use separate colors for the background, gutter, and folder tree

the gutter's background color can be changed by changing the overall background color of the theme, and then adding a rule for the "text" and "source" scopes in the theme's configuration file (.tmTheme file), effectively overriding the default background color and obtaining a different gutter background color, like this:

<key>background</key>
<string>#1e1e1e</string>

And then, add the following:

<dict>
  <key>name</key>
  <string>Source base background</string>
  <key>scope</key>
  <string>text, source</string>
  <key>settings</key>
  <dict>
  <key>background</key>
  <string>#222</string>
  </dict>
</dict>

Wow, uh.. okay. That works! Not really sure why that's not part of any of the standard themes, but.

For those still reading this, you can simply change gutter background.

Open your theme configuration file (.tmTheme) and add :

        <key>gutter</key>

        <string>#E3E3E3</string>

You can also change gutter foreground :

        <key>gutterForeground</key>

        <string>#E3E3E3</string>

Wow. I'm glad that this exists, but uh... where the hell is this documented? Is it even?

Not documented... Found this on some lost forum thread from years ago !