Primer CSS Details Last Updated : 28 May, 2025 Comments Improve Suggest changes Like Article Like Report Primer CSS is a free open-source CSS framework that is built upon a GitHub design system to provide support to the broad spectrum of GitHub websites. It creates the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by Object-Oriented CSS principles, functional CSS, and BEM architecture. It is a highly reusable model.Primer CSS Details Classes are made in order to improve the behavior of the default HTML Details component.Primer CSS Details Classes:Fullscreen click area: The .details-overlay class is used to add to the <details> tag to expand the click area to the whole page. This means the user can click anywhere on the page to close the opened details tag.Darkened fullscreen click area: The .details-overlay-dark class is used to add to the <details> tag to make its background dark.Custom caret: The .details-reset class when added to the <details> tag, removes the default caret placed on the left of the details. We can then add our custom caret after using this class to the <details> tag.Using button styles with the details summary element: The .dropdown-caret class is used to add a dropdown caret icon to the <details>.Syntax:<details class="DetailsClass"> <summary class="..">..</summary></details>Example 1: In this example, we have created a simple detail with a dropdown caret icon in the summary. HTML <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href= "https://unpkg.com/@primer/css@^18.0.0/dist/primer.css" /> <title>Primer CSS Details</title> </head> <body> <h1 style="color: green;"> GeeksforGeeks </h1> <h3>Primer CSS Details</h3> <div class="m-2"> <details class="details-overlay"> <summary class="btn btn-primary"> Click Me <span class="dropdown-caret"></span> </summary> <div class="border p-3 mt-2"> This is the sample text that will be shown when the "Click Me" text is clicked. </div> </details> </div> </body> </html> Output: Example 2: In this example, we have created a detail with a dark overlay. It means that whenever we clicked, the background becomes dark. HTML <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href= "https://unpkg.com/@primer/css@^18.0.0/dist/primer.css" /> <title>Primer CSS Details</title> </head> <body> <h1 style="color: green;">GeeksforGeeks</h1> <h3>Primer CSS Details</h3> <div class="m-2"> <details class="details-overlay details-overlay-dark"> <summary class="btn btn-primary"> Click Me</summary> <div class="border p-3 mt-2"> This is the sample text that will be shown when the "Click Me" text is clicked. </div> </details> </div> </body> </html> Output: Comment More infoAdvertise with us Next Article Primer CSS Flexbox S saikatmohanta43434 Follow Improve Article Tags : Web Technologies CSS Primer-CSS Primer-CSS Utilities Similar Reads Primer CSS Primer CSS is a free open-source CSS framework built with the GitHub design system to support the broad spectrum of Github websites. 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Created with GitHub’s design system, it is highly reusable and flexible. Primer CSS Blankslate is used as a placeholder when 5 min read Primer CSS Box OverlayPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 2 min read Primer CSS Branch namePrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 2 min read Primer CSS BreadcrumbsPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. It is highly reusable and flexible. It is created with GitHub’s design system.Primer CSS offers us so many components, and Breadcru 2 min read Primer CSS ButtonsPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 2 min read Primer CSS DropdownPrimer CSS is a free and open-source CSS framework that is built using the GitHub design system for providing support to the broad spectrum of GitHub websites. It helps in creating the foundation of the basic style elements such as spacing, components, typography, color, etc.Dropdowns are lightweigh 4 min read Primer CSS FormsPrimer CSS is a free and open-source CSS framework. It is built upon the systems that create the foundation of the basic style elements such as spacing, typography, and color. Created with GitHub’s design system, it is highly reusable and flexible.Primer CSS Forms provide different components for in 6 min read Primer CSS HeaderPrimer CSS is a free open-source CSS framework that is built upon a GitHub design system to provide support to the broad spectrum of GitHub websites. It creates the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are stead 3 min read Primer CSS LabelsPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 3 min read Primer CSS LinksPrimer CSS is a free and open-source CSS framework. It is built upon the systems that create the foundation of the basic style elements such as spacing, typography, and colour. Created with GitHub’s design system, it is highly reusable and flexible.Primer CSS Links are used to decorate links in the 3 min read Primer CSS LoadersPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 2 min read Primer CSS MarkdownPrimer CSS is a free open-source CSS framework built with the GitHub design system to support the broad spectrum of Github websites. It creates the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure that our patterns are steady and intero 3 min read Primer CSS NavigationPrimer CSS is a free open-source CSS framework that is formed upon systems that establish the foundation of the basic style elements such as spacing, typography, and color. 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It creates the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are ste 4 min read Primer CSS Select menuPrimer CSS is a free open-source CSS framework built on principles that establish the foundation for basic design elements including spacing, typeface, and color. Our patterns will be consistent and compatible as a result of this method. Its CSS approach is influenced by object-oriented CSS concepts 4 min read Primer CSS SubheadPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 2 min read Primer CSS TimelinePrimer CSS is a free open-source CSS framework that is built upon the GitHub design system to provide support to the broad spectrum of Github websites. It creates the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are ste 7 min read Primer CSS ToastsPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 3 min read Primer CSS TruncatePrimer CSS is a CSS framework that comes with pre-styled components and a design language with spacing, typography, and Theming that helps in building a website effectively. This systematic method makes sure our patterns are steady and interoperable with every other. It is created with GitHub’s desi 2 min read Primer CSS MarketingPrimer CSS Marketing ButtonsPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. It is highly reusable and flexible. It is created with GitHub’s design system.Buttons are used to define an action that can be perf 2 min read Primer CSS Marketing FiltersPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. It is highly reusable and flexible. It is created with GitHub’s design system.Filters are used to change the overall background or 2 min read Primer CSS Marketing LinksPrimer CSS is a free open-source CSS framework that is built upon systems that create the foundation of the basic style elements such as spacing, typography, and color. This systematic method makes sure our patterns are steady and interoperable with every other. Its approach to CSS is influenced by 2 min read Primer CSS Marketing TypographyTypography is a feature of Primer for styling and formatting the text content. It is used to create headings, subheadings, paragraphs, pull quotes, add more design-oriented font styles, and much more. It's responsive, but on a smaller scale, and the headlines are set in the marketing typeface.Primer 3 min read Like