.download-box {
  background-color: #5f29b4;
  height: 200px;
  transform: translate(-50%, -50%);
}

.btn-download {
  border: 2px solid white;
  display: block;
  border-radius: 10px;
  overflow: hidden;
}

.aurora {
  background: #000;
  position: relative;
}
.aurora:before,
.aurora:after {
  content: "";
  display: block;
  position: absolute;
  width: 1px;
  height: 1px;
  border-radius: 100%;
  opacity: 0.18;
}
.aurora:before {
  box-shadow: 0 0 35vmax 35vmax #f00;
  animation: hue 5s 0s linear infinite, move1 10s 0s linear infinite;
}
.aurora:after {
  box-shadow: 0 0 35vmax 35vmax #0ff;
  animation: hue 10s 0s linear infinite, move2 20s 0s linear infinite;
}
@-moz-keyframes hue {
  0% {
    filter: hue-rotate(0deg);
  }
  100% {
    filter: hue-rotate(360deg);
  }
}
@-webkit-keyframes hue {
  0% {
    filter: hue-rotate(0deg);
  }
  100% {
    filter: hue-rotate(360deg);
  }
}
@-o-keyframes hue {
  0% {
    filter: hue-rotate(0deg);
  }
  100% {
    filter: hue-rotate(360deg);
  }
}
@keyframes hue {
  0% {
    filter: hue-rotate(0deg);
  }
  100% {
    filter: hue-rotate(360deg);
  }
}
@-moz-keyframes move1 {
  0% {
    top: 0vh;
    left: 50vw;
  }
  25% {
    left: 0vw;
  }
  50% {
    top: 100vh;
  }
  75% {
    left: 100vw;
  }
  100% {
    top: 0vh;
    left: 50vw;
  }
}
@-webkit-keyframes move1 {
  0% {
    top: 0vh;
    left: 50vw;
  }
  25% {
    left: 0vw;
  }
  50% {
    top: 100vh;
  }
  75% {
    left: 100vw;
  }
  100% {
    top: 0vh;
    left: 50vw;
  }
}
@-o-keyframes move1 {
  0% {
    top: 0vh;
    left: 50vw;
  }
  25% {
    left: 0vw;
  }
  50% {
    top: 100vh;
  }
  75% {
    left: 100vw;
  }
  100% {
    top: 0vh;
    left: 50vw;
  }
}
@keyframes move1 {
  0% {
    top: 0vh;
    left: 50vw;
  }
  25% {
    left: 0vw;
  }
  50% {
    top: 100vh;
  }
  75% {
    left: 100vw;
  }
  100% {
    top: 0vh;
    left: 50vw;
  }
}
@-moz-keyframes move2 {
  0% {
    top: 50vh;
    left: 100vw;
  }
  25% {
    top: 100vh;
  }
  50% {
    left: 0vw;
  }
  75% {
    top: 0vh;
  }
  100% {
    top: 50vh;
    left: 100vw;
  }
}
@-webkit-keyframes move2 {
  0% {
    top: 50vh;
    left: 100vw;
  }
  25% {
    top: 100vh;
  }
  50% {
    left: 0vw;
  }
  75% {
    top: 0vh;
  }
  100% {
    top: 50vh;
    left: 100vw;
  }
}
@-o-keyframes move2 {
  0% {
    top: 50vh;
    left: 100vw;
  }
  25% {
    top: 100vh;
  }
  50% {
    left: 0vw;
  }
  75% {
    top: 0vh;
  }
  100% {
    top: 50vh;
    left: 100vw;
  }
}
@keyframes move2 {
  0% {
    top: 50vh;
    left: 100vw;
  }
  25% {
    top: 100vh;
  }
  50% {
    left: 0vw;
  }
  75% {
    top: 0vh;
  }
  100% {
    top: 50vh;
    left: 100vw;
  }
}