Table of Contents

To get oxygen appearance in GTK apps

Install the gtk oxygen engines and kde config style

gtk2-engines-oxygen
gtk3-engines-oxygen
kde-config-gtk-style

Start system settings app

Go to Application appearance
Select GTK and then choose the oxygen-gtk theme's for both gtk2 and gtk3
Select Oxygen Icon theme

To get Breeze appearance in GTK apps

Start system settings app

Go to Application Style
Select GTK and then choose the Breeze theme's for both gtk2 and gtk3
Select Breeze Cursor theme
Select Breeze Icon theme
Uncheck “Left mouse warps scroll bar” (had to toggle this to get it working)