style.css

html {
    position: relative;
    height: 100%;
    padding: 0;
    margin: 0;
    padding-top:0px;
    background: url("background.jpg");
    background-size: cover;
    color: white;
}

* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    position:relative;
    height:100%;
    padding: 0;
    margin: 0;
    width: 100%;
}

.block {
  display:table;
  width: 50%;
  position: absolute;
  height: 100%;
}

.block-cell {
  display: table-cell;
  vertical-align: middle;
}

.app-icon {
  height: 50%;
  width: 50%;
  background: url("appicon-clear.png");
  margin-right: auto;
  margin-left: auto;
  background-size: cover;
  background-position: center;
}

.title {
  margin-top: 10px;
  text-align: center;
  font-size: 40px;
}

.iphone {
  height:600px;
  width:auto;
  background: url("iphone.png");
  margin-right: auto;
  margin-left: auto;
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;

}