/* ── Open Studio Video ── */
.os-video-section {
  padding: 0 2rem 6rem;
  max-width: 1200px;
  margin: 0 auto;
}
.os-video-label {
  display: block;
  font-size: 0.6rem;
  font-weight: 600;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.35);
  margin-bottom: 0.75rem;
}
.os-video-title {
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 300;
  font-style: italic;
  font-family: 'Cormorant Garamond', Georgia, serif;
  line-height: 1;
  margin-bottom: 0.5rem;
  color: #fff;
  letter-spacing: -0.01em;
}
.os-video-sub {
  font-size: 0.82rem;
  color: rgba(255,255,255,0.4);
  margin-bottom: 2.5rem;
  line-height: 1.6;
  max-width: 480px;
}
.os-video-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #111;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.08);
}
.os-vid-player-div {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
}
.os-vid-player-div iframe {
  position: absolute;
  bottom: 0; left: 0;
  width: 100%; height: 100%;
  border: none;
  transform: scale(1.22);
  transform-origin: center bottom; /* anchor to bottom — crops the opening frame at the top */
  pointer-events: none;
}
.os-vid-block-overlay {
  position: absolute;
  inset: 0;
  z-index: 10;
  background: transparent;
}
.os-vid-sound-btn {
  position: absolute;
  bottom: 1rem; right: 1rem;
  z-index: 20;
  background: rgba(5,5,5,0.72);
  border: 1px solid rgba(255,255,255,0.18);
  color: #fff;
  width: 2.6rem; height: 2.6rem;
  border-radius: 50%;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  transition: all 0.25s;
  backdrop-filter: blur(10px);
}
.os-vid-sound-btn:hover { border-color: rgba(255,255,255,0.5); background: rgba(5,5,5,0.92); }
.os-vid-sound-btn.unmuted { border-color: #FF5C8D; color: #FF5C8D; }
@media (max-width: 640px) {
  .os-video-section { padding: 0 1rem 4rem; }
}

/* ── Book Simulator ── */
    .book-section {
      padding: 0 2rem 8rem;
      max-width: 1200px;
      margin: 0 auto;
    }
    .book-section-label {
      display: block;
      font-size: 0.6rem;
      font-weight: 600;
      letter-spacing: 0.3em;
      text-transform: uppercase;
      color: rgba(255,255,255,0.35);
      margin-bottom: 0.75rem;
    }
    .book-section-title {
      font-size: clamp(1.8rem, 4vw, 3rem);
      font-weight: 300;
      font-style: italic;
      font-family: 'Cormorant Garamond', Georgia, serif;
      line-height: 1;
      margin-bottom: 0.5rem;
      color: #fff;
      letter-spacing: -0.01em;
    }
    .book-section-sub {
      font-size: 0.82rem;
      color: rgba(255,255,255,0.4);
      margin-bottom: 3rem;
      line-height: 1.6;
      max-width: 480px;
    }
    .book-stage {
      position: relative;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 1.5rem;
    }
    .book-outer {
      position: relative;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 2rem;
    }
    .book-arrow {
      background: none;
      border: 1px solid rgba(255,255,255,0.15);
      color: rgba(255,255,255,0.5);
      width: 2.4rem; height: 2.4rem;
      border-radius: 50%;
      font-size: 0.9rem;
      cursor: pointer;
      display: flex; align-items: center; justify-content: center;
      transition: all 0.25s;
      flex-shrink: 0;
    }
    .book-arrow:hover { border-color: rgba(255,255,255,0.5); color: #fff; }
    .book-arrow:disabled { opacity: 0.15; cursor: default; }

