Clay CSS is the web implementation of Liferay’s Experience Language. This is a system for building applications in and outside of Liferay, designed to be fluid and extensible, as well as provide a consistent and documented API.
Clay CSS is based on Bootstrap 4.4.1. You will find Bootstrap's and Clay CSS' API to be very similar because Clay CSS was created to fill the gaps between Bootstrap's and Liferay's UI as well as providing familiarity to new devs joining the Liferay ecosystem.
Clay CSS is shipped with two flavors,
Atlas Theme. The Base Theme is bundled with
frontend-theme-styled in Liferay Portal. Atlas Theme is our flagship theme that is bundled with
The Base Theme provides a familiar starting point to develop your own custom theme by preserving default Bootstrap styles such as colors and sizing. It contains all CSS rulesets for both themes. You can toggle Base Theme by clicking the cog icon inside the top right nav.
|-- Functions |-- Base Variables |-- Mixins |-- SCSS
Atlas Theme is a set of Sass variables that are applied on top of the Base Theme. The variables change everything from colors to sizing and spacing. No additional rulesets are required. This allows us to reuse a CSS ruleset instead of having to duplicate and overwrite it in
frontend-theme-classic, saving us from CSS bloat.
|-- Functions |-- Atlas Variables |-- Base Variables |-- Mixins |-- SCSS
Clay CSS is installed during build time in Liferay Portal. There is a placeholder file
clay.scss where Clay CSS should be imported. This file is included inside the
head tag as an external stylesheet in Portal.
If you are using Liferay Theme Tasks to deploy your theme, you can see the contents of
your-theme/build/_css/clay.scss. If you are extending the Styled Theme,
clay.scss should contain
@import clay/base; and Classic Theme should have
@import clay/atlas;. You can view the Clay CSS source in
You can switch between Base and Atlas Theme at any time by creating a file
your-theme/src/css/clay.scss and importing Base or Atlas. This will overwrite the default
clay.scss file used by Portal.
Customizing Clay CSS
Liferay Portal provides a placeholder file
_clay_variables.scss and imports it at the top of
atlas.scss. This file should contain all your Clay CSS Sass Variable overwrites. You can change the primary color to red by creating a new file named
your-theme/src/css/_clay_variables.scss and adding the line
$primary: red;. Clay CSS has thousands of customization options that gives you full control over the styles of each component.
Adding CSS Rulesets to Clay CSS
You can add CSS rulesets to the
clay.scss file by creating a file called
_clay_custom.scss in the
_clay_custom.scss is imported at the bottom of