<div class="container">
  <div class="sky"></div>
  <div class="sea">
  <div class="light"></div></div>

  <div class="sun"></div>
  <div class="bird1"></div>
  <div class="birdr1"></div>
  <div class="bird"></div>
  <div class="birdr"></div>
  <div class="fin">
  <div class="wave"></div></div>
</div>
html {
  background: black;
  overflow: hidden;
}

.container,
.sea,
.sky,
.sun,
.light,
.bird,
.birdr1,
.birdr,
.fin,
.wave {
  position: absolute;
}

.container {
  width: 100%;
  height: 400px;
  overflow: hidden;
  top: 50%;
  left: 50%;
  margin-left: -50%;
  margin-top: -200px;
}

.sky {
  opacity: .8;
  width: 100%;
  height: 50%;
  top: 0;
  background: radial-gradient(at 50% 70%, #820, #610, #400, #100);
  z-index: 30;
}

.sea {
  width: 100%;
  height: 50%;
  top: 50%;
  background: radial-gradient(at 50% 0%, #007, #004);
  z-index: 60;
}

.sun {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  left: 45%;
  z-index: 40;
  background: linear-gradient(#ff0, #d00);
  box-shadow: 0 0 40px 6px #f20, 0 0 150px 10px #f33;
  animation: rise 24s ease forwards;
}

@keyframes rise {
  0% {
    top: 50%;
  }
  100% {
    top: 15%;
  }
}

.light {
  opacity: .5;
  left: 0%;
  width: 100%;
  height: 100%;
  background: radial-gradient(at 50% 0%, #ff0, transparent);
  z-index: 60;
  animation: over 12s ease forwards;
}

@keyframes over {
  0% {
    opacity: 0
  }
  ;
  100% {
    opacity: .2
  }
  ;
}

.bird {
  opacity: 1;
  top: 50px;
  left: 00px;
  width: 10px;
  height: 8px;
  border: 2px solid black;
  border-radius: 50%;
  border-top-color: transparent;
  border-left-color: transparent;
  border-bottom-color: transparent;
  transform: rotateZ(-75deg);
  animation: move 25s linear infinite, flap .5s linear alternate infinite;
  z-index: 70;
}

.birdr {
  z-index: 70;
  
  opacity: 1;
  top: 50px;
  width: 10px;
  height: 8px;
  border: 2px solid black;
  border-radius: 50%;
  border-bottom-color: transparent;
  border-right-color: transparent;
  border-top-color: transparent;
  transform: rotateZ(75deg);
  margin: 0px 8px;
  animation: mover 25s linear infinite, flap .5s linear alternate infinite;
}

.bird1 {
  opacity: 1;
  top: 45px;
  left: 0px;
  width: 10px;
  height: 8px;
  border: 2px solid black;
  border-radius: 50%;
  border-top-color: transparent;
  border-left-color: transparent;
  border-bottom-color: transparent;
  transform: rotateZ(-90deg);
  animation: move 25s linear infinite 1.5s, flap .5s linear alternate infinite 1.5s;
  z-index: 70;
}

.birdr1 {
  z-index: 70;
  
  opacity: 1;
  top: 45px;
  width: 10px;
  height: 8px;
  border: 2px solid black;
  border-radius: 50%;
  border-bottom-color: transparent;
  border-right-color: transparent;
  border-top-color: transparent;
  transform: rotateZ(90deg);
  margin: 0px 8px;
  animation: mover 25s linear infinite 1.5s, flap .5s linear alternate infinite 1.5s;
}

.fin {
  border: 30px solid black;
  top: 90%;
  left: 100%;
  z-index: 100;
  border-left: 30px solid transparent;
  border-top: 0px solid transparent;
  border-right: 10px solid transparent;
  border-radius: 0px 0px 2px 10px;
  animation: swim 30s linear forwards 10s;
}

.wave {
  margin: 26px 7px;
  border-left: 3px solid transparent;
  border-top: 6px solid rgba(50, 50, 140, .3);
  border-right: 50px solid transparent;
  transform: rotatez(6deg);
  z-index: 60;
}

@keyframes swim {
  0% {
    left: 100%;
  }
  100% {
    left: -25%
  }
  ;
}

@keyframes move {
  0% {
    left: 0px;
  }
  100% {
    left: 100%;
  }
}

@keyframes mover {
  0% {
    left: -0px;
  }
  100% {
    left: 100%;
  }
}

@keyframes flap {
  0% {
    border-radius: 90%;
  }
  100% {
    border-radius: 10%;
  }
}
Rerun