Change the model to fit the mockup

The model for the mock frontpage is the same as used in the mockup, so
data is more realistic
Add Source Sans Pro Semibold

I'm now using this hosted typeface. It's the original Source Sans Pro
Semibold, but saved in an OpenType container and stripped of hinting
info (fonts with hinting look god-awful because of the butchered
letterforms, fuck hinting).
Style the post list

Before this, only the headlining posts were styled. Now it works for the
regular post list as well. Completely responsive, and it's cute.