menu {
  --size: 1.2rem;
  --radius: 6rem;
  --padding: 1rem;
  --bg-color: rgba(255, 255, 255, 0.1);
  --fg-color: rgba(0, 0, 0, 1);
  --hi-color: #12192c;
  font-size: 29px;
  position: fixed;
  bottom: var(--padding);
  right: var(--padding);
}

menu > * {
  position: absolute;
  
  display: grid;
  place-content: center;
  
  border-radius: 50%;
  font-size: 29px;
  background: var(--bg-color);
  color: var(--fg-color);
  
  text-decoration: none;
  
  box-shadow: 0px 0px 9px 0px rgba(0, 0, 0, 0.6);
}

menu > .action {
  --factor: 0;
  width: 2.5rem;
  height: 2.5rem;
  right: calc(1.35 * var(--size));
  bottom: calc(1.35 * var(--size));
  
  opacity: 0;
  
  transform: rotate(calc(-1 * var(--angle))) translateY(calc(-1 * var(--radius) * var(--factor))) rotate(var(--angle));
  
  transition: transform 250ms ease-in-out, opacity 250ms ease-in-out, box-shadow 250ms ease-in-out, color 250ms ease-in-out;
}

menu > .action:hover, menu > .trigger:hover {
  color: var(--hi-color);
  box-shadow: 0px 0px 0px 0.35rem rgba(0, 0, 0, 0.2);
}

menu.open > .action {
  --factor: 1;
  font-size: 20px;
  opacity: 1;
}

menu > .action:nth-child(1) {
  --angle: 0deg;
  transition-delay: 0ms;
}

menu > .action:nth-child(2) {
  --angle: 30deg;
  transition-delay: 50ms;
}

menu > .action:nth-child(3) {
  --angle: 60deg;
  transition-delay: 100ms;
}

menu > .action:nth-child(4) {
  --angle: 90deg;
  transition-delay: 150ms;
}

menu > .trigger {
  width: calc(1.9 * var(--size));
  height: calc(1.9 * var(--size));
  bottom: 0;
  right: 0;
  
  font-size: 2rem;
  transition: box-shadow 250ms ease-in-out, color 250ms ease-in-out;
}

menu > .trigger > i {
  transition: transform 250ms ease-in-out;
}

menu.open > .trigger > i {
  transform: rotate(-135deg);
}