How to calculate the width of a div?

Question

css

I make the central block (red) a fixed width of 1024px and center align margin:0 auto;
But how do I add the outer blocks so that they stretch indefinitely, but at the same time the central one is always positioned in the center?

Answer 1

I would put three blocks - left, middle and right. Give them float: left; Middle width: 1024px; Left and right - width: calc(50% - 512px);
PS Example here: jsfiddle.net/Ivanq/hL38md04/1