I was having some serious eye strain too.
Just add the following css between head tags:
File1: apps/{version}/html/toolbox/index.html
Add css between head tags:
<style>
.container-fluid{ background:gray;}
.panelgridtitle{ color:white;font-weight:bold;}
.panelgridtitleinner{color:white; font-weight:bold;}
</style>
File2: apps/{version}/html/scenario/index.html
Add css between head tags:
<style>
.titlebody{background:#fff;}
html{background:gray;}
.container-fluid.main{background:gray; }
</style>
And you should get a panel looking like this:
123.png