<label><input class="bubble" type="checkbox" name="dummy" value="on"></label>

* {
  border: 0;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
:root {
  --bubbleTiming: cubic-bezier(0.5,0.15,0.25,1.75);
  font-size: calc(40px + (60 - 40) * (100vw - 320px) / (1280 - 320));
}
body, input {
  font: 1em/1.5 sans-serif;
}
body {
  background: hsl(223,90%,65%);
  display: grid;
  height: 100vh;
  place-items: center;
}
label, .bubble {
  display: block;
  -webkit-tap-highlight-color: transparent;
}
label {
  animation: float 4s ease-in-out infinite;
}
.bubble, .bubble:before, .bubble:after  {
  transition-duration: 0.2s;
}
.bubble, .bubble:after {
  border-radius: 50%;
}
.bubble {
  background-image:
    radial-gradient(8% 8% at 22% 28%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%),
    radial-gradient(8% 8% at 23% 27%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%),
    radial-gradient(8% 8% at 24% 26%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%),
    radial-gradient(8% 8% at 25% 25%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%),
    radial-gradient(8% 8% at 26% 24%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%),
    radial-gradient(8% 8% at 27% 23%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%),
    radial-gradient(8% 8% at 28% 22%,hsl(0,0%,100%) 45%,hsla(0,0%,100%,0) 50%);
  box-shadow:
    0 -0.06em 0.1em hsl(0,90%,100%) inset,
    0 -0.15em 0.4em hsl(0,90%,45%) inset,
    0 0.05em 0.05em hsl(0,90%,45%) inset,
    0.05em 0 0.1em hsl(0,90%,100%) inset,
    -0.05em 0 0.1em hsl(0,90%,100%) inset,
    0 0.1em 0.4em hsl(0,90%,60%) inset;
  cursor: pointer;
  position: relative;
  width: 3em;
  height: 3em;
  transform-style: preserve-3d;
  transition-property: box-shadow, transform, width, height;
  transition-timing-function: ease-in-out, ease-in-out, var(--bubbleTiming), var(--bubbleTiming);
  will-change: transform;
  -webkit-appearance: none;
  appearance: none;
  z-index: 0;
}
.bubble:before, .bubble:after {
  content: "";
  display: block;
  position: absolute;
  transition-timing-function: var(--bubbleTiming);
}
.bubble:before {
  border-radius: 0.75em;
  box-shadow:
    0 0 0 0.5em hsl(0,0%,100%) inset;
  filter: drop-shadow(0.6em 0.6em 4px hsla(0,0%,0%,0.2));
  top: 50%;
  left: 50%;
  width: 1.5em;
  height: 1.5em;
  transform: translate3d(-50%,-50%,-1px);
  z-index: -1;
}
.bubble:after {
  background:
    radial-gradient(100% 100% at center,hsla(0,0%,0%,0) 35%,hsla(0,0%,0%,0.2) 48%,hsla(0,0%,0%,0) 50%);
  filter: blur(4px);
  top: 0.6em;
  left: 0.6em;
  width: 100%;
  height: 100%;
  transform: translate3d(0,0,-1px);
  z-index: -2;
}
.bubble:focus, .bubble:hover {
  transform: scale(1.1);
  outline: none;
}
.bubble:focus:active, .bubble:hover:active {
  width: 3.6em;
  height: 2.4em;
}
.bubble:focus:before, .bubble:hover:before {
  filter: drop-shadow(0.75em 0.75em 4px hsla(0,0%,0%,0.2));
}
.bubble:focus:after, .bubble:hover:after {
  transform: translate3d(0.15em,0.15em,-1px);
}
.bubble:checked {
  box-shadow:
    0 -0.06em 0.1em hsl(120,90%,100%) inset,
    0 -0.15em 0.4em hsl(120,90%,45%) inset,
    0 0.05em 0.05em hsl(120,90%,45%) inset,
    0.05em 0 0.1em hsl(120,90%,100%) inset,
    -0.05em 0 0.1em hsl(120,90%,100%) inset,
    0 0.1em 0.4em hsl(120,90%,60%) inset;
}
.bubble:checked:before {
  border-radius: 0.25em;
  width: 0.5em;
}
/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  label {
    animation: none;
  }
  .bubble, .bubble:before, .bubble:after {
    transition-duration: 0s;
  }
  .bubble:focus, .bubble:hover {
    transform: scale(1);
  }
  .bubble:focus:active, .bubble:hover:active {
    width: 3em;
    height: 3em;
  }
  .bubble:focus:before, .bubble:hover:before {
    filter: drop-shadow(0.6em 0.6em 4px hsla(0,0%,0%,0.2));
  }
  .bubble:focus:after, .bubble:hover:after {
    transform: translate3d(0,0,-1px);
  }
}
/* Animations */
@keyframes float {
  from, to {
    transform: translate(0,3%);
  }
  25% {
    transform: translate(-3%,0);
  }
  50% {
    transform: translate(0,-3%);
  }
  75% {
    transform: translate(3%,0);
  }
}