Nebula is a round, consistent, optimized, full dark blue theme.
For this Powercord theme you need the Discord Canary Version and a Powercord Installation.
For good theme management use the Theme Toggler plugin.
To install the Download and Install the Theme use this command:
cd powercord/src/Powercord/themes && git clone https://github.com/Pavui/Nebula
To update the theme use this command:
cd powercord/src/Powercord/themes && git pull