by the image <em>itself</em>, not by any formatting we happen to apply.</p> <p>If you place an image on a page and do not change its height or width, either by using attributes on the <code><img></code> tag or else by CSS, it will be displayed using that intrinsic size. We have given the image in the example below a border so that you can see the extent of its size as defined in its file.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___intrinsic-image notranslate"><code><img alt="star" src="https://mdn.github.io/shared-assets/images/examples/big-star.png" /> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___intrinsic-image notranslate"><code>img { border: 5px solid darkblue; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="intrinsic-image sample" id="frame_intrinsic-image" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="intrinsic-image" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>An empty <a href="/en-US/docs/Web/HTML/Element/div"><code><div></code></a>, on the other hand, has no size of its own. If you add a <a href="/en-US/docs/Web/HTML/Element/div"><code><div></code></a> to your HTML with no content, then give it a border as we did with the image, you will see a line on the page. This is the collapsed border on the element — there is no content to hold it open. In our example below, that border stretches to the width of the container, because it is a block level element, a behavior that should be starting to become familiar to you. It has no height (or size in the block dimension) because there is no content.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___intrinsic-text notranslate"><code><div class="box"></div> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___intrinsic-text notranslate"><code>.box { border: 5px solid darkblue; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="intrinsic-text sample" id="frame_intrinsic-text" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="intrinsic-text" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>In the example above, try adding some text inside the empty element. The border now contains that text because the height of the element is defined by the content. Therefore the size of this <code><div></code> in the block dimension comes from the size of the content. Again, this is the intrinsic size of the element — its size is defined by its content.</p></div></section><section aria-labelledby="setting_a_specific_size"><h2 id="setting_a_specific_size"><a href="#setting_a_specific_size">Setting a specific size</a></h2><div class="section-content"><p>We can, of course, give elements in our design a specific size. When a size is given to an element (the content of which then needs to fit into that size) we refer to it as an <strong>extrinsic size</strong>. Take our <code><div></code> from the example above — we can give it specific <a href="/en-US/docs/Web/CSS/width"><code>width</code></a> and <a href="/en-US/docs/Web/CSS/height"><code>height</code></a> values, and it will now have that size no matter what content is placed into it. As we discovered in <a href="/en-US/docs/Learn/CSS/Building_blocks/Overflowing_content">our previous lesson on overflow</a>, a set height can cause content to overflow if there is more content than the element has space to fit inside it.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___height notranslate"><code><div class="wrapper"> <div class="box"></div> <div class="box"> These boxes both have a height set, this box has content in it which will need more space than the assigned height, and so we get overflow. </div> </div> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___height notranslate"><code>body { font: 1.2em sans-serif; } .wrapper { display: flex; } .wrapper > * { margin: 20px; } .box { border: 5px solid darkblue; height: 100px; width: 200px; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="height sample" id="frame_height" height="200px" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="height" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>Due to this problem of overflow, fixing the height of elements with lengths or percentages is something we need to do very carefully on the web.</p></div></section><section aria-labelledby="using_percentages"><h3 id="using_percentages"><a href="#using_percentages">Using percentages</a></h3><div class="section-content"><p>In many ways, percentages act like length units, and as we <a href="/en-US/docs/Learn/CSS/Building_blocks/Values_and_units#percentages">discussed in the lesson on values and units</a>, they can often be used interchangeably with lengths. When using a percentage you need to be aware what it is a percentage <em>of</em>. In the case of a box inside another container, if you give the child box a percentage width it will be a percentage of the width of the parent container.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___percent-width notranslate"><code><div class="box">I have a percentage width.