Install breeze by entering the following commands in the terminal:
sudo apt update sudo apt install breeze
Description:
Default Plasma theme (meta-package).
This is the default theme for the KDE Plasma desktop. . This package includes wallpapers, icons, cursors, KWin style and Qt widget style for the Plasma 5 desktop. . This package is part of the KDE base workspace module.
Homepage: https://projects.kde.org/projects/kde/workspace/breeze
Version: 4:5.12.4-0ubuntu1
Section: universe/kde