How to enlarge Sketchfab UI in embedded iframe on mobile only?

I’m not a dev, just know enough code to reasonably do a few things. I don’t know if this is a Sketchfab question, or if someone more knowledgeable with CSS can help.

I’ve embedded a model on this page with a little room for text below it:

When accessed on mobile, this CSS scales the text up, and scales down the iframe’s container height***:

@media only screen
and (min-device-width: 375px)
and (max-device-width: 812px) {
body,html {
font-size: 40px;
color: #fff000;
.container {
height: 80%;

However, if you check that out on a mobile device with a high res screen, Sketchfab’s UI is tiny. Screenshots attached.

How can I scale up the UI for mobile, as it looks on Sketchfab?

Too small:

Desired size:

OK on Desktop:

*** Actually, certain model effects or materials seem to have issues at ratios past a certain height, but that’s another topic.

Perhaps something in the Viewer API documentation will be of help? Viewer API - Introduction - Sketchfab