body {
  padding: 0px;
  margin: 0px;
}

form, table {
  margin: 0px;
  padding: 0px;
  border: none;
}

img {
  border: 0px;
}

#game_box {
  position: relative;
  width: 600px;
  height: 400px;
  margin: 30px auto 30px;
  border: 1px solid #000;
}

#overlay {
  position: absolute;
  top: 0px;
  left: 0px;
  width: 600px;
  height: 400px;
}

.hidden {
  display: none;
}