html,
body {
  position: relative;
  width: 100%;
  height: 100%;
}
.startpage {
  width: 100%;
  height: 100%;
  background: url(../images/index.jpg) no-repeat center top;
  background-size: contain;
  cursor: pointer;
}
.startpage footer {
  position: absolute;
  bottom: 10px;
  width: 100%;
  color: #000;
  font-size: 14px;
  text-align: center;
}