You want to do this, because the UI needs a local CSS file to enable icon-search.

1. Go to the CDN and find the CSS you need - ideally a minimized format (faster). Download this file and put it into your app, probably under /assets/fonts/some-file-name.min.css
2. Modify all relative paths to the font-files to have the full CDN path
   1. Open the file in a text editor and look for the path to the font files (usually ending in .eot, .woff, etc.).
   2. Modify all these (usually starting with ../ or ./) to contain the full cdn path
   3. Test the path: copy the path you created with the font-file and paste it into a browser, to verify that a real font file is downloaded.