I've noticed you're trying to do this purple and orange thing with the whole theme, and I like that layout, it's similar to one of the 3DS themes I made based off of Sonic CD's Palmtree Panic bad future.
I might go ahead and do a recolor for the icons and the logos making them Orange/Purple and see which one looks better.
Anyway, I went ahead and found a fix for one of the complaints I made earlier involving the background image not meshing well.
body{
background-image: url("https://wallpaperscraft.com/image/space_art_universe_97750_3840x2160.jpg") !important;
background-repeat: no-repeat !important; /* Stops the background from repeating */
background-attachment: fixed; /* Creates a parralax effect so that way to background never moves, even if you scroll the page. */
padding-top:16px !important;
margin:0 auto !important;
}
Enjoy.