Original Gtk theme: Euqilux Theme
Just clone this repository and copy json file from it to /usr/share/bumblebee-status/themes/
directory:
git clone https://github.com/Smarthard/bumblebee-status-theme-equilux
sudo cp bumblebee-status-theme-equilux/equilux.json /usr/share/bumblebee-status/themes/