When I did a stylesheet something BeeLine-esque for Calibre, I did something similar for the text fill gradient (<a href="https:&#x2F;&#x2F;gist.github.com&#x2F;osuushi&#x2F;6461324" rel="nofollow">https:&#x2F;&#x2F;gist.github.com&#x2F;osuushi&#x2F;6461324</a>)