* {
  padding: 0;
  margin: 0;
}
.container {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translateX(-50%) translateY(-50%);
  width: 600px;
  height: 400px;
  overflow: hidden;
}
.container .img {
  position: relative;
  width: 4200px;
  height: 400px;
  font-size: 0;
}
.container .img img {
  width: 600px;
  height: 400px;
}
.container .bottompoint {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
}
.container .bottompoint div {
  float: left;
  background-color: #aaa;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 1px solid red;
  margin: 0 2px;
  cursor: pointer;
}
.container .bottompoint div:hover {
  background-color: #acf;
}
.container .bottompoint .on {
  background-color: #acf;
}
.container a {
  position: absolute;
  top: 0;
  bottom: 0;
  margin: auto;
  display: inline-block;
  width: 20px;
  height: 20px;
  background-color: #black;
  opacity: 0.7;
  text-decoration: none;
  color: white;
  font-size: 48px;
  text-align: center;
  line-height: 20px;
}
.container a.prevpoint {
  left: 10px;
}
.container a.nextpoint {
  right: 20px;
}
