@betro-hakala I don't even know what you want to be transparent. Also, if you are using Vanilla theme (not Persona) then the theme's options won't be in NodeBB Category options, those are completely different.
Could you send a screenshot of what you want transparent? That would help us help you.
"Do you really need jQuery?"
I actually read about that site before the blog post, and later that day also saw this: You will probably need jQuery
Assuming you're talking about my blog post from this morning?
@julian yep, talking about that one. I've actually done some testing with a web app I developed on the performance between jQuery and vanilla JS. It's only sometimes that vanilla is really faster. (I did manage to get one jQuery routine from about 300ms to ~14ms with vanilla JS though!)