OSes: Xubuntu 16.04 host, Kali Linux guest in VirtualBox with seamless mode.
Desktop environments: XFCE4, XFCE4
Matrix background: Fullscreen Tilda terminal running cmatrix.
Dedsec background: orig07.deviantart.net/b633/f/2... but we cropped it.
Theme is a customized "Adwaita-dark" with the title bars black instead of blue and the text replaced with green (either #119900 or #55BB00 for the most part)