The icons are broken in firefox because you used a webfont wich is hosted on another domain. Edit: Just saw that you already know about this: https://github.co

The icons are broken in firefox because you used a webfont wich is hosted on another domain. Edit: Just saw that you already know about this: https://github.com/google/WebFundamentals/issues/13 https://github.com/google/WebFundamentals/issues/13 --- Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://web-central.appspot.com/web/essentials/icons/icons.woff https://web-central.appspot.com/web/essentials/icons/icons.w.... This can be fixed by moving the resource to the same domain or enabling CORS.