How to install:
- Open your Chrome settings page
- Click on the extensions tab
- Enable developer mode
- Download the .zip file from this repository
- Extract the contents of the zip to your preferred location
- Drag and drop the extracted folder to your Chrome extensions page
- Enable the extension if it's not enabled yet
Or download the stable version from the chrome webstore Here
More themes
Feel free to create your own stylesheets/themes for gitter, toss them in a pull request and I'll check them and push them out on a next update.