HTML calendar shows up too small on page

I own a gym and I was able to post our calendar/schedule on our site. My problem is that when the site is published, the box the calendar is located in is too small, making it hard to navigate through. There are no settings to adjust the site and it doesn't matter how big I expand the box around it in the builder, it still shows up the same size when previewed or published.

Anyone know how to fix this?