body {
  margin: 0;
  display: flex;
  justify-content: center;
  height: 100vh;
  align-items: center;
  text-align: center;
  font-family: Impact, Haettenschweiler, "Arial Narrow Bold", sans-serif;
  overflow: hidden;
}
h1 {
  font-size: 100px;
  color: aliceblue;
  backdrop-filter: brightness(0.5);
  letter-spacing: 4px;
}
.btn {
  background-color: black;
  color: white;
  padding: 20px 40px;
  font-size: 25px;
  border: 4px solid;
  cursor: pointer;
  transition: 1s background-color;
  white-space: nowrap;
}
.btn:hover {
  background-color: white;
  color: black;
}
.split {
  width: 50%;
  height: 100%;
  top: 0;
}
.split.left {
  position: absolute;
  left: 0;
  background-color: pink;
  background-image: url(https://m.media-amazon.com/images/I/61J9KUops4L._AC_UF1000,1000_QL80_.jpg);
  background-size: cover;
  background-position: 20px -70px;
}
.split.right {
  position: absolute;
  right: 0;
  background-color: lightblue;
  background-image: url(https://m.media-amazon.com/images/I/71nj3tkXZXL._AC_UF894,1000_QL80_.jpg);
  background-size: 100% 90%, 0 0;
  background-position: 10px 20px, 20px 10px;
  background-repeat: no-repeat;
}
.split.left .background-image {
  outline: none;
}
.active-left .left {
  width: 70%;
  background-position: 10px -80px;
}
.active-left .right {
  width: 40%;
}
.active-right .left {
  width: 50%;
}
.active-right .right {
  width: 70%;
}
.left,
.right {
  transition: width 2s ease-in-out;
}