Minor Description of problem:
The 404 error page uses the same background color as the sidebar menu
Prerequisites (if any, like setup, operators/versions):
Steps to Reproduce
Just change URL to so random endpoint to get 404 error page
Actual results:
Visual difference is not there between sidebar menu and page content
Expected results:
404 error page should use same background color as main page content
Reproducibility (Always/Intermittent/Only Once):
Always
