Thanks to both of you!
If you want to totally change the look of a spoiler button, you have to add/edit (depending on if your theme has it or not) it into ipb_styles like this:
.ipsButton_secondary,
.bbc_spoiler_show,
.user_controls li a{
After .user_controls li a{, you put all your customization options; though, I just moved those over from a different theme.
The margin-left: 20px fixed the issue with it overlapping as well. Thanks, Phun.