Colours for project/global variables in manage pages should be in CSS.

This allows style to define a theme, as opposed to using a configuration
variable for something that will not normally be seen.

40f4e288db69afcaffb754a01c1077cb7d08ac4e
Shouldn't we use "color" since it is the common approach to write it in programming languages?  This should eventually apply for the related $s_, but at least we shouldn't introduce new ones.