One of the strong points of GNU/Linux is the ability to easily change the look of the desktop environment.

I created this page because you pointed out that "it might be better to make the decoration a little more neat".
One of the characteristics of UVGL is its simplicity, so we don't customise it more than necessary. Please introduce a theme that suits your taste.
You can download it from here, here and more.

LXQt

Place the LXQt theme in "/usr/share/lxqt/themes" and the Openbox theme in "/usr/share/themes". The former can be changed from "Settings" → "LXQt settings" → "Appearance settings" → "LXQt Theme", and the latter can be changed from "Settings" → "Openbox Settings" → "Theme".

Xfce

Since it is a GTK theme, please place it in "/usr/share/theme". You can change the desktop from "Settings" → "Appearance", and the window manager from "Settings" → "Window Manager Tweaks" → "Style".