CSS: Make a block element fill the entire space of a parent element?

Question

I am trying to put a link in a element and have the element fill the entire space of the . While I can

Answer 1

You need to give the a height, so that your style block will end up something like

th {
  font-size: 50%;
  width: 20em;
  height: 8ex;
  line-height: 100%;
}

Edit: Actually, for height you should probably use a vertical measure like "ex", instead of a horizontal measure of "em". Example changed to reflect that.