Styling with SLD and CSS

This section introduces the concepts of the Styled Layer Descriptor (SLD) markup language.
SLD is the styling engine used by GeoServer, and how all WMS portrayal is specified.
In this section you will also use the CSS extension module that allows you to build map styles using a compact, expressive styling language already well known to most web developers: Cascading Style Sheets.
The standard CSS language has been extended to allow for map filtering and managing all the details of a map production. The examples will have styles in SLD and CSS language.

In the official GeoServer documentation you can find useful references as the SLD Cookbook and the CSS Cookbook.