<div class="ocean">
  <div class="wave"></div>
  <div class="wave"></div>
  <div class="wave"></div>
</div>

/* for the pen */
html, body {
  margin: 0;
  min-height: 100%;
  background-color: #f2f2f2;
}

/* waves */
.ocean {
  height: 80px; /* change the height of the waves here */
  width: 100%;
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  overflow-x: hidden;
}

.wave {
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 800 88.7'%3E%3Cpath d='M800 56.9c-155.5 0-204.9-50-405.5-49.9-200 0-250 49.9-394.5 49.9v31.8h800v-.2-31.6z' fill='%23003F7C'/%3E%3C/svg%3E");
  position: absolute;
  width: 200%;
  height: 100%;
  animation: wave 10s -3s linear infinite;
  transform: translate3d(0, 0, 0);
  opacity: 0.8;
}

.wave:nth-of-type(2) {
  bottom: 0;
  animation: wave 18s linear reverse infinite;
  opacity: 0.5;
}

.wave:nth-of-type(3) {
  bottom: 0;
  animation: wave 20s -1s linear infinite;
  opacity: 0.5;
}

@keyframes wave {
    0% {transform: translateX(0);}
    50% {transform: translateX(-25%);}
    100% {transform: translateX(-50%);}
}