For this ticket as the change might be really small in term of difference (tint of colors ...), best is to just have a check on the generated theme/boost/style/moodle.css Copy the diff-theme-css.php script to the root of your moodle folder run  git checkout main git pull git checkout - # Goes back to the current branch which should be MDL-81816-main git diff main theme /boost/style/moodle .css > MDL-81816.css. diff go to <siteurl>/diff-theme-css.php Ensure there is no visible difference between original colors and the new ones. Additionally check a couple of pages: You can check mostly on the course page where text is close / closer to the background color (you can check that you have at least a 4.5:1 ratio on https://accessibleweb.com/color-contrast-checker/ ) Go into a course and edit in line any activity Check that the edit instruction are contrasted enough with the text. If you have a doubt look for 'span.editinstructions' in the theme/moodle.css file and check the background color vs text color contrast. Go to a course with some activities Open the contextual menu and select the "Availability" item Ensure that there is sufficient contrast between the selected option and the text color