Oxygen-Gtk3 is a port of the default KDE widget theme (Oxygen), to gtk 3.x.

It's primary goal is to ensure visual consistency between gtk-based and qt-based
applications running under KDE. A secondary objective is to also have a
stand-alone nice looking gtk theme that would behave well on other Desktop
Environments.

Unlike other attempts made to port the KDE oxygen theme to gtk, this attempt does
not depend on Qt (via some Qt to Gtk conversion engine), nor does render the
widget appearance via hard coded pixmaps, which otherwise breaks everytime some
setting is changed in KDE.