From the document https://docs.google.com/document/d/1ZnSQ4B216CNROHvzXgRwe2SuoJH9MikcxByXYVQm1z8/edit?ts=59cbd4e8#heading=h.fj5km28jcr9a Change H1 settings as recommended CSS h1: font-size: 22pt, border-bottom: 3px solid #18A303; margin-bottom: 10px File to touch: https://opengrok.libreoffice.org/xref/help/help3xsl/default.css
Adolfo Jayme Barrientos committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/help/commit/?id=208b4ffb21e49ad906280ce3663852d5a1b83994 tdf#112754 Enlarge H1, make its fonts thinner & increase margin-bottom
I complied, but with a couple of tweaks: • 22-px bold looked too large to me, so I’ve added “font-weight: 300” • I noticed the margin-bottom rule was duplicated unnecessarily, so I’ve settled on 8 px for its global value. We should consider making this change to the offline help CSS files as well.