A CSS framework is a software library allowing for easier, more standards-compliant web design using Cascading Style Sheets. Most of these frameworks contain at least a grid. More functional frameworks also come with more features and additional JavaScript based functions, but are mostly design oriented and focused around interactive UI patterns. This detail differentiates CSS frameworks from other JavaScript frameworks.
Two notable and widely used examples are Bootstrap and Foundation.
Modules and tools offered by CSS frameworks include:
reset style sheet grid, especially for responsive web design web typography set of icons in sprites or icon fonts styling for tooltips, buttons, elements of forms parts of graphical user interfaces such as accordion, tabs, slideshow or modal windows (Lightbox) equalizer to create equal height content often-used CSS helper classes (left, hide)
Bigger frameworks use a CSS interpreter such as Less or Sass.
List of notable CSS frameworks
Name Latest release License Grid Units Features of columns version date Blueprint 1.0.1 May 14, 2011 Typography, forms, print, plugins for buttons, tabs, and sprites. Bootstrap 5.3.8 August 26, 2025 fixed, fluid, responsive px, % Layout, typography, forms, buttons, navigation, media queries, .sass files, JavaScript libraries, RTL layout. ,default 12Bootstrap documentation - Customizing the gridBulma1.0.4April 19, 2025MIT Licenseflexbox, CSS grid, responsiverem, px, %, CSS variablesLayout, typography, forms, buttons, navigation, responsive columns, CSS gridAny Foundation 6.9.0 September 28, 2024 fluid px, % Responsive layout, source ordering, typography, forms, buttons, navigation, media queries, and JavaScript libraries. ,default 12Foundation documentation - The GridUI Kit3.25.21August 7, 2026MIT Licenseflexbox, responsivepx, %, vw, remLayout, grids, typography, forms, buttons, navigation, cards, modals, animations, responsive utils, componentsAny YAML 4.1.2 July 28, 2013 fixed, elastic, fluid px, em, % Layout, grids, columns, forms, buttons, progressive linearization for responsive layouts, float handling, navigation, typography, accessibility, and add-ons. (accessible tabs, RTL-support, and microformats) YUI CSS grids 3.18.1 October 22, 2014 -3 fixed and fluidTailwind 4.3.0 May 09, 2026 fixed, fluid, responsive
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