How to create a custom theme in Sublime Text 3.
- Select Sublime Text / Preferences / Browse Packages …
- Create a folder adjacent to the Users folder called THEMES.
- Any any custom themes you want to your new THEMES folder, for example 1337, or create your own file to that folder
- Back in Sublime Text 3, select Sublime Text / Color Schemes / THEMES / YourTheme.tmTheme to use it.