Largely based on the Flat Dark theme, with updated colors and shading to better match the Twitch dashboard.
Download and extract contents to C:\Program Files\obs-studio\data\obs-studio\themes or wherever your OBS install resides.
Restart OBS and select the Material Dark theme from Settings >...
A Flat Dark Theme for OBS Studio.
How to install
1. Drag the zip file into your OBS Studio Theme Folder (...\obs-studio\data\obs-studio\themes).
2. Unpack files into the Themes folder.
For latest changes download from Github