Too Much Width & Height

[ricardoaguilarm]

I’m creating a simple tip calculator, based in a dribbled design.
I’m following mobile first aproach, exactly iphone 6/7/8 (375 x 667).
BUT i’m having a lot of extra space in the design, and i don’t know what is happend.

Can you rate my code and teel me what i’m failure? Thanks in advance!

CODEPEN:
https://codepen.io/ricardonothing/pen/QWywEMj

Captures:
Looks normal, but when you move the mouse… in the second capture we can see the extra space.

[nhcarrigan]

This is what I see. No extra space around the sides, but the text at the top overflows.

[ricardoaguilarm]

I dont’t understand anything CSS is hard.