Same here, even when I use correct (I guess) code. I am having a header hight 110px. Then inside a page, I add a section and for that section’s “Hight” I use the: calc(100vh - 110px) --but it doesn’t work. Still just 100vh, no minus 110px… Anybody more familiar with this can help? Thanks!
I just checked your link, but it is not showing a fixed height of 110px in your header (in the height meta box inside the header template). Also, it is not showing the calc in the section on the page. Have you removed it?
Edit - I can see the fixed height on the header - nested on 2 divs down
Ps. I would also put the calc in max-height instead of height.