#slider {
  position: relative;
  overflow: hidden;
  margin: 0 auto;
  border-radius: 4px;
}

#slider ul {
  position: relative;
  margin: 0;
  padding: 0;
  height: 200px;
  list-style: none;
}

#slider ul li {
  position: relative;
  display: block;
  float: left;
  margin: 0;
  padding: 0;
  width: 780px;
  height: 480px;
  text-align: center;
  background: no-repeat;
  background-size: 780px auto;
}