/* =========================================================
   Back-to-top button - liquid glass, responsive sizing
   Breakpoints:
     base:           mobile portrait (<= 600px)        -> 44px circle
     601-900px:      large phone / phablet             -> 48px circle
     >= 901px:       desktop & tablet (any orientation) -> 52px circle
   Mobile landscape (<= 900px & landscape): tighter insets
   ========================================================= */
.back-to-top {
  position: fixed;
  right: 16px;
  bottom: 16px;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 50%;
  background: rgba(20, 20, 20, 0.45);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  box-shadow:
    0 8px 32px rgba(0, 0, 0, 0.28),
    inset 0 1px 0 rgba(255, 255, 255, 0.12);
  color: #fff;
  cursor: pointer;
  z-index: 50;
  opacity: 0;
  transform: translateY(8px) scale(0.96);
  transition:
    opacity 0.25s ease,
    transform 0.25s ease,
    background 0.2s ease,
    box-shadow 0.2s ease;
}
.back-to-top svg {
  width: 56%;
  height: 56%;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.back-to-top.is-visible { opacity: 1; transform: translateY(0) scale(1); }
.back-to-top:hover {
  background: rgba(255, 255, 255, 0.18);
  box-shadow:
    0 10px 36px rgba(0, 0, 0, 0.32),
    inset 0 1px 0 rgba(255, 255, 255, 0.2);
}
.back-to-top:focus-visible { outline: 2px solid var(--yellow); outline-offset: 3px; }
.back-to-top:active { transform: translateY(0) scale(0.94); }
@media (min-width: 601px) {
  .back-to-top { right: 20px; bottom: 20px; width: 48px; height: 48px; }
}
@media (min-width: 901px) {
  .back-to-top { right: 28px; bottom: 28px; width: 52px; height: 52px; }
}
@media (max-width: 900px) and (orientation: landscape) {
  .back-to-top { right: 12px; bottom: 12px; width: 40px; height: 40px; }
}
@media (prefers-reduced-motion: reduce) { .back-to-top { transition: none; } }


/* =========================================================
   Hero loader (spinner) + scroll lock
   - Body has class="is-loading" until the hero video has primed
   - Spinner sits in the centre of the hero stage
   - When ready, JS removes is-loading, fades out the loader
   ========================================================= */
body.is-loading { overflow: hidden; touch-action: none; }
body.is-loading .hero-stage,
body.is-loading .scrub-stage { cursor: wait; }

.hero-loader {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  z-index: 5;
  pointer-events: none;
  transition: opacity 0.45s ease;
}
.hero-loader.is-hidden { opacity: 0; }

.hero-loader-ring {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: 3px solid rgba(255, 255, 255, 0.12);
  border-top-color: var(--yellow);
  border-right-color: rgba(245, 197, 24, 0.45);
  animation: hero-loader-spin 0.9s cubic-bezier(0.65, 0, 0.35, 1) infinite;
  filter: drop-shadow(0 0 12px rgba(245, 197, 24, 0.35));
}
.hero-loader-text {
  position: absolute;
  bottom: 18%;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.78rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
}
@keyframes hero-loader-spin { to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) {
  .hero-loader-ring { animation-duration: 2.4s; }
  .hero-loader { transition: none; }
}