No Events Page customization and height

Hi guys,
I need to customize event page:
if there’s no event I would like to show some links/image and not only a text.
1) How can I do?

2) If there’s no event, body page is has not full height: see here https://www.dayroma.it/wp-content/uploads/2016/10/screen.png

How can I have a full height body if there’s no event?

Thank you