I've made a list of the buttons that currently work (it can change):

Input this into your Source Code:
<a href="LINK" class="CLASSIDHERE">YOURTEXTHERE</a>

The possible class id's that I've found are:
1) Btn2
2) css-1i9rl65
3) glow-logo css-ne3tzp
4) css-qsvin0
5) glow-on-hover pp-top-bar-create-char css-1yhasuw
6) css-17m14y8
7) css-1vh5zal
8) Btn2-purple pp-pg-total css-72h1ey
9) Btn2 css-hxluyi
10) characterInfoShinyBoxInner_1tqgq_107
11) react-select_control css-13cymwt-control

you can manually change the link and add a color the same way you would with any text except for some reason the color doesnt work too well for the yellowish brown button from what i've seen. I hope this helps!