div.center {
  position: absolute;
  top: 50%;
  left: 50%;
  margin-top: -270px;
  margin-left: -450px;
  padding: 0;
  width: 900px;
  height: 540px;
  background-image: url(../image/vk.png);
  background-repeat: no-repeat;
}

body {
  background-color: #c0c0c0;
  color: #c0c0c0;
}