You can now choose the dark side in DevTools from Chrome 48. If you didn't knew anything about this feature, here you'll learn how to enable the dark theme to protect our fabulous eyes in the nights (or only to make everything looks cooler).
How to enable Dark theme
To enable the dark theme press F12 (inspect element or go to settings > more settings > developer tools). Once the developers tools are shown, go to the top corner of the menu (on the expand button) and choose settings (or press F1 directly if the developers tools is visible).
Then choose the Theme option in the Appearance area.
Finally, enjoy while you code in the night !
The feature still in beta as a lot of it is auto-generated, so if you see any possible improvement, let it know as a chrome bug ticket here.