Using HTML Headings With HTML5
When using HTML5 elements, h1 to h6 headings are mostly redundant since the elements themselves contain the headings that are related to the content.
Of course, its still necessary to use an h1 heading for the website name in the header and an h2 heading for the page name.
As can be seen from the screenshot of the widget settings to the right, headings can be inserted correctly using the chosen font, a web safe fallback font and the generic group.
Using a web safe fallback font and a generic group is essential if a non web safe font - and even a Google hosted font - are used.
Web safe fonts are those that are available on every computer - not just Macs - so, if a chosen font fails to download, the browser will substitute the fallback font rather than the browser default.
A fallback font should be chosen so that the web page layout is not compromised when it is substituted. Get more information about choosing and using fonts and info about fallbacks and generic groups.