Ahh, thanks for the clarification and re-enabling the module. I can see we're doing something different for that button, which is a bit confusing. The styles to target the button you mention are below:
The 'normal' color when not hovered over:
.sourcecoast a.btn-primary {
color: black !important;
background: red !important;
}
The styles when the mouse is over the button:
.sourcecoast a.btn-primary:hover {
background: yellow !important;
text: black !important;
}
I'm not sure if !important is actually needed after each one, but it guarantees those styles will be used.
The next release of the SCLogin module will have broken out CSS files for the different styles and should be much easier to modify. That release is planned for mid/late February.
Best of luck to you,
Alex