#outer {
  overflow: hidden;
}

.balloon {
  display: inline-block;
  width: 120px;
  height: 145px;
  background: hsl(215, 50%, 65%);
  border-radius: 80%;
  position: relative;
  box-shadow: inset -10px -10px 0 rgba(0, 0, 0, 0.07);
  margin: 20px 30px;
  transition: transform 0.5s ease;
  z-index: 10;
  transform-origin: bottom center;
  opacity: 0.7;
  animation: moveUp 20s linear infinite, moveSideWays 4s ease-in-out infinite alternate, tilt 4.5s ease-in-out infinite;
}

@keyframes tilt {
  0%,
  100% {
    transform: translateY(0) rotate(-4deg);
  }

  50% {
    transform: translateY(-25px) rotate(4deg);
  }
}

@keyframes moveUp {
  0% {
    top: 1500px;
  }

  100% {
    top: -500px;
  }
}

@keyframes moveSideWays {
  0% {
    margin-left: 0px;
  }

  100% {
    margin-left: 50px;
  }
}

.balloon:before {
  content: "▲";
  font-size: 20px;
  color: hsl(215, 30%, 50%);
  display: block;
  text-align: center;
  width: 100%;
  position: absolute;
  bottom: -12px;
  z-index: -100;
}

.balloon:after {
  display: inline-block;
  top: 153px;
  left: 60px;
  position: absolute;
  height: 250px;
  width: 1px;
  margin: 0 auto;
  content: "";
  background: rgba(0, 0, 0, 0.2);
}

.balloon:nth-child(2) {
  background: hsl(24, 40%, 65%);
  opacity: 0.35;
  animation: moveUp 15s linear infinite, moveSideWays 4s ease-in-out infinite alternate, tilt 3.5s ease-in-out infinite;
}

.balloon:nth-child(2):before {
  color: hsl(24, 40%, 65%);
}

.balloon:nth-child(3) {
  background: hsl(139, 50%, 60%);
  opacity: 0.5;
  animation: moveUp 25s linear infinite, moveSideWays 5s ease-in-out infinite alternate, tilt 3s ease-in-out infinite;
}

.balloon:nth-child(3):before {
  color: hsl(139, 30%, 50%);
}

.balloon:nth-child(4) {
  background: hsl(59, 50%, 58%);
  opacity: 0.3;
  animation: moveUp 18s linear infinite, moveSideWays 2s ease-in-out infinite alternate, tilt 2.5s ease-in-out infinite;
}

.balloon:nth-child(4):before {
  color: hsl(59, 30%, 52%);
}

.balloon:nth-child(5) {
  background: hsl(23, 55%, 57%);
  opacity: 0.35;
  animation: moveUp 35s linear infinite, moveSideWays 3s ease-in-out infinite alternate, tilt 4s ease-in-out infinite;
}

.balloon:nth-child(5):before {
  color: hsl(23, 44%, 46%);
}

.balloon:nth-child(6) {
  background: hsl(102, 55%, 57%);
  opacity: 0.3;
  animation: moveUp 17s linear infinite, moveSideWays 1s ease-in-out infinite alternate, tilt 4.5s ease-in-out infinite;
}

.balloon:nth-child(6):before {
  color: hsl(102, 44%, 46%);
}
.balloon:nth-child(7) {
  background: hsl(220, 25%, 57%);
  opacity: 0.4;
  animation: moveUp 23s linear infinite, moveSideWays 2s ease-in-out infinite alternate, tilt 3.5s ease-in-out infinite;
}

.balloon:nth-child(7):before {
  color: hsl(220, 42%, 46%);
}

.balloon:nth-child(8) {
  background: hsl(73, 65%, 57%);
  opacity: 0.45;
  animation: moveUp 31s linear infinite, moveSideWays 2s ease-in-out infinite alternate, tilt 2.5s ease-in-out infinite;
}

.balloon:nth-child(8):before {
  color: hsl(73, 54%, 46%);
}