Use the sliders or number inputs to adjust the colour transformation matrix. The input red/green/blue are the default HUD colours and the output red/green/blue are what is shown. For example, putting 100% of input red to input blue (and nowhere else) makes everything that is red by default show as blue.

Copypaste the generated configuration snippet on the left into the file GraphicsConfiguration.xml , replacing (only) the similar lines inside the <GUIColour><Default> tags. Note that this file is overwritten when the game updates, so you will need to re-apply your theme every time that happens. The file GraphicsConfigurationOverride.xml can be used to make the theme persistent (see example).

Refer to the forum thread for help and feedback regarding the theme editor.

You can link to themes directly in the editor by copying the URL from “link to this theme” below.

This completely unofficial and unsupported editor was made by Kimmo Kulovesi (aka Arkku). Provided as is with absolutely no warranty, mod the game at your own risk only!

The screenshots are obviously from Elite: Dangerous by Frontier Developments plc, with which the author is not affiliated other than having backed the game. =)