History: CSS Overview
Preview of version: 5
Presentation
The presentation of elements, the visual style of your theme, is created using CSS (Cascading Style Sheets).
W3C provides tutorials and other tools for learning CSS principles: www.w3.org/Style/CSS. See also the CSS links in the Directory.
Tiki methodologies
You can either start with an existing theme style sheet and copy, rename and modify it, or you can start with a "blank" CSS file and create the new style from scratch. To start from an existing CSS file, see Modifying an Existing Style Sheet; to start from a blank CSS file, see Starting Fresh — CSS.