body {
  background: #f0f0f0;
  margin: 0;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
#container {
  position: relative;
  width: 500px;
  height: 500px;
}
#faceCanvas {
  background: #fffbe7;
  border-radius: 50%;
  box-shadow: 0 4px 32px rgba(0,0,0,0.12);
  display: block;
  margin: 0 auto;
}
#emoji-fireworks {
  pointer-events: none;
  position: absolute;
  left: 0; top: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
}
.emoji-burst {
  position: absolute;
  font-size: 2.2rem;
  opacity: 1;
  transition: transform 1.2s cubic-bezier(.4,2,.6,1), opacity 1.2s;
  will-change: transform, opacity;
}