* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
.container {
  height: 400px;
  width: 400px;
  background-color: black;
}
.animate-box {
  height: 50px;
  width: 50px;
  background-color: burlywood;
  position: absolute;
}

button {
  margin-top: 10px;
  padding: 5px 10px;
}