#credits { 
  display: inline;
  font-size: x-small;
 }
#header { 
  left: 3px; 
  top: 3px; 
  background-color: black; 
  width: 75%; 
  color: white; 
  z-index: 1;
  padding: 2px;
  font-size: larger;
}
#div1 { 
  width: 50%;
  background-color: green;
  color: yellow;
  display: inline;
 }
#div2 {
  position: absolute;
  left: -1000px;
  top: -100px;
  background-color: lightyellow;
  padding: 1em;
  border: 1px solid green;
}
#file1 { 
  background-color: lightyellow;
  border: 1px solid purple;
 }