body {
  background: #330033;
  color: #999999;
}

div.upper_left {
  background: #ff0000;
  position: absolute;
  left: 0;
  top: 0;
  width: 400;
  height: 300;
}

div.upper_right {
  background: #00ff00;
  position: absolute;
  left: 400;
  top: 0;
  width: 400;
  height: 300;
}

div.lower_left {
  background: #0000ff;
  position: absolute;
  left: 0;
  top: 300;
  width: 400;
  height: 300;
}

div.lower_right {
  background: #ffff00;
  position: absolute;
  left: 400;
  top: 300;
  width: 400;
  height: 300;
}