</div> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___percent-width notranslate"><code>body { font: 1.2em sans-serif; } .box { border: 5px solid darkblue; width: 50%; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="percent-width sample" id="frame_percent-width" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="percent-width" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>This is because percentages resolve against the size of the containing block. With no percentage applied, our <code><div></code> would take up 100% of the available space, as it is a block level element. If we give it a percentage width, this becomes a percentage of the space it would normally fill.</p></div></section><section aria-labelledby="percentage_margins_and_padding"><h3 id="percentage_margins_and_padding"><a href="#percentage_margins_and_padding">Percentage margins and padding</a></h3><div class="section-content"><p>If you set <code>margins</code> and <code>padding</code> as a percentage, you may notice some strange behavior. In the below example we have a box. We have given the inner box a <a href="/en-US/docs/Web/CSS/margin"><code>margin</code></a> of 10% and a <a href="/en-US/docs/Web/CSS/padding"><code>padding</code></a> of 10%. The padding and margin on the top and bottom of the box are the same size as the padding and margin on the left and right.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___percent-mp notranslate"><code><div class="box">I have margin and padding set to 10% on all sides.</div> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___percent-mp notranslate"><code>body { font: 1.2em sans-serif; } .box { border: 5px solid darkblue; width: 200px; margin: 10%; padding: 10%; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="percent-mp sample" id="frame_percent-mp" height="380px" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="percent-mp" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>You might expect for example the percentage top and bottom margins to be a percentage of the element's height, and the percentage left and right margins to be a percentage of the element's width. However, this is not the case!</p> <p>When you use margin and padding set in percentages, the value is calculated from the <strong>inline size</strong> of the containing block — therefore the width when working in a horizontal language. In our example, all of the margins and padding are 10% of the width. This means you can have equal-sized margins and padding all around the box. This is a fact worth remembering if you do use percentages in this way.</p></div></section><section aria-labelledby="min-_and_max-_sizes"><h2 id="min-_and_max-_sizes"><a href="#min-_and_max-_sizes">min- and max- sizes</a></h2><div class="section-content"><p>In addition to giving things a fixed size, we can ask CSS to give an element a minimum or a maximum size. If you have a box that might contain a variable amount of content, and you always want it to be <em>at least</em> a certain height, you could set the <a href="/en-US/docs/Web/CSS/min-height"><code>min-height</code></a> property on it. The box will always be at least this height, but will then grow taller if there is more content than the box has space for at its minimum height.</p> <p>In the example below you can see two boxes, both with a defined <code>min-height</code> of 100 pixels. The box on the left is 100 pixels tall; the box on the right has content that needs more room, and so it has grown taller than 100 pixels.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___min-height notranslate"><code><div class="wrapper"> <div class="box"></div> <div class="box"> These boxes both have a min-height set, this box has content in it which will need more space than the assigned height, and so it grows from the minimum. </div> </div> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___min-height notranslate"><code>body { font: 1.2em sans-serif; } .wrapper { display: flex; align-items: flex-start; } .wrapper > * { margin: 20px; } .box { border: 5px solid darkblue; min-height: 100px; width: 200px; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="min-height sample" id="frame_min-height" height="220px" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="min-height" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>This is very useful for dealing with variable amounts of content while avoiding overflow.</p> <p>A common use of <a href="/en-US/docs/Web/CSS/max-width"><code>max-width</code></a> is to cause images to scale down if there is not enough space to display them at their intrinsic width while making sure they don't become larger than that width.</p> <p>As an example, if you were to set <code>width: 100%</code> on an image, and its intrinsic width was smaller than its container, the image would be forced to stretch and become larger, causing it to look pixelated.</p> <p>If you instead use <code>max-width: 100%</code>, and its intrinsic width is smaller than its container, the image will not be forced to stretch and become larger, thus preventing pixelation.