Removing black line from around header image opacity change in primary section

Heya,

Just wondering how I would remove the black line from around the header image?

Also is there a way to make the main body/site… I think it is called “primary” be semi transparent?

I’ve tried

#site {
background-color: rgba(255, 255, 255, 0.8);
}

.body {
	background-color: rgba(255, 255, 255, 0.8);
}

#primary {
background-color: rgba(255, 255, 255, 0.8);
}

And different variations of them all but none of them seem to have any effect on it.

Cheers,
Gerald