The Howtos I've seen for how to do this have been a bit... long and unfocused. Here's the TLDR.
Install
qt5ct
Optionally install
kvantum
Set the following in ~/.profile
Code:
export QT_QPA_PLATFORMTHEME=qt5ct
Reboot
You'll be able to start "Qt5 Settings" and use it to your Qt "Style", fonts and icons. If you've installed Kvantum, then you'll see it in the list of Styles and you can start "Kvantum Manager" to set it up.
I recommend starting with Breeze for both the Style and Icons, and setting the font to be consistent with the GTK desktop. That should look good with most setups.