</p> <p>In the example below, we have used the same image three times. The first image has been given <code>width: 100%</code> and is in a container which is larger than it, therefore it stretches to the container width. The second image has <code>max-width: 100%</code> set on it and therefore does not stretch to fill the container. The third box contains the same image again, also with <code>max-width: 100%</code> set; in this case you can see how it has scaled down to fit into the box.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___max-width notranslate"><code><div class="wrapper"> <div class="box"> <img alt="star" class="width" src="https://mdn.github.io/shared-assets/images/examples/big-star.png" /> </div> <div class="box"> <img alt="star" class="max" src="https://mdn.github.io/shared-assets/images/examples/big-star.png" /> </div> <div class="mini-box"> <img alt="star" class="max" src="https://mdn.github.io/shared-assets/images/examples/big-star.png" /> </div> </div> </code></pre></div> <div class="code-example"><pre class="brush: css hidden live-sample___max-width notranslate"><code>.wrapper { display: flex; align-items: flex-start; } .wrapper > * { margin: 20px; } .box, .mini-box { border: 5px solid darkblue; } </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___max-width notranslate"><code>.box { width: 200px; } .mini-box { width: 50px; } .width { width: 100%; } .max { max-width: 100%; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="max-width sample" id="frame_max-width" height="260px" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="max-width" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>This technique is used to make images <em>responsive</em>, so that when viewed on a smaller device they scale down appropriately. You should, however, not use this technique to load really large images and then scale them down in the browser. Images should be appropriately sized to be no larger than they need to be for the largest size they are displayed in the design. Downloading overly large images will cause your site to become slow, and it can cost users more money if they are on a metered connection.</p> <div class="notecard note"> <p><strong>Note:</strong> Find out more about <a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images">responsive image techniques</a>.</p> </div></div></section><section aria-labelledby="viewport_units"><h2 id="viewport_units"><a href="#viewport_units">Viewport units</a></h2><div class="section-content"><p>The viewport — which is the visible area of your page in the browser you are using to view a site — also has a size. In CSS we have units which relate to the size of the viewport — the <code>vw</code> unit for viewport width, and <code>vh</code> for viewport height. Using these units you can size something relative to the viewport of the user.</p> <p><code>1vh</code> is equal to 1% of the viewport height, and <code>1vw</code> is equal to 1% of the viewport width. You can use these units to size boxes, but also text. In the example below we have a box which is sized as 20vh and 20vw. The box contains a letter <code>A</code>, which has been given a <a href="/en-US/docs/Web/CSS/font-size"><code>font-size</code></a> of 10vh.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html live-sample___vw-vh notranslate"><code><div class="box">A</div> </code></pre></div> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css live-sample___vw-vh notranslate"><code>body { font-family: sans-serif; } .box { border: 5px solid darkblue; width: 20vw; height: 20vh; font-size: 10vh; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="vw-vh sample" id="frame_vw-vh" src="about:blank" data-live-path="/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS" data-live-id="vw-vh" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>If you change the <code>vh</code> and <code>vw</code> values this will change the size of the box or font; changing the viewport size will also change their sizes because they are sized relative to the viewport. To see the example change when you change the viewport size you will need to load the example in a new browser window that you can resize (as the embedded <code><iframe></code> that contains the example shown above is its viewport). Open the example, resize the browser window, and observe what happens to the size of the box and text.</p> <p>Sizing things according to the viewport can be useful in your designs. For example, if you want a full-page hero section to show before the rest of your content, making that part of your page 100vh high will push the rest of the content below the viewport, meaning that it will only appear once the document is scrolled.</p></div></section><section aria-labelledby="test_your_skills!"><h2 id="test_your_skills!"><a href="#test_your_skills!">Test your skills!</a></h2><div class="section-content"><p>You've reached the end of this article, but can you remember the most important information? You can find some further tests to verify that you've retained this information before you move on — see <a href="/en-US/docs/Learn/CSS/Building_blocks/Sizing_tasks">Test your skills: Sizing</a>.