.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 60;
  display: grid;
  place-items: center;
  width: 3rem;
  height: 3rem;
  padding: 0;
  border: none;
  border-radius: 9999px;
  background: #0891b2;
  color: #fff;
  cursor: pointer;
  box-shadow:
    0 4px 14px rgba(8, 145, 178, 0.35),
    0 2px 6px rgba(0, 0, 0, 0.12);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px) scale(0.92);
  transition:
    opacity 0.25s cubic-bezier(0.25, 0.1, 0.25, 1),
    transform 0.25s cubic-bezier(0.25, 0.1, 0.25, 1),
    visibility 0.25s,
    background 0.2s,
    box-shadow 0.2s;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.back-to-top:hover {
  background: #0e7490;
  box-shadow:
    0 6px 20px rgba(8, 145, 178, 0.45),
    0 2px 8px rgba(0, 0, 0, 0.14);
  transform: translateY(-2px) scale(1.05);
}

.back-to-top:focus-visible {
  outline: 2px solid #0891b2;
  outline-offset: 3px;
}

.back-to-top svg {
  width: 1.25rem;
  height: 1.25rem;
}

@media (max-width: 640px) {
  .back-to-top {
    bottom: 1.25rem;
    right: 1.25rem;
    width: 2.75rem;
    height: 2.75rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .back-to-top {
    transition: opacity 0.15s, visibility 0.15s;
  }

  .back-to-top:hover {
    transform: none;
  }
}