.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 999;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
  color: var(--white);
  font-size: 1.25rem;
  font-weight: 800;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease, background 0.2s ease, border-color 0.2s ease;
}

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

.back-to-top:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.28);
}

.back-to-top.is-visible:hover {
  transform: translateY(-2px);
}

.back-to-top:focus-visible {
  outline: 3px solid var(--secondary);
  outline-offset: 4px;
}

@media (max-width: 860px) {
  .back-to-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 44px;
    height: 44px;
  }
}