Why is alert dialog transparent?

[mambucodev]

It's got the bg-background class which means the background will be colored with --background. I also checked and --background is defined and is actually a color. but still, the alert dialog is transparent. By putting bg-black it colors, but I want it to follow my theme so I need it to not be transparent.

[mambucodev]

P.S. I don't care about the URLs in the background or whatsoever, so don't tell me "Oh you've got URLs leaked in your photo!"