To allow easier theming #3942 we have migrated to using LESS for CSS. This was done as part of pull request: #88
This allows easier refactor and reuse of colors, fonts, etc.
Fixed in git, available in Piwik 2
In a1cfa04: Refs #4052 Reprocess CSS file if any of merged files has changed
NOTE: does not support @import'ed less files, could be added in prepareMergedCssFile @diosmosis
Refs #4052 Reprocess CSS file if any of merged files has changed