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HTML 

              
                <h2>Cuckoo Clock CSS Animation with Sound</h2>

<div id="clock" class="clock">
  <audio id="cuckooSound" src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/123941/cuckoo-sound.mp3" preload="auto">
    Your browser does not support the <code>audio</code> element.
  </audio>
  <div class="cuckoo-head">
    <div class="eye1"></div>
    <div class="eye2"></div>

    <div class="beak-container"></div>
  </div>
</div>

<div class="buttons">
  <button id="play">Play</button>
  <button id="reset">Reset</button>
</div>

<p class="p">Demo by Mihaela Jurkovic. <a href="http://www.sitepoint.com/syncing-css-animations-with-html5-audio" target="_blank">See article</a>.</p>
!

CSS 

              
                body {
  background-color: #222;
  color: #eaeaea;
  margin: 0;
  overflow: hidden;
  padding: 1em;
  text-align: center;
}
/**
 *   Clock container
 *   Change the size here
 */

.clock {
  background-color: black;
  border: 10px ridge black;
  border-color: #ccc #333 #111 #999;
  border-radius: 8%;
  height: 300px;
  margin: 3em auto 1em;
  perspective: 700px;
  perspective-origin: center;
  position: relative;
  /* context for pseudo elements */
  
  text-align: center;
  width: 300px;
}
/**
 *   door
 */

.clock::after {
  background-color: goldenrod;
  border-radius: 5%;
  content: "";
  height: 100%;
  left: 0;
  position: absolute;
  top: 0;
  /* performance boost hardware acceleration activated in 3D */
  
  transform: translateZ(0);
  transform-origin: 100% 100%;
  width: 100%;
}

.cuckoo-head {
  background: #1f1f1f;
  /* Old browsers */
  
  background: linear-gradient(to bottom, #1f1f1f 0%, #7d7e7d 100%);
  border-radius: 50% 50% 25% 25%/50% 50% 50% 50%;
  height: 80%;
  left: 50%;
  margin-left: -40%;
  margin-top: -40%;
  position: absolute;
  top: 55%;
  width: 80%;
}
/**
 *   feather
 */

.clock::before {
  border-radius: 50%;
  box-shadow: 1em 1em 0 0 #1f1f1f;
  content: "";
  display: block;
  height: 30%;
  left: 20%;
  position: absolute;
  top: -6%;
  width: 30%;
  z-index: -1;
}

.eye1,
.eye2 {
  background-color: yellow;
  border-radius: 50%;
  box-shadow: 0 -2px 5px black;
  height: 10%;
  left: 30%;
  position: absolute;
  top: 30%;
  width: 10%;
}

.eye2 {
  left: 60%;
}

.eye1::after,
.eye2::after {
  background-color: black;
  border-radius: 50%;
  content: "";
  display: block;
  height: 60%;
  left: 20%;
  position: absolute;
  top: 30%;
  width: 60%;
}

.beak-container {
  height: 40%;
  left: 30%;
  position: absolute;
  top: 40%;
  /* animation rotation will be applied to the container */
  
  transform: translateZ(0) rotateX(0);
  width: 40%;
}

.beak-container::after {
  background: #febf04;
  /* Old browsers */
  
  background: linear-gradient(135deg, #febf04 0%, #ffd65e 100%);
  border-top-left-radius: 20%;
  border-top-right-radius: 5%;
  border-bottom-right-radius: 75%;
  border-bottom-left-radius: 5%;
  box-shadow: -1px -1px 5px black;
  content: "";
  left: 0;
  position: absolute;
  height: 100%;
  top: 0;
  width: 100%;
  /** position the beak right side up */
  
  transform: rotate(45deg);
}

.clock.active::after {
  animation: door 2.1s linear 0s 1;
}

.clock.active .cuckoo-head {
  animation: head 2.1s linear 0s 1;
}

.clock.active .beak-container {
  animation: beak 2.1s linear 0s 1;
}

.#clock.active .eye1,
.clock.active .eye2 {
  animation: eyes 2.1s linear 0s 1;
}

.clock.active::before {
  animation: feather 2.1s linear 0s 1;
}

@keyframes door {
  0% {
    background-color: goldenrod;
    transform: translateZ(0) rotateY(0deg);
  }
  14% {
    background-color: #5d0000;
    transform: translateZ(0) rotateY(90deg);
  }
  31% {
    background-color: #5d0000;
    transform: translateZ(0) rotateY(90deg);
  }
  33% {
    background-color: goldenrod;
    transform: translateZ(0) rotateY(0deg);
  }
}

@keyframes head {
  14% {
    transform: translateZ(0) scaleY(1);
  }
  23% {
    transform: translateZ(0) scaleY(0.9);
  }
  31% {
    transform: translateZ(0) scaleY(1);
  }
}

@keyframes beak {
  14% {
    transform: translateZ(0) rotateX(0);
  }
  23% {
    transform: translateZ(0) rotateX(60deg);
  }
  31% {
    transform: translateZ(0) rotateX(0);
  }
}

@keyframes eyes {
  14% {
    transform: translateZ(0) scaleY(1);
  }
  23% {
    transform: translateZ(0) scaleY(0.3);
  }
  31% {
    transform: translateZ(0) scaleY(1);
  }
}

@keyframes feather {
  14% {
    transform: translateZ(0) scaleY(1);
    top: -6%;
  }
  23% {
    transform: translateZ(0) scaleY(0.5);
    top: 3%;
  }
  31% {
    transform: translateZ(0) scaleY(1);
    top: -6%;
  }
}

.buttons {
  text-align: center;
  color: black;
}

button {
  padding: 4px 16px;
}

.p {
  text-align: center;
  font-size: 13px;
  padding-top: 120px;
}

.p a {
  color: white;
}
!

JS 

              
                var playBtn = document.getElementById('play'),
  resetBtn = document.getElementById('reset'),
  standrew = document.getElementById('clock'),
  cuckooSound = document.getElementById('cuckooSound');

playBtn.addEventListener('click', function() {
  if (!clock.classList.contains('active')) {
    clock.classList.add('active');
    cuckooSound.play();
  }
}, false);

resetBtn.addEventListener('click', function() {
  clock.classList.remove('active');
  cuckooSound.pause();
  cuckooSound.currentTime = 0;
}, false);
!
999px

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