Small improvements to the mobile interface

[elegaanz]

• The overflowing header bug seems to be fixed. Fixes Content area and menu overflow past their border on mobile in the new theme #652
• There are now small margins everywhere (no more big margins, no more non-existent margins, and this on every page (article, editors, home, etc)). Fixes Margins are too narrow on mobile #655 and the second point of Mobile UX issues #604
• The "header" of the advanced editor is now more easily usable (fix for this comment: Mobile UX issues #604 (comment))

cc @marek-lach tell me if this works for you.

[codecov]

Codecov Report

Merging #663 into main will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #663      +/-   ##
==========================================
- Coverage   39.02%   38.98%   -0.04%     
==========================================
  Files          73       73              
  Lines        9777     9777              
  Branches     2240     2240              
==========================================
- Hits         3815     3812       -3     
  Misses       4906     4906              
- Partials     1056     1059       +3     

[elegaanz]

I deployed this branch to https://baptiste.gelez.xyz because for some reason Plume CI failed…

[Aldarone]

Would be nice if a touch on the burger menu button closed it back when it's open.

[igalic]

Would be nice if a touch on the burger menu button closed it back when it's open.

i did say that when @AnaGelez was designing this the first time around…