With how node.js influenced frontend dev is those days, looking for
index files is good way to start. The entry file to Misago's styles lies here. To customize your CSS you'll need to clone Misago's frontend somewhere and edit
var misago to point to
theme directory is created together with rest of files when you run
startmisago.py, but you'll need to create
misago dir within
Once this is done, you can run
gulp watchstyle that will watch less files for changes and will rebuilt
theme/static/misago/css/style.css if any of them change. If you are pleased with results, run
gulp style which will build minified
style.css that you may deploy on production. If you want to add static files like images, you may drop them in
theme/static as well and they will work too.
I'm currently working for default theme for Misago, and eventually I'll love to improve and document process of writing custom themes for forums, but for now cloning and modifying frontend is best option.