Clickable Masthead

Hi. After heavily modifying the Benevolence 1.0 theme for my site, I would like to make my masthead/header image clickable so that the visitor can return to the main page once clicked. For the life of me though, I can’t figure out the line of code I need to do it. I know everything is condensed into my header.php file, and I’ve read all of the previous posts about this, but I just cannot figure it out on this theme. Any help would be greatly appreciated.

Here’s my site code:
https://wordpress.pastebin.ca/253017

Here’s my site with the masthead I want to make clickable:
https://audictive.ofadam.com/