How do I edit the Solarized (Light) theme in Sublime Text 3

I have managed to find a solution:

Go to http://tmtheme-editor.herokuapp.com (someone has built a web-based theme editor). Once you have tweaked the colour syntax you can download the themename.tmTheme file. Move that file to /Users/username/Library/Application Support/Sublime Text 3/Packages/ User/ (if you are on a Mac).

Load in the syntax theme from the top menu: Sublime Text > Preferences > Color Scheme > themename.

If you want to tweak you syntax further up can upload the custom theme back in the web-based theme editor and save it out again.

Hope this helps someone else.

Editing is way simpler than advices above.

1. Go to Sublime installation folder, find there Packages subfolder.
2. Open Color Scheme - Default.sublime-package as a zip archive (I use Total Commander and Ctrl+PgDn keys).
3. Find there any scheme you like *.tmTheme, copy to HDD and edit with any XML editor.
4. Pack modified file back (with Total Commander just copy file to opened archive).

I'd recommend using PackageResourceViewer to open the file. You could make your modifications there, and it would save in the proper location to override the built in files. However, I would recommend copying the contents of the file and creating a custom version in your User folder. That way, you can easily move it around and modify it without worrying about the built in color schemes.

The default color scheme files are located in Color Schemes - Default.sublime-package. In ST2, this was extracted to Packages/Color Scheme - Default. PackageResourceViewer will display these folders (as they would normally appear in the Packages folder in ST2. You could navigate to your color scheme from that.