Timewarrior uses color, and supports color themes. The colors are used for assorted highlighting, and for coloring tags on charts. Themes are optional, but can improve your experience.
To use a theme, you need a line added to your
~/.timewarrior/timewarrior.cfg file, like this:
That path is platform-dependent, so yours may differ.
There are four themes included in the release:
Consider making your own and sharing.