</p></div></section><section aria-labelledby="summary"><h2 id="summary"><a href="#summary">Summary</a></h2><div class="section-content"><p>This lesson has given you a rundown of some key issues that you might run into when sizing things on the web. When you move onto <a href="/en-US/docs/Learn/CSS/CSS_layout">CSS Layout</a>, sizing will become very important in mastering the different layout methods, so it is worth understanding the concepts here before moving on.</p> <p>In the next article, we'll take a look at how <a href="/en-US/docs/Learn/CSS/Building_blocks/Images_media_form_elements">images, media, and form elements</a> are treated in CSS.</p><ul class="prev-next"> <li><a class="button secondary" href="/en-US/docs/Learn/CSS/Building_blocks/Values_and_units"><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/Images_media_form_elements"><span class="button-wrap"> Next </span></a></li> </ul></div></section></article><aside class="article-footer"><div class="article-footer-inner"><div 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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><em><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" aria-current=\"page\">Sizing items in CSS</a></em></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><a href=\"/en-US/docs/Learn/CSS/Building_blocks/Organizing\">Organizing your CSS</a></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/Values_and_units\"><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/Images_media_form_elements\"><span class=\"button-wrap\"> Next </span></a></li>\n</ul>\n<p>In the various lessons so far, you have come across a number of ways to size items on a web page using CSS. Understanding how big the different features in your design will be is important. So, in this lesson we will summarize the various ways elements get a size via CSS and define a few terms about sizing that will help you in the future.</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>To understand the different ways we can size things in CSS.</td>\n </tr>\n </tbody>\n</table></figure>"}},{"type":"prose","value":{"id":"the_natural_or_intrinsic_size_of_things","title":"The natural or intrinsic size of things","isH3":false,"content":"<p>HTML Elements have a natural size, set before they are affected by any CSS. A straightforward example is an image. An image file contains sizing information, described as its <strong>intrinsic size</strong>. This size is determined by the image <em>itself</em>, not by any formatting we happen to apply.</p>\n<p>If you place an image on a page and do not change its height or width, either by using attributes on the <code><img></code> tag or else by CSS, it will be displayed using that intrinsic size. We have given the image in the example below a border so that you can see the extent of its size as defined in its file.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___intrinsic-image notranslate\"><code><img\n alt=\"star\"\n src=\"https://mdn.github.io/shared-assets/images/examples/big-star.png\" />\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___intrinsic-image notranslate\"><code>img {\n border: 5px solid darkblue;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"intrinsic-image sample\" id=\"frame_intrinsic-image\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"intrinsic-image\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>An empty <a href=\"/en-US/docs/Web/HTML/Element/div\"><code><div></code></a>, on the other hand, has no size of its own. If you add a <a href=\"/en-US/docs/Web/HTML/Element/div\"><code><div></code></a> to your HTML with no content, then give it a border as we did with the image, you will see a line on the page. This is the collapsed border on the element — there is no content to hold it open. In our example below, that border stretches to the width of the container, because it is a block level element, a behavior that should be starting to become familiar to you. It has no height (or size in the block dimension) because there is no content.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___intrinsic-text notranslate\"><code><div class=\"box\"></div>\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___intrinsic-text notranslate\"><code>.box {\n border: 5px solid darkblue;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"intrinsic-text sample\" id=\"frame_intrinsic-text\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"intrinsic-text\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>In the example above, try adding some text inside the empty element. The border now contains that text because the height of the element is defined by the content. Therefore the size of this <code><div></code> in the block dimension comes from the size of the content. Again, this is the intrinsic size of the element — its size is defined by its content.