Arc Gtk Theme customized for Ubuntu 16.04!
su
apt install git gnome-themes-standard gtk2-engines-murrine gtk2-engines-pixbuf
cd /usr/share/themes/ && rm -rf Arc*
git clone https://github.com/sagarpanchal/arc-theme-ubuntu.git
cp -r arc-theme-ubuntu/Arc* . && rm -rf arc-theme-ubuntu && exit
gsettings set org.gnome.desktop.interface gtk-theme 'Arc-Darker'