[events] shortcode doesn’t display the date range search box correctly

Hello,

This plugin seems to do exactly what we need; list all events with a date range search filter on top of the list. Everything looks nice except the date selection box has shrunk into a small box that doesn’t invite anyone to click on it.

To demonstrate, here is a link to two screenshots:
Screenshot 1: The date range selection box unclicked
Screenshot 2: the date range selection box clicked

Help is highly appreciated.