[SOLVED] Link Category Affecting CSS

Each of the three boxes on my page should have a 1px border. As you can see, only the center box is showing the border:

http://www.neshamahyoga.com/v2/off-the-mat/

Each box is a widget. When each widget points to the "living your yoga" category, borders appear around each box. When I added the "connections" and "masters" categories, the borders disappeared. I am completely stumped as to why this happened. I did not add any plugins. I did not change the CSS. I did not do anything except create the two new categories and point the widgets to them.

Could this be a bug? Any help greatly appreciated!