Hi Christoph,

Based on Totara 2.9 the CSS setting variable replacement names you're looking for are generated by combining the theme setting names:

'linkcolor'
'linkvisitedcolor'
'headerbgc'
'buttoncolor'

with each of the following suffixes:

'lighter'
'darker'
'light'
'dark'
'lighter-perc'
'darker-perc'
'light-perc'
'dark-perc'
'readable-text'
'readable-text-shadow'

You will find these listed in the following file / functions:

theme/customtotararesponsive/lib.php theme_customtotararesponsive_process_css()

and

totara/core/totara.php totara_theme_generate_autocolors()

Let me know if you have any further questions.

Cheers,

Joby