body, html{
  margin: 0;
}
#rollover {
  position:relative;
  text-align: center;
  border: 0px solid #999;
  width: 300px;
  height: 600px;
  cursor: pointer;
  overflow: hidden;
  box-sizing: border-box;
}

button {
  background-color: red;
  color: #FFF;
  border: none;
  outline: none;
  font-size: 16px;
  padding: 10px;
  cursor: pointer;
  width: 120px;
  margin: 50% auto;
}