Skeuos is a GTK application theme inspired by the latest skeumorphic design trends, by embracing the bevels, drop-shadows, and gradients most modern themes actively avoid.
But as you can see those button images are not PNG's having a transparent background. So if the panel has a bit of transparency it looks very weird. It is even more weird with the light theme version:
I think this could be solved if those button images for XFWM would have a transparent background. If you tell me what files to edit maybe I can help you with this.
This is a bit more of a special case but is meant to improve this theme. So, in XFCE I can install this plugin https://gitlab.xfce.org/panel-plugins/xfce4-windowck-plugin and have the window buttons on a panel. Like so:
But as you can see those button images are not PNG's having a transparent background. So if the panel has a bit of transparency it looks very weird. It is even more weird with the light theme version:
I think this could be solved if those button images for XFWM would have a transparent background. If you tell me what files to edit maybe I can help you with this.
Thanks!