Embed block is to small. How can I customize it?

Hello Squarspace Forum.

On my new website, I have a small issue, hopefully.

I implemented my service menu (offered by a german provider) into my website. 
Its on the page "book an appointment"
https://www.veitgross.de/termin-buchen

I used embed block and this code to do it. But as you can see, the service menu is not shown in total and you have to scroll now.
Do someone of you guys know how I could fix this?

I would really appreciate your help.

Thank you

Veit

Have you solved yet?