Use system font stack in docs?

[grobinson-grafana]

I wanted to see if there was any interest in using the system font stacks in prometheus.io docs?

Standard text would use the font stack:

font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, Cantarell, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";

and monospace text would use the font stack:

font-family: ui-monospace, "SF Mono", Menlo, Consolas, Monaco, "Ubuntu Mono", "Source Code Pro", "Liberation Mono", "Lucida Console", monospace;

This covers most platforms including Mac OSX, iOS, Windows, Android, Ubuntu Linux, most Linux distributions using GNOME desktop.

[grobinson-grafana]

@juliusv do you have any opinions on this, as author of #386?