.btn-bubble {
  color: white;
  background-color: #77b11c;
  background-repeat: no-repeat;
}
.btn-bubble:hover, .btn-bubble:focus {
  -webkit-animation: bubbles 1s forwards ease-out;
          animation: bubbles 1s forwards ease-out;
  background: radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 90% 90% / 0.88em 0.88em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 23% 141% / 0.81em 0.81em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 17% 90% / 0.68em 0.68em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 15% 94% / 1.12em 1.12em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 42% 126% / 0.86em 0.86em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 102% 120% / 0.58em 0.58em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 12% 121% / 0.67em 0.67em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 69% 87% / 1.18em 1.18em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 32% 99% / 0.79em 0.79em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 84% 129% / 0.79em 0.79em, radial-gradient(circle at center, rgba(0, 0, 0, 0) 30%, #eeeeff 60%, #eeeeff 65%, rgba(0, 0, 0, 0) 70%) 40% 99% / 0.72em 0.72em;
  background-color: #77b11c;
  background-repeat: no-repeat;
}

@-webkit-keyframes bubbles {
  100% {
    background-position: 92% -220%, 31% -185%, 24% 6%, 16% -328%, 39% -366%, 110% -375%, 5% -60%, 59% -365%, 41% -363%, 82% -8%, 37% -224%;
    box-shadow: inset 0 -6.5em 0 #0072c4;
  }
}

@keyframes bubbles {
  100% {
    background-position: 92% -220%, 31% -185%, 24% 6%, 16% -328%, 39% -366%, 110% -375%, 5% -60%, 59% -365%, 41% -363%, 82% -8%, 37% -224%;
    box-shadow: inset 0 -6.5em 0 #0072c4;
  }
}
body {
  background: #10192d;
  display: flex;
  min-height: 100vh;
  justify-content: center;
  align-content: center;
  align-items: center;
}

.btn {
  display: inline-block;
  text-decoration: none;
  padding: 1em 2em;
}