Fixes regression
https://github.com/go-gitea/gitea/pull/31307#issuecomment-2162554913
Table CSS is weird. A `auto` value does not work and causes the
regression while any pixel value causes another regression in diff where
the code lines do not stretch. Partially revert that PR and clean up
some related too-deep CSS selectors.
<img width="109" alt="Screenshot 2024-06-12 at 15 07 22"
src="756c5dea-44b8-49f9-8a08-acef68075f62">
<img width="119" alt="Screenshot 2024-06-12 at 15 07 43"
src="28ae1adc-118e-4016-8d09-033b9f1c9a6f">
<img width="151" alt="Screenshot 2024-06-12 at 15 07 07"
src="08db7ed9-de4e-405e-874d-c7ebe3082557">
<img width="141" alt="Screenshot 2024-06-12 at 15 07 14"
src="c4a5492b-1bf1-4773-bc8d-64eb36d823f9">