How to align a box in center

Question

Make a code in solution on this

Answer 1

https://sololearn.com/compiler-playground/WYIbdBo85KsT/?ref=app

Answer 2

you could use a flexbox
https://www.w3schools.com/csS/css3_flexbox.asp
https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout/Basic_Concepts_of_Flexbox