Coming soon ping

I'm baffled by this one. I measured pixels on the photo and translated to rem. Absolutely no idea how h1 looks smaller when I measured 36px(2.25rem) wrote 2.5 by mistake and still looks too small by the look of it it should be closer to 3rem... the photo they provide is messed up or is there more to it just measuring pixels on ipiccy?

Same with input field, measured font 12 pixels and padding 20 px but just look at the difference...