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

You need to have a container for your content div that you wish to be 100% - 100px

#container {
   width: 100%
}
#content {
   margin-right:100px;
   width:100%;
}


  

      Your content here
  

You might need to add a clearing div just before the last