Here’s the code:
<style>
<tr><td>
<p>Section Title Here</p>
</td><td>
<p>Whatever you want here</p>
</td></tr>
</style>
Bolded portions can be changed to whatever you like (I put the <p> tag as bolded since you don’t necessarily need them if you’re not writing a paragraph in the section. For example, I use bullets in my new sections so I don’t use the <p> tag, if that makes sense). For example, here’s the code for if you wanna make a section focused only on games:
<style>
<tr><td>
<p>Video Games</p>
</td><td>
<p>I love playing Minecraft and Pokemon!</p>
</td></tr>
</style>
You can put this code in any of the sections and it’ll work, but where the new section ends up depends on where you put the code. If you put the code in the General section, the new section will be under General. If you put it in Heroes, it’ll be under Heroes.
There's code to change the Interest sections themselves but it has never worked for me. While I'm able to see the change when I'm logged in, apparently other users cannot so... But see if it works for you!