Fix the problem with Google Fonts

[augusto-herrmann]

As the site migrated to modern Node.js (#111), the fonts are broken in the page's text.

It seems like the Google Fonts are being blocked for using mixed content:

Happens in Firefox 92.0 (64-bit) and also Chromium 90.0.4430.212.

We need either to solve the problem so that the fonts load or to replace the fonts by loading from somewhere else.