Result

水上で起こる波紋のようなエフェクトです

css

html,
body {/*bodyの背景を波紋の色に合わせる*/
  margin: 0;
  background: #45c2c5;
}

.ripple,
.ripple:before,
.ripple:after {/*疑似要素も作り、3つの波紋を作る*/
  display: block;
  border-radius: 2px;
  width: 2px;
  height: 2px;
  animation: rip 6s infinite ease-out;
}
.ripple {
  position: absolute;
  z-index: -1;
  top: 40px;
  left: 15px;
}
.ripple:before,
.ripple:after {
  content: "";
  position: absolute;
}
.ripple:before {/*遅延させる*/
  animation-delay: 0.2s;
  top: 5px;
  left: 25px;
}
.ripple:after {/*さらに遅延*/
  animation-delay: 0.8s;
  top: 25px;
  left: 0;
}
@keyframes rip {/*keyframesで波紋セッティング*/
  0% {
    box-shadow: 0 0 0 0 transparent, 0 0 0 0 transparent, 0 0 0 0 transparent,
      0 0 0 0 transparent;
  }
  15% {
    box-shadow: 0 0 0 0 #45c2c5, 0 0 0 0 rgba(255, 255, 255, 0.4),
      0 0 0 0 #45c2c5, 0 0 0 0 rgba(0, 0, 0, 0.08);
  }
  100% {
    box-shadow: 0 0 40px 200px #45c2c5, 0 0 10px 210px transparent,
      0 0 30px 220px #45c2c5, 0 0 5px 230px transparent;
  }
}

html

<div>
  <h1>foo</h1>
  <span class="ripple"></span>
</div>

via

CSS ripple effect