They are themes of 16 colors carefully designed by Ethan Schoonover to reduce eyestrain plus maximize readability at day and night.
I was shocked to find nobody on the forum has adapted Solarized for the PB IDE. So I took a shot at it, but I am open to feedback and improvements.
Solarized for PureBasic IDE on GitHub
Direct: Solarized-Light.prefs , Solarized-Dark.prefs
You can import these color prefs files through the IDE's Preferences > Import/Export screen, or try my IDE tool for "instantly" switching color themes: ChangeTheme

Solarized webpage (by Ethan Schoonover)