Julian,
Glad you fixed the Sandbox issue. That can be annoying, and unfortunately, isn't a setting we can control with our Autotune tool.. we wish we could disable it automatically.
As for the graphical issues, I just tested in Chrome and Firefox. I saw a black background on both, and all that was different was that the remember me check box was centered in Firefox. In both, the "Register" button was white-on-white, making it hard to read. I didn't see a yellow background on either.
Boiling it down, there's basically some conflicts between our SCLogin module and your template's CSS files. All should be pretty easy to fix. For instance, in /templates/prestige_academy/css/template.css around line 867, you'll see:
#cboxLoadedContent a, #s5box_register_inner {
color: #FFFFFF !important;
}That's what's making your register button text white instead of black. If you remove that statement, it should fix our login module, but of course you'd need to test that it doesn't cause other problems.
Likewise, in the same file at line 800, you'll see:
#cboxLoadedContent input {
width: 80%;
}That's causing the checkbox to be too big and causing the text to wrap like you see.
Try altering those values and see if that makes things better for you. If not, or you have specific things you'd like to correct, let us know and we'll help you with those as well.
Thanks,
Alex