</p>"}},{"type":"prose","value":{"id":"setting_a_specific_size","title":"Setting a specific size","isH3":false,"content":"<p>We can, of course, give elements in our design a specific size. When a size is given to an element (the content of which then needs to fit into that size) we refer to it as an <strong>extrinsic size</strong>. Take our <code><div></code> from the example above — we can give it specific <a href=\"/en-US/docs/Web/CSS/width\"><code>width</code></a> and <a href=\"/en-US/docs/Web/CSS/height\"><code>height</code></a> values, and it will now have that size no matter what content is placed into it. As we discovered in <a href=\"/en-US/docs/Learn/CSS/Building_blocks/Overflowing_content\">our previous lesson on overflow</a>, a set height can cause content to overflow if there is more content than the element has space to fit inside it.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___height notranslate\"><code><div class=\"wrapper\">\n <div class=\"box\"></div>\n <div class=\"box\">\n These boxes both have a height set, this box has content in it which will\n need more space than the assigned height, and so we get overflow.\n </div>\n</div>\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___height notranslate\"><code>body {\n font: 1.2em sans-serif;\n}\n.wrapper {\n display: flex;\n}\n\n.wrapper > * {\n margin: 20px;\n}\n\n.box {\n border: 5px solid darkblue;\n height: 100px;\n width: 200px;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"height sample\" id=\"frame_height\" height=\"200px\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"height\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>Due to this problem of overflow, fixing the height of elements with lengths or percentages is something we need to do very carefully on the web.</p>"}},{"type":"prose","value":{"id":"using_percentages","title":"Using percentages","isH3":true,"content":"<p>In many ways, percentages act like length units, and as we <a href=\"/en-US/docs/Learn/CSS/Building_blocks/Values_and_units#percentages\">discussed in the lesson on values and units</a>, they can often be used interchangeably with lengths. When using a percentage you need to be aware what it is a percentage <em>of</em>. In the case of a box inside another container, if you give the child box a percentage width it will be a percentage of the width of the parent container.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___percent-width notranslate\"><code><div class=\"box\">I have a percentage width.</div>\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___percent-width notranslate\"><code>body {\n font: 1.2em sans-serif;\n}\n\n.box {\n border: 5px solid darkblue;\n width: 50%;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"percent-width sample\" id=\"frame_percent-width\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"percent-width\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>This is because percentages resolve against the size of the containing block. With no percentage applied, our <code><div></code> would take up 100% of the available space, as it is a block level element. If we give it a percentage width, this becomes a percentage of the space it would normally fill.</p>"}},{"type":"prose","value":{"id":"percentage_margins_and_padding","title":"Percentage margins and padding","isH3":true,"content":"<p>If you set <code>margins</code> and <code>padding</code> as a percentage, you may notice some strange behavior. In the below example we have a box. We have given the inner box a <a href=\"/en-US/docs/Web/CSS/margin\"><code>margin</code></a> of 10% and a <a href=\"/en-US/docs/Web/CSS/padding\"><code>padding</code></a> of 10%. The padding and margin on the top and bottom of the box are the same size as the padding and margin on the left and right.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___percent-mp notranslate\"><code><div class=\"box\">I have margin and padding set to 10% on all sides.</div>\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___percent-mp notranslate\"><code>body {\n font: 1.2em sans-serif;\n}\n.box {\n border: 5px solid darkblue;\n width: 200px;\n margin: 10%;\n padding: 10%;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"percent-mp sample\" id=\"frame_percent-mp\" height=\"380px\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"percent-mp\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>You might expect for example the percentage top and bottom margins to be a percentage of the element's height, and the percentage left and right margins to be a percentage of the element's width. However, this is not the case!</p>\n<p>When you use margin and padding set in percentages, the value is calculated from the <strong>inline size</strong> of the containing block — therefore the width when working in a horizontal language. In our example, all of the margins and padding are 10% of the width. This means you can have equal-sized margins and padding all around the box. This is a fact worth remembering if you do use percentages in this way.