title: How to reduce the full screen mode in emacs
body: <p>I have a little problem when I'm in the full screen mode in emacs , how can 
  return to the default mode , for more explanation this is my problem .</p>
  
  <p>I open a file in full-screen mode with emacs -fs filename.txt, after i want to  reduce it to default or normal mode (size) . and thanks a lot for your help and your time I really appreciated </p>