How to prevent div's from exceeding certain widths when using css percentages?

How to prevent div's from exceeding certain widths when using css percentages?

I am trying to design a site using Jquery Mobile Framework that I want to be able to be viewed also on a regular pc and look fine. my problem currently is that everything stretches out to the necessary widths I set for mobile screens and looks terrible on a normal PC screen. Is there a way I can set things to NOT exceed a determined width on larger screens? Thanks!

here is my css im currently using for the logo resize:

  2. #logo-center {
  3.     width: 100%;
  4.     text-align: center;
  5.     margin-right: 0;
  6.     margin-left: 0;
  7. }

  9. #logo-center img {
  10.     width: 80%;
  11. }