Gainsight supports css on guide and template levels. However there are multiple css selectors that are not accessible or can’t be customized, for example, 1) triangle (which points to the aligned element) from the engagement guide takes the background color and can’t be hidden using css (No. it doesn’t take transparent color as background); 2) a drop shadow on .apt-guide-popup level remains visible and can’t be customized even after turning off shadow in Settings.
There are also css attributes that are cross templates (e.g., font-family, default text/link color) which need to be set/repeated in every template.
Having capability to access/customize global css would help solving these limitations.