How to download and setup qt-stylesheets
Open terminal and run command
                                            git clone https://github.com/xakod/qt-stylesheets.git
                                        
                                        git clone is used to create a copy or clone of qt-stylesheets repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with qt-stylesheets https://github.com/xakod/qt-stylesheets/archive/master.zip
Or simply clone qt-stylesheets with SSH
                                            [email protected]:xakod/qt-stylesheets.git                                    
                                    If you have some problems with qt-stylesheets
You may open issue on qt-stylesheets support forum (system) here: https://github.com/xakod/qt-stylesheets/issuesSimilar to qt-stylesheets repositories
Here you may see qt-stylesheets alternatives and analogs
openage tiled liteide qt qutebrowser MuseScore mapbox-gl-native qTox Clementine antimony flameshot gqrx mixxx appleseed pywebview toggldesktop edb-debugger openauto CuteMarkEd LibreCAD qgroundcontrol otter-browser feedback QDarkStyleSheet stellarium hotspot GoldenCheetah SlicerGitSVNArchive qtbase nitroshare-desktop