Help. center my calculator

How can i center this calculator?
CODEPEN: https://codepen.io/ricardonothing/pen/ExagXWR?editors=1100

My approach would to be making your .main

a) display: flex
b) direction column
c) alignment center
d) justify center
e) height* 100 view height

Thanks a lot! i was a little confused because are two display: grid & flex.

You can do the same with only grid!

width:100%;;
	height:100%;
	display:grid;
	grid-template-columns: 10% 1fr 10%;
        grid-template-areas " . main ."

main { grid-area:main;}

hope it helps! good Luck!