How do I set the width and height of a section to be 100% in size of the computer's screen, using css

Answer 1

100vw, 100vh.
% is used to match the size of the parent while view-width and view-height matches the viewport.

Answer 2

You can use
.section{
position:absolute;
width:100%;
height:100%;
}

Answer 3

section {
width: 100%;
height: 100%;
}