@keyframes firework {
  0% {
    transform: translate(var(--x), var(--initialY));
    width: var(--initialSize);
    opacity: 1;
  }
  50% {
    width: 0.5vmin;
    opacity: 1;
  }
  100% {
    width: var(--finalSize);
    opacity: 0;
  }
}

.firework,
.firework::before,
.firework::after {
  --initialSize: 0.5vmin;
  --finalSize: 45vmin;
  --particleSize: 0.2vmin;
  --color1: yellow;
  --color2: khaki;
  --color3: white;
  --color4: lime;
  --color5: gold;
  --color6: mediumseagreen;
  --y: -30vmin;
  --x: -50%;
  --initialY: 60vmin;
  content: "";
  opacity: 0;
  animation: firework 2s 2 forwards;
  pointer-events: none;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, var(--y));
  width: var(--initialSize);
  aspect-ratio: 1;
  background:
        radial-gradient(
        circle,
        var(--color1) var(--particleSize),
        #0000 0
      )
      50% 0%,
    radial-gradient(circle, var(--color2) var(--particleSize), #0000 0) 100% 50%,
    radial-gradient(circle, var(--color3) var(--particleSize), #0000 0) 50% 100%,
    radial-gradient(circle, var(--color4) var(--particleSize), #0000 0) 0% 50%,
    /* bottom right */
      radial-gradient(circle, var(--color5) var(--particleSize), #0000 0) 80%
      90%,
    radial-gradient(circle, var(--color6) var(--particleSize), #0000 0) 95% 90%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 90% 70%,
    radial-gradient(circle, var(--color2) var(--particleSize), #0000 0) 100% 60%,
    radial-gradient(circle, var(--color3) var(--particleSize), #0000 0) 55% 80%,
    radial-gradient(circle, var(--color4) var(--particleSize), #0000 0) 70% 77%,
    /* bottom left */
      radial-gradient(circle, var(--color5) var(--particleSize), #0000 0) 22%
      90%,
    radial-gradient(circle, var(--color6) var(--particleSize), #0000 0) 45% 90%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 33% 70%,
    radial-gradient(circle, var(--color2) var(--particleSize), #0000 0) 10% 60%,
    radial-gradient(circle, var(--color3) var(--particleSize), #0000 0) 31% 80%,
    radial-gradient(circle, var(--color4) var(--particleSize), #0000 0) 28% 77%,
    radial-gradient(circle, var(--color5) var(--particleSize), #0000 0) 13% 72%,
    /* top left */
      radial-gradient(circle, var(--color6) var(--particleSize), #0000 0) 80%
      10%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 95% 14%,
    radial-gradient(circle, var(--color2) var(--particleSize), #0000 0) 90% 23%,
    radial-gradient(circle, var(--color3) var(--particleSize), #0000 0) 100% 43%,
    radial-gradient(circle, var(--color4) var(--particleSize), #0000 0) 85% 27%,
    radial-gradient(circle, var(--color5) var(--particleSize), #0000 0) 77% 37%,
    radial-gradient(circle, var(--color6) var(--particleSize), #0000 0) 60% 7%,
    /* top right */
      radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 22%
      14%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 45% 20%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 33% 34%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 10% 29%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 31% 37%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 28% 7%,
    radial-gradient(circle, var(--color1) var(--particleSize), #0000 0) 13% 42%;
  background-size: var(--initialSize) var(--initialSize);
  background-repeat: no-repeat;
}

.firework::before {
  --x: -50%;
  --y: -50%;
  --initialY: -50%;
  transform: translate(-50%, -50%) rotate(40deg) scale(1.3) rotateY(40deg);
}

.firework::after {
  --x: -50%;
  --y: -50%;
  --initialY: -50%;
  transform: translate(-50%, -50%) rotate(170deg) scale(1.15) rotateY(-30deg);
}

.firework:nth-child(2) {
  --x: 30vmin;
}

.firework:nth-child(2),
.firework:nth-child(2)::before,
.firework:nth-child(2)::after {
  --finalSize: 40vmin;
  left: 35%;
  top: 60%;
  animation-delay: 0.4s;
}

.firework:nth-child(3) {
  --x: -30vmin;
  --y: -50vmin;
}

.firework:nth-child(3),
.firework:nth-child(3)::before,
.firework:nth-child(3)::after {
  --finalSize: 35vmin;
  left: 60%;
  top: 60%;
  animation-delay: 0.8s;
}

.firework:nth-child(4),
.firework:nth-child(4)::before,
.firework:nth-child(4)::after {
  --finalSize: 50vmin;
  left: 50%;
  top: 30%;
  animation-delay: 1.2s;
}

.firework:nth-child(5),
.firework:nth-child(5)::before,
.firework:nth-child(5)::after {
  --finalSize: 60vmin;
  left: 40%;
  top: 80%;
  animation-delay: 1.4s;
}

.firework:nth-child(6),
.firework:nth-child(6)::before,
.firework:nth-child(6)::after {
  --finalSize: 40vmin;
  left: 50%;
  top: 90%;
  animation-delay: 1.8s;
}