The following rules must be followed:

• The HTML output produced by XWiki pages must be valid XHTML.
• The XWiki project is also following the W3C WCAG Guidelines. In addition we're also following the Dutch Web Guidelines which are even stricter than the WCAG ones.

CSS

The following rules must be followed:

• the CSS must be valid conform CSS 2.1 specification. This can be tested using the W3C CSS Validator
• don't use inline style declarations
• don't hard code colors in properties - use ColorTheme attributes
• test your code on at least 3 browsers (IE, FF, Safari)

The following recommendations could be followed:

• Properties:
  • alphabetical order
  • 2 spaces indentation
  • use of CSS shorthands
  • use relative sizes (em, %) instead of fixed ones (px)
  • use appropriate CSS files for writing IE rules
    • limit as much as possible the number of IE hacks used
• Organization:
  • comment headers for separation and grouping of different parts of the code
• Overwriting:
  • document the localization of the overwrite using "Overwrites" and "Should be in" comments

Issues

• We currently don't have a naming convention

Tools

• Firebug
• CSS Optimizer and CSS Compressor are two excellent online tools that can shrink CSS

Testing

See the Testing page.