Reduce height of page title

I want to reduce the height of the page title. Currently there is a lot of white space that I don’t want.

I looked at multiple threads (on here and other sites), and all of them suggested adding custom CSS code. Things like:
#masthead .site-logo {
max-height: 80px;
}

#masthead {
padding: 5px;
background-color: rgba(255,255,255,0.7);
}

I pasted these in custom CSS, and adjusted the values, but none of them worked for me.

First time posting, so I’m very open to comments on best practice etiquette on here (did read the guidelines, but may have missed something)

The page I need help with: [log in to see the link]