/* ============================================
   BACK TO TOP
   ============================================ */
.back-to-top {
  position: fixed; bottom: 26px; right: 26px; width: 46px; height: 46px; border-radius: 50%;
  background: var(--ocean); color: #F4F6F5; border: none; font-size: 18px;
  display: flex; align-items: center; justify-content: center;
  opacity: 0; transform: translateY(10px); pointer-events: none;
  transition: opacity 0.25s ease, transform 0.25s ease, background 0.2s ease;
  z-index: 90;
}
.back-to-top.is-visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.back-to-top:hover { background: var(--ocean-deep); }