This theme now requires LaunchBox 12.7 or above to function.
A LaunchBox Custom Theme I developed to help me understand the code behind themes. Because of this, most items within the XAML files are commented, which were added in order to help me keep track of what was going on. Sources of inspiration include the Lambda theme and GOG Galaxy.
The notable item this theme accomplishes is the tab approach to the Game Details Page.
Please feel free to use parts of this theme in your own creations.
Extract the Neptune folder into LaunchBox\LBThemes
In LaunchBox, open Options, under Visuals > Main Window Theme and select Neptune from the dropdown.