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:

Bigger frameworks use a CSS interpreter such as Less or Sass.

List of notable CSS frameworks

NameLatest releaseLicenseGridUnitsFeaturesNo. of columns
versiondate
Blueprint1.0.1May 14, 2011MIT LicenseTypography, forms, print, plugins for buttons, tabs, and sprites.
Bootstrap5.3.3February 20, 2024MIT License (Apache License prior to 3.1.0)fixed, fluid, responsivepx, %Layout, typography, forms, buttons, navigation, media queries, .sass files, JavaScript libraries, RTL layout.Any, default 12
Foundation6.7.5July 13, 2022MIT Licensefluidpx, %Responsive layout, source ordering, typography, forms, buttons, navigation, media queries, and JavaScript libraries.Any, default 12
YAML4.1.2July 28, 2013CC-BY 2.0fixed, elastic, fluidpx, 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)Any
YUI CSS grids3.18.1October 22, 2014BSD-3fixed and fluid
Tailwind3.4.3March 27, 2024MIT Licensefixed, fluid, responsiveAny