</p>"}},{"type":"prose","value":{"id":"min-_and_max-_sizes","title":"min- and max- sizes","isH3":false,"content":"<p>In addition to giving things a fixed size, we can ask CSS to give an element a minimum or a maximum size. If you have a box that might contain a variable amount of content, and you always want it to be <em>at least</em> a certain height, you could set the <a href=\"/en-US/docs/Web/CSS/min-height\"><code>min-height</code></a> property on it. The box will always be at least this height, but will then grow taller if there is more content than the box has space for at its minimum height.</p>\n<p>In the example below you can see two boxes, both with a defined <code>min-height</code> of 100 pixels. The box on the left is 100 pixels tall; the box on the right has content that needs more room, and so it has grown taller than 100 pixels.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___min-height notranslate\"><code><div class=\"wrapper\">\n <div class=\"box\"></div>\n <div class=\"box\">\n These boxes both have a min-height set, this box has content in it which\n will need more space than the assigned height, and so it grows from the\n minimum.\n </div>\n</div>\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___min-height notranslate\"><code>body {\n font: 1.2em sans-serif;\n}\n.wrapper {\n display: flex;\n align-items: flex-start;\n}\n\n.wrapper > * {\n margin: 20px;\n}\n\n.box {\n border: 5px solid darkblue;\n min-height: 100px;\n width: 200px;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"min-height sample\" id=\"frame_min-height\" height=\"220px\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"min-height\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>This is very useful for dealing with variable amounts of content while avoiding overflow.</p>\n<p>A common use of <a href=\"/en-US/docs/Web/CSS/max-width\"><code>max-width</code></a> is to cause images to scale down if there is not enough space to display them at their intrinsic width while making sure they don't become larger than that width.</p>\n<p>As an example, if you were to set <code>width: 100%</code> on an image, and its intrinsic width was smaller than its container, the image would be forced to stretch and become larger, causing it to look pixelated.</p>\n<p>If you instead use <code>max-width: 100%</code>, and its intrinsic width is smaller than its container, the image will not be forced to stretch and become larger, thus preventing pixelation.</p>\n<p>In the example below, we have used the same image three times. The first image has been given <code>width: 100%</code> and is in a container which is larger than it, therefore it stretches to the container width. The second image has <code>max-width: 100%</code> set on it and therefore does not stretch to fill the container. The third box contains the same image again, also with <code>max-width: 100%</code> set; in this case you can see how it has scaled down to fit into the box.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___max-width notranslate\"><code><div class=\"wrapper\">\n <div class=\"box\">\n <img\n alt=\"star\"\n class=\"width\"\n src=\"https://mdn.github.io/shared-assets/images/examples/big-star.png\" />\n </div>\n <div class=\"box\">\n <img\n alt=\"star\"\n class=\"max\"\n src=\"https://mdn.github.io/shared-assets/images/examples/big-star.png\" />\n </div>\n <div class=\"mini-box\">\n <img\n alt=\"star\"\n class=\"max\"\n src=\"https://mdn.github.io/shared-assets/images/examples/big-star.png\" />\n </div>\n</div>\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: css hidden live-sample___max-width notranslate\"><code>.wrapper {\n display: flex;\n align-items: flex-start;\n}\n\n.wrapper > * {\n margin: 20px;\n}\n\n.box,\n.mini-box {\n border: 5px solid darkblue;\n}\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___max-width notranslate\"><code>.box {\n width: 200px;\n}\n.mini-box {\n width: 50px;\n}\n.width {\n width: 100%;\n}\n.max {\n max-width: 100%;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"max-width sample\" id=\"frame_max-width\" height=\"260px\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"max-width\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>This technique is used to make images <em>responsive</em>, so that when viewed on a smaller device they scale down appropriately. You should, however, not use this technique to load really large images and then scale them down in the browser. Images should be appropriately sized to be no larger than they need to be for the largest size they are displayed in the design. Downloading overly large images will cause your site to become slow, and it can cost users more money if they are on a metered connection.</p>\n<div class=\"notecard note\">\n <p><strong>Note:</strong> Find out more about <a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images\">responsive image techniques</a>.</p>\n</div>"}},{"type":"prose","value":{"id":"viewport_units","title":"Viewport units","isH3":false,"content":"<p>The viewport — which is the visible area of your page in the browser you are using to view a site — also has a size. In CSS we have units which relate to the size of the viewport — the <code>vw</code> unit for viewport width, and <code>vh</code> for viewport height. Using these units you can size something relative to the viewport of the user.