You could add the below CSS to get your forums off your header and make the forums fill the page width.
You’d want to add the code to style.css
file, preferably in a child theme so that when you update you don’t have to re-add the code. Or if that theme has a options panel with a area to add custom CSS.
body.bbpress .content-wrapper .content-area {
max-width: none;
padding: 0 7px;
}
body.bbpress .content-wrapper,
body.bbpress.no-sidebar.page .content-wrapper {
margin: 0;
padding: 0;
}
body.bbpress .site-content {
padding: 30px 0;
}
Just thought I’d throw that out there as a option 🙂