You can customize the look of the UI to match your branding.
The customizations are stored in a JSON text stored in the installation content.
You can edit this field directly in the new edit UI via the "System" main menu item.
We will add a more userfriendly UI soon, but for now you can simply edit the JSON file to customize the look.
Here are some examples: 
configs.zip
This applies to builds after b2015.