How to center an adaptive block?

Question

css

Good day. What is the best way to center a block in the middle (vertically and horizontally) of any screen resolution, while maintaining the block's height/width proportions?

Answer 1

Wrapper above the block:

{
display: flex;
justify-content: center;
align-items: center;
}

Answer 2

{
position: absolute;
margin: auto;
width: 90%;
height: 90%;
top: 0;
right: 0;
bottom: 0;
left: 0;
}