Hi

body, html {
  margin: 0;
  padding: 0;
  overflow: hidden;
  height: 100%;
}

.ocean {
  height: 100%;
  width: 100%;background: linear-gradient(to bottom, #2b65af, #2a4e91);
  position: absolute;
  bottom: 0;
  left: 0;
}

.boat {
  position: absolute;
  bottom: 10%;
  left: 50%;transform: translateX(-50%);
  animation: boatAnimation 5s linear infinite;
}

@keyframes boatAnimation {
  0%, 100% {
    transform: translateX(-50%) translateY(0);
  }
  50% {
    transform: translateX(-50%) translateY(-10px);
  }
}