.back-to-top {
  position: fixed;
  bottom: var(--space-8);
  right: var(--space-8);
  width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-full);
  background: var(--color-primary-400);
  color: var(--color-text-inverse);
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  pointer-events: none;
  transition: var(--transition-interactive), opacity var(--duration-moderate) var(--ease-out);
  z-index: 40;
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

.back-to-top:hover {
  box-shadow: var(--shadow-lg);
  background: var(--color-primary-500);
}

.back-to-top:active {
  box-shadow: var(--shadow-sm);
}

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

@media print {
  .back-to-top { display: none; }
}