Css3 Animation 动画原则十二

<h1>Principle 12: Appeal</h1>
<h2><a href="https://cssanimation.rocks/principles/" target="_parent">Animation Principles for the Web</h2>
<article class="principle twelve">
    <div class="shape">
      <div class="container">
        <span class="item one"></span>
        <span class="item two"></span>
        <span class="item three"></span>
        <span class="item four"></span>
      </div>
    </div>
</article>

.twelve .shape {
  background: none;
  border: none;
  perspective: 400px;
  perspective-origin: center;
}

.twelve .shape .container {
  animation: show-container 8s infinite cubic-bezier(.6,-0.44,.37,1.44);
  transform-style: preserve-3d;
  width: 4em;
  height: 4em;
  border: 1em solid #fff;
  background: #2d97db;
  position: relative;
}

.twelve .item {
  background-color: #1f7bb6;
  position: absolute;
}

.twelve .item.one {
  animation: show-text 8s 0.1s infinite ease-out;
  height: 6%;
  width: 30%;
  top: 15%;
  left: 25%;
}

.twelve .item.two {
  animation: show-text 8s 0.2s infinite ease-out;
  height: 6%;
  width: 20%;
  top: 30%;
  left: 25%;
}

.twelve .item.three {
  animation: show-text 8s 0.3s infinite ease-out;
  height: 6%;
  width: 50%;
  top: 45%;
  left: 25%;
}

.twelve .item.four {
  animation: show-button 8s infinite cubic-bezier(.64,-0.36,.1,1.43);
  height: 20%;
  width: 40%;
  top: 65%;
  left: 30%;
}

@keyframes show-container {
  0% {
    opacity: 0;
    transform: rotateX(-90deg);
  }
  10% {
    opacity: 1;
    transform: none;
    width: 4em;
    height: 4em;
  }
  15%, 90% {
    width: 12em;
    height: 12em;
    transform: translate(-4em, -4em);
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: rotateX(-90deg);
    width: 4em;
    height: 4em;
  }
}

@keyframes show-text {
  0%, 15% {
    transform: translateY(1em);
    opacity: 0;
  }
  20%, 85% {
    opacity: 1;
    transform: none;
  }
  88%, 100% {
    opacity: 0;
    transform: translateY(-1em);
    animation-timing-function: cubic-bezier(.64,-0.36,.1,1.43);
  }
}

@keyframes show-button {
  0%, 25% {
    transform: scale(0);
    opacity: 0;
  }
  35%, 80% {
    transform: none;
    opacity: 1;
  }
  90%, 100% {
    opacity: 0;
    transform: scale(0);
  }
}

/* General styling */
body {
  margin: 0;
  background: #e9b59f;
  font-family: HelveticaNeue, Arial, Sans-serif;
  color: #fff;
}

h1 {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  text-align: center;
  font-weight: 300;
}

h2 {
  font-size: 0.75em;
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  text-align: center;
}

a {
  text-decoration: none;
  color: #333;
}

.principle {
  width: 100%;
  height: 100vh;
  position: relative;
}

.shape {
  background: #2d97db;
  border: 1em solid #fff;
  width: 4em;
  height: 4em;
  position: absolute;
  top: calc(50% - 2em);
  left: calc(50% - 2em);
}