Move CSS out of index and into it's own file
Switch from vw to em for font sizing

This was causing problems on screens, and for variable numbers of repos (eg, 4 was ideal, more caused problems)
Refresh the whole page once every 3 hours

As this usually runs on radiator screens it's easier if updates happen automatically,
without having to go find a keyboard and mouse. This will refresh the same URL and
load any changes.

Frequent enough to get changes, not so frequent it visibly refreshes to often