HTML heading sizes

[evildmp]

Hello @hawkz, could we have some heading size/spacing re-adjustments please?

• h3 is a bit large
• h4 is too small, and its margin-bottom is excessive I think

http://2016.pyconuk.org/accommodation/ shows headings down to h4.

Thanks!

[inglesp]

@evildmp Is this still a problem? I spotted a commit that tweaked header sizes a few days ago.