Using built-in browser fonts

This example shows what happens when auto-loading of fonts from Google is turned off and no other fonts are configured:

regular - bold - italic - bold italic - code

You can inspect which fonts are actually used by your browser by using the built-in web developer tools (available at least in Chrome, Firefox, Safari, Edge) and choosing the fonts view. Try this with multiple browsers and compare the results to see if using only built-in fonts is an option for you.

How it works

Turn off the default use of Roboto fonts loaded from Google Fonts in your mkdocs.ym:

theme:
  font: false

The fonts used are those that are built into the web browser. Material for MkDocs provides sensible defaults that should work in all common browsers.

(Dis-)Advantages

Turning off Google Fonts means that your website will not cause browsers to make any font requests to Google, improving privacy. It also improves performance and network traffic, though browser caching means the advantages over fonts hosted on CDNs is small.

The downside is that you lose some control over the visual appearance of your website as different browsers will choose different fonts.

Alternatives

Privacy Plugin

The privacy plugin provided by Material for MkDocs provides a best-of-both-worlds solution in that it allows you to specify fonts available on Google Fonts directly in your mkdocs.yml. It automatically downloads the ones used and includes them in your website so they are served up by your own server. No need for a custom stylesheet.

An alternative is to turn off the use of Roboto from Google Fonts and then configure custom fonts to use, as shown in this example that shows how to switch to the Noto font family.