How can I do width = 100% - 100px in CSS?

Question

In CSS, how can I do something like this:

width: 100% - 100px;

I guess this is fairly simple but it is a bit hard to find examples showing

Answer 1

Working with bootstrap panels, I was seeking how to place "delete" link in header panel, which would not be obscured by long neighbour element. And here is the solution:

html:

    Long link header Long link header
    Delete

css:

.with-right-link { position: relative; width: 275px; }
a.left-link { display: inline-block; margin-right: 100px; }
a.right-link { position: absolute; top: 0; right: 0; }

Of course you can modify "top" and "right" values, according to your indentations. Source