This theme is released as is without guarantee and without support. The HTML for the main menu is a total mess and a nightmare to work with. This theme is not completed and will remove some menus from your game such as "Find multiplayer game" and "Creations". You may modify and redistribute this theme as you please.
For proper font rendering, you must install the following fonts on your computer (Mona-Sans.ttf and all other variants found in the TTF subdirectory):
https://github.com/github/mona-sans/releases/tag/v1.0
This does not change the appearance of Source's menus, for that, see this project:
https://github.com/JWalkerMailly/Source-Github-Theme
For GMod's Derma components, see this project:
https://github.com/JWalkerMailly/Derma-Github-Theme
- Navigate to your garrysmod/garrysmod folder.
- Make a backup of html, resource and backgrounds folder.
- Drop the folders you backed up with the ones found in this repo and overwrite files with same name.
- Give a rest to your eyes.