Fix source code viewer background color when using Dark Mode in Diffusion
Summary:
This CSS fix replaces the hard coded white background value by the diff.background CSS variable. This is a proposal
to address this issue but it may be a good idea to create a different CSS variable (for instance source.background)
in order to avoid any potential side effect in the future.
| Before | After |
|---|---|
 |  |
Fix : T15056
Test Plan:
- Flush all Phorge caches
- Sign in
- Open a diffusion repository
- Open any file
- Check that viewer background color is consistent with the theme.
Reviewers: O1 Blessed Committers, valerio.bozzolan
Reviewed By: O1 Blessed Committers, valerio.bozzolan
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Differential Revision: https://we.phorge.it/D25396