Inconistent website style headings

When implementing the new website style, I've noticed that many of the
header styles (h1, h2, etc...) are used inconsistently. This makes for a
messy looking website.

This is a big task to change all over the place by myself, so I need
your help.

So whenever you change a page in the documentation next time, please
make sure that the first header is "h1", and everything that is a
sublevel from there is "h2" up to "h4". Also, ideally we only want a
single "h1" per page and it should be at the very top.

Thanks!