How change colours of a theme

[pgr]

It’s been discussed often here, for example

Simple CSS Override

I think the mention of JS injection is leading you guys in a needlessly complex direction. If you just add that snippet of CSS into a file called custom/themes/SuiteP/css/Dawn/style.css it will get appended to your styles. Make sure to change that Dawn for the specific sub-theme you’re using. Or create 4 separate files, one for each sub-theme.

That’s for the simple styling tweaks.

And that post linked a couple of posts above is the most complete tutorial for a full custom theme creation.