It would be nice to if you can use your own css. Off course you can make changes in qa.css etc. But if a newer version from bitbucket is used these changes will be undone.
Proposal: Load 'qa-institute.css' after the original QATrack+ qa.css file. This file then shouldn't be in the respository but created by the users institute.
css files: qa.css --> qa-institute.css charts.css --> charts-institute.css