p {
  margin-top: 2em;
}
  
h2#first {
  margin-top: 1em;
}
  
h2 {
  margin-top: 1.5em;
  margin-bottom: -0.5em;
}

pre {
  margin-bottom: -1em;
}

#firefox {
  text-align: center;
}
/*
#firefox
{
  width: 180px;
  height: 60px;
  position: absolute;
  left: 750px;
  margin-top: 2em;
}
*/