Eclipse Remote Application Platform (RAP) - Deploy Custom Theme - eclipse

Question

Currently trying to get my Eclipse RAP application to work with a custom styling. The documentation is giving me one headache after another and it's really hard getting into it.
Following their docs and trying to extend the default theme, I have set up my plugin.xml as follows:
<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>
<extension
point="org.eclipse.rap.ui.entrypoint">
<entrypoint
applicationId="org.______.rap.branding.application"
id="org.______.rap.branding.entrypoint"
brandingId="______"
path="/rap">
</entrypoint>
</extension>
<extension
id="org.______.rap.branding.application"
point="org.eclipse.core.runtime.applications">
<application
cardinality="singleton-global"
thread="main"
visible="true">
<run
class="org.______.rap.branding.Application">
</run>
</application>
</extension>
<extension
point="org.eclipse.ui.perspectives">
<perspective
class="org.______.rap.branding.Perspective"
id="org.______.rap.branding.perspective"
name="name">
</perspective>
</extension>
<extension
point="org.eclipse.rap.ui.branding">
<branding
id="______"
themeId="org.eclipse.rap.rwt.theme"
title="______ Theme">
</branding>
</extension>
<extension
point="org.eclipse.rap.ui.themes">
<themeContribution
file="theme/______.css"
themeId="org.eclipse.rap.rwt.theme" />
</extension>
</plugin>
I've blanked out some parts, just asume they're all the same keyword, lowercase letters only.
My .css-File is as simple as it could be to see, if the hook works:
* {
background: red !Important;
}
But it just loads the default theme, no changes whatsoever and I can't detect the injection anywhere on the page.

Answer 1

Appears the hook itself is correct, but RAP couldn't handle the background-property. Changing it to background-color instead did the trick.