I recently switch to Chrome from Firefox. I’m not sure how long I’ll stay but I really missed Firefox’s awesome dark Developer Edition Theme. The Chrome web store was lacking an equivalent, so I made one! You can find it on the Chrome Web Store under the name, Developer Edition Dark. It’s open source on GitHub too!
In the rest of this post, I’ll provide some notes on Chrome theme creation. Documentation online was quite sparse, so if this helps someone else I’ll be happy.
Chrome Theme Documentation
You’ll want to start by reading Chrome’s theme documentation. It’s pretty sparse, but it provides a good template for building your own theme. When I was creating my theme, I was surprised to learn there is no way to specify a flat color to use for certain parts of the UI, such as the tabs, tab frame, and toolbar! If you’re spending a lot of time Googling that, it’s time to give up. You’ll have to use an image.
Next, look over this Google Chrome Theme Tutorial, which goes into more detail about what bits of JSON do what in the Chrome UI. You can use the tool linked on that page to create a basic theme and tweak from there. I’d even encourage you to look at my theme’s source if it helps at all. I didn’t mess with any of the new tab page stuff, so my theme should serve as a simple example to learn from.