# Install Arc soft fork
sudo add-apt-repository ppa:fossfreedom/arc-gtk-theme-daily
sudo apt-get install arc-theme
gsettings set org.gnome.desktop.interface gtk-theme 'Arc-Dark'

# https://github.com/nana-4/materia-theme
sudo add-apt-repository ppa:dyatlov-igor/materia-theme
sudo apt install materia-gtk-theme
gsettings set org.gnome.desktop.interface gtk-theme 'Materia-dark-compact'

# https://github.com/daniruiz/flat-remix
sudo add-apt-repository ppa:daniruiz/flat-remix
sudo apt-get install flat-remix
gsettings set org.gnome.desktop.interface icon-theme 'Flat-Remix-Blue-Dark'