/* ═══════════════════════════════════════════
   BACK TO TOP — Gradient feel
   ═══════════════════════════════════════════ */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--blue-600), var(--indigo));
  color: #fff;
  border: none;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .3s, transform .3s, box-shadow .3s;
  box-shadow: 0 4px 16px rgba(99, 102, 241, .25);
  z-index: 999;
}

.back-to-top.show {
  opacity: 1;
  transform: none;
}

.back-to-top:hover {
  box-shadow: 0 8px 28px rgba(99, 102, 241, .35);
  transform: translateY(-2px);
}