This PR aims to:

 - Fix some general issues;
 - Remove glitches happening during resizing;
 - Make better use of available space on tablets & mobiles;
 - More accessible TOC table;
 - Fix navigation issues for tablets, and;
 - Remove commented out CSS code.

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Merge pull request #5153 from ostezer/mkdocs-fix-for-nav-4-tablets

Fixes and ameliorations for the new MkDocs theme.