This repo contains different stylesheed edited to run with qbittorrent's style system
DarkStyleSheet theme is based on https://github.com/ColinDuquesnoy/QDarkStyleSheet
Mumble themes are based on https://github.com/mumble-voip/mumble-theme
Breeze themes are based on https://github.com/Alexhuszagh/BreezeStyleSheets
Icons used in dark themes are from nowshed-imran. They are meant to be icons for next qbittorrent major release (https://github.com/qbittorrent/qBittorrent/pull/12965). Do give your opinions on the thread :)
This repo also contains different tool to create your own qbittorrent theme files.
You can check the source of above style in