I'm trying to update a cottage website by replacing an obsolete calendar (to show booking dates) with one that works. For the now-obsolete calendar, I used an iframe linked to a calendar on another website, which displayed in the right position on the page. Now I have changed the iframe link to use an embeddable Google calendar, which draws its data from an ical link from an Airbnb calendar. Although the iframe now displays the calendar I want, the frame is no longer properly aligned, so the calendar is unreadable (see attached images).
I'm  baffled. Could anyone suggest why this problem arises, and how I can fix or work around it?