Optimize font loading

[devnook]

No description provided.

[devnook]

e.g. https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/webfont-optimization#optimizing_loading_and_rendering

[samdutton]

I've had a go at this on the font branch.

I followed suggestions from the article, but they seemed to make loading slightly slower.

Using what we had before, with a link to the Google Fonts CSS file (and no <link preload ...>) DomContentLoaded for the home page and other pages is 1.34 s according to Chrome DevTools in Fast 3G emulation.

Removing the link to the Google Fonts CSS file, and only adding the required @font-face rules to main.css, and adding <link preload ...> for each required font weight, DomContentLoaded is 1.52 s.

Please check the font branch — I may be doing something wrong :).

If not, I suggest we leave the usage of web fonts as it is.