Mermaid graphs size

[AntowaKartowa]

Hi. First of all thank you for super cool notebook and that you add support for mermaid charts. But one thing doesn't let me use their full power.

If I generate small simple graphs they look OK or even too big (letters, squares). But if I need more nodes and leafs its veiwport stay fixed, but font-size and squares start decreasing and at some point it is unable to read text in the blocks. From the user perspective It would be better to have fixed font size and resize automatically viewport to fit the graph content.