Indent guides not visible

Tested this with Catppuccin Mocha. Indent guides are not visible, it seems it is tied to the css class `.ace_indent-guide` as reported in RStudio User Guide https://docs.posit.co/ide/user/ide/guide/ui/appearance.html#creating-an-rstheme. It seems this class is not in the rstheme file, hence when changing the options from Global Options > Code > Display > Indentation guides nothing happens

Locate the RStudio .rstheme files and check whether the `.ace_indent-guide` class is defined. Reproduce the issue using Catppuccin Mocha and the Indentation guides setting; done means the guides become visible when that option is enabled.

Written by the indexing model from the issue text.