.mouse {
  position: absolute;
  top: 75%;
  margin: 50px auto;
}

.mouse-icon {
  width: 25px;
  height: 45px;
  border: 2px solid white;
  border-radius: 15px;
  cursor: pointer;
  position: relative;
  text-align: center;
}

.mouse-wheel {
  height: 6px;
  margin: 2px auto 0;
  display: block;
  width: 3px;
  background-color: white;
  border-radius: 50%;
  -webkit-animation: 1.6s ease infinite wheel-up-down;
  -moz-animation: 1.6s ease infinite wheel-up-down;
  animation: 1.6s ease infinite wheel-up-down;
}

@keyframes wheel-up-down {
  0% {
    margin-top: 2px;
    opacity: 0;
  }
  30% {
    opacity: 1;
  }
  100% {
    margin-top: 20px;
    opacity: 0;
  }
}