added some link, nav tab and button stylings for NYU SH umlaut

A little customization to get us started. The rounded corners are used throughout so I left them alone, but I added a gradient on tabs and tweaked the colors to use NYU's purple and NYU Shanghai's red/pink in some places.

The Dummy app doesn't have any search result pages, so this can get us started and I guess I can tweak further once these styles are in the wild.