Hello @pcwitcher,

To make the background black every where use below given CSS.

#main {
    background: none repeat scroll 0 0 #000000;
}

#panel-11-0-0-0> .panel-widget-style {
    background-color: #000 !important;
}

#pg-11-0> .panel-row-style {
    background-color: #000 !important;

Hope this helps .

Best Regards!!

Have a good day .

Hello @pcwitcher,

Glad we could help you .

If you have any issue further then please let us know .

Best Regards!!