Looking to squeeze the space around a logo

This is in screen.css, and actually I would suggest creating a child theme instead of modifying the theme files so that whatever changes you make to the CSS do not get overwritten by a theme update.

If you are uncomfortable with setting up a child theme, you could install the WordPress.com custom CSS plugin which will store your CSS changes in your database, keeping them safe from theme updates.

You can then add this and play with the first and last values (first is top, last is bottom) in the margin declaration. The original top and bottom margins were 60px.

#header {
margin: 30px 0 10px;
}