Layan is a flat Material Design theme for GTK 3, GTK 2 and Gnome-Shell which supports GTK 3 and GTK 2 based desktop environments like Gnome, Budgie, etc.
This theme is based on materia gtk theme of nana-4. Thanks nana-4 sincerely for his great job!
yum install gtk-murrine-engine gtk2-engines
sudo apt-get install gtk2-engines-murrine gtk2-engines-pixbuf
pacman -S gtk-engine-murrine gtk-engines
Other:Search for the engines in your distributions repository or install the engines from source.
Open the terminal at current directory.
git clone vinceliuice-Layan-gtk-theme_-_2019-11-07_06-15-04.bundle