Seems to work in postbit legacy only then.
That's a bit stupid.
I guess you could just add it to the postbit template in some way.
Checked it - the stylevar itself definitely works, it just isn't present within the
postbit template, only
postbit_legacy.
So it can just be added as a background to the relevant template code. Something like
Code:
style="background: {vb:stylevar postbit_background};"
That will definitely work. As will postbit_userinfo_background, which is usually slightly darker (a bit like alt1 and alt2 on vB3).