How do I change the look of my spoilers?
Most likely the spoilers are styled inline, so you can change their look by editing the MyCode.
How would I do that and what do I edit them to?
You go to Admin CP > Configuration > MyCodes. Select the spoiler MyCode and edit the replacement code to whatever you want it to look like. You need to know a little HTML and CSS.
Afraid I'm not that experienced in those areas. Is there any pre-made looks I can get?