</p>\n<p><code>1vh</code> is equal to 1% of the viewport height, and <code>1vw</code> is equal to 1% of the viewport width. You can use these units to size boxes, but also text. In the example below we have a box which is sized as 20vh and 20vw. The box contains a letter <code>A</code>, which has been given a <a href=\"/en-US/docs/Web/CSS/font-size\"><code>font-size</code></a> of 10vh.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html live-sample___vw-vh notranslate\"><code><div class=\"box\">A</div>\n</code></pre></div>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css live-sample___vw-vh notranslate\"><code>body {\n font-family: sans-serif;\n}\n\n.box {\n border: 5px solid darkblue;\n width: 20vw;\n height: 20vh;\n font-size: 10vh;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"vw-vh sample\" id=\"frame_vw-vh\" src=\"about:blank\" data-live-path=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\" data-live-id=\"vw-vh\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>If you change the <code>vh</code> and <code>vw</code> values this will change the size of the box or font; changing the viewport size will also change their sizes because they are sized relative to the viewport. To see the example change when you change the viewport size you will need to load the example in a new browser window that you can resize (as the embedded <code><iframe></code> that contains the example shown above is its viewport). Open the example, resize the browser window, and observe what happens to the size of the box and text.</p>\n<p>Sizing things according to the viewport can be useful in your designs. For example, if you want a full-page hero section to show before the rest of your content, making that part of your page 100vh high will push the rest of the content below the viewport, meaning that it will only appear once the document is scrolled.</p>"}},{"type":"prose","value":{"id":"test_your_skills!","title":"Test your skills!","isH3":false,"content":"<p>You've reached the end of this article, but can you remember the most important information? You can find some further tests to verify that you've retained this information before you move on — see <a href=\"/en-US/docs/Learn/CSS/Building_blocks/Sizing_tasks\">Test your skills: Sizing</a>.</p>"}},{"type":"prose","value":{"id":"summary","title":"Summary","isH3":false,"content":"<p>This lesson has given you a rundown of some key issues that you might run into when sizing things on the web. When you move onto <a href=\"/en-US/docs/Learn/CSS/CSS_layout\">CSS Layout</a>, sizing will become very important in mastering the different layout methods, so it is worth understanding the concepts here before moving on.</p>\n<p>In the next article, we'll take a look at how <a href=\"/en-US/docs/Learn/CSS/Building_blocks/Images_media_form_elements\">images, media, and form elements</a> are treated in CSS.</p><ul class=\"prev-next\">\n <li><a class=\"button secondary\" href=\"/en-US/docs/Learn/CSS/Building_blocks/Values_and_units\"><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/Images_media_form_elements\"><span class=\"button-wrap\"> Next </span></a></li>\n</ul>"}}],"toc":[{"text":"The natural or intrinsic size of things","id":"the_natural_or_intrinsic_size_of_things"},{"text":"Setting a specific size","id":"setting_a_specific_size"},{"text":"min- and max- sizes","id":"min-_and_max-_sizes"},{"text":"Viewport units","id":"viewport_units"},{"text":"Test your skills!","id":"test_your_skills!"},{"text":"Summary","id":"summary"}],"summary":"This lesson has given you a rundown of some key issues that you might run into when sizing things on the web. When you move onto CSS Layout, sizing will become very important in mastering the different layout methods, so it is worth understanding the concepts here before moving on.","popularity":0.0078,"modified":"2024-11-11T09:53:21.000Z","other_translations":[{"locale":"de","title":"Größe von Elementen in CSS","native":"Deutsch"},{"locale":"es","title":"Dimensionar elementos en CSS","native":"Español"},{"locale":"fr","title":"Définir la taille des éléments en CSS","native":"Français"},{"locale":"ja","title":"CSS によるサイズ設定","native":"日本語"},{"locale":"ko","title":"CSS 에서 항목 크기 조정","native":"한국어"},{"locale":"ru","title":"Изменение размеров в CSS","native":"Русский"},{"locale":"zh-CN","title":"在 CSS 中调整大小","native":"中文 (简体)"}],"pageType":"learn-module-chapter","source":{"folder":"en-us/learn/css/building_blocks/sizing_items_in_css","github_url":"https://github.com/mdn/content/blob/main/files/en-us/learn/css/building_blocks/sizing_items_in_css/index.md","last_commit_url":"https://github.com/mdn/content/commit/14f294a447447b484ec1589636d04af1a5794288","filename":"index.md"},"short_title":"Sizing items in 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/Sizing_items_in_CSS","title":"Sizing items in CSS"}],"pageTitle":"Sizing items in CSS - Learn web development | MDN","noIndexing":false}}</script></body></html>