Looks like your stylesheet refers to a font file that doesn't exist.
- In your project's theme folder, you probably have a lib.css file at ./styles/css/lib/.
- Open that and find the references to proximanova-*-webfont.woff. They likely use a relative path to point to a directory
- Your proxima nova font files should be in your theme folder, at the same relative path from lib.css
I'm guessing those files are either missing or not in the right location.