    /* 3D book engine */
    :root {
      --bk-page-w: 400px;
      --bk-page-h: 540px;
    }
    .book-container {
      position: relative;
      width: calc(var(--bk-page-w) * 2);
      height: var(--bk-page-h);
      perspective: 2800px;
      flex-shrink: 0;
    }
    .book-left-bg {
      position: absolute;
      top: 0; left: 0;
      width: 50%; height: 100%;
      background: #0c0c0c;
      border: 1px solid rgba(255,255,255,0.06);
      box-sizing: border-box;
    }
    .bk-page {
      position: absolute;
      top: 0; right: 0;
      width: 50%; height: 100%;
      transform-origin: left center;
      transform-style: preserve-3d;
      transition: transform 1.1s cubic-bezier(0.64, 0.04, 0.35, 1);
    }
    .bk-page.flipped { transform: rotateY(-180deg); }
    .bk-front, .bk-back {
      position: absolute;
      inset: 0;
      backface-visibility: hidden;
      overflow: hidden;
      background: #0c0c0c;
      border: 1px solid rgba(255,255,255,0.06);
      box-sizing: border-box;
    }
    .bk-back { transform: rotateY(180deg); }
    .bk-front img, .bk-back img {
      width: 100%; height: 100%;
      object-fit: cover; display: block;
    }
    /* Spine shadow */
    .bk-front::after {
      content: '';
      position: absolute; top: 0; left: 0;
      width: 40px; height: 100%;
      background: linear-gradient(to right, rgba(0,0,0,0.25), transparent);
      pointer-events: none;
    }
    .bk-back::after {
      content: '';
      position: absolute; top: 0; right: 0;
      width: 40px; height: 100%;
      background: linear-gradient(to left, rgba(0,0,0,0.25), transparent);
      pointer-events: none;
    }
    .book-pagination {
      font-size: 0.6rem;
      letter-spacing: 0.22em;
      text-transform: uppercase;
      color: rgba(255,255,255,0.25);
    }
    .book-key-hint {
      font-size: 0.58rem;
      letter-spacing: 0.15em;
      color: rgba(255,255,255,0.18);
      text-transform: uppercase;
    }
    @media (max-width: 1000px) {
      :root { --bk-page-w: 280px; --bk-page-h: 380px; }
      .book-arrow { width: 2rem; height: 2rem; font-size: 0.75rem; }
    }
    @media (max-width: 640px) {
      :root { --bk-page-w: 155px; --bk-page-h: 210px; }
      .book-section { padding: 0 1rem 5rem; }
      .book-outer { gap: 0.75rem; }
    }

    /* ── Feedback Sticky Notes ── */
    .feedback-section {
      padding: 0 2rem 10rem;
      max-width: 1200px;
      margin: 0 auto;
    }
    .feedback-section-label {
      display: block;
      font-size: 0.6rem;
      font-weight: 600;
      letter-spacing: 0.3em;
      text-transform: uppercase;
      color: rgba(255,255,255,0.35);
      margin-bottom: 0.75rem;
    }
    .feedback-section-title {
      font-size: clamp(1.8rem, 4vw, 3rem);
      font-weight: 300;
      font-style: italic;
      font-family: 'Cormorant Garamond', Georgia, serif;
      line-height: 1;
      margin-bottom: 0.5rem;
      color: #fff;
      letter-spacing: -0.01em;
    }
    .feedback-section-sub {
      font-size: 0.82rem;
      color: rgba(255,255,255,0.4);
      margin-bottom: 2.5rem;
      line-height: 1.6;
      max-width: 480px;
    }
    .feedback-board {
      position: relative;
      width: 100%;
      min-height: 560px;
      border: 1px solid rgba(255,255,255,0.06);
      border-radius: 6px;
      background-image: radial-gradient(rgba(255,255,255,0.04) 1px, transparent 1px);
      background-size: 24px 24px;
      overflow: hidden;
    }
    .fb-note {
      position: absolute;
      width: 240px;
      background: rgba(20,20,20,0.92);
      border: 1px solid rgba(255,255,255,0.1);
      padding: 28px 20px 20px 20px;
      box-shadow: 0 12px 32px rgba(0,0,0,0.45);
      cursor: grab;
      user-select: none;
      transition: box-shadow 0.2s ease, transform 0.15s ease;
      backdrop-filter: blur(4px);
    }
    .fb-note:active {
      cursor: grabbing;
      box-shadow: 0 20px 48px rgba(0,0,0,0.65);
      transform: scale(1.03) !important;
    }
    .fb-tape {
      position: absolute;
      top: -8px;
      left: 50%;
      transform: translateX(-50%);
      width: 52px;
      height: 16px;
      background: rgba(255,255,255,0.1);
      border: 1px solid rgba(255,255,255,0.15);
      border-radius: 2px;
    }
    .fb-note-from {
      font-size: 0.58rem;
      text-transform: uppercase;
      letter-spacing: 0.18em;
      color: rgba(255,255,255,0.35);
      margin-bottom: 10px;
      display: block;
    }
    .fb-note-title {
      font-size: 1rem;
      font-weight: 500;
      color: rgba(255,255,255,0.92);
      margin: 0 0 10px 0;
      letter-spacing: -0.02em;
      line-height: 1.25;
    }
    .fb-note-text {
      font-size: 0.8rem;
      color: rgba(255,255,255,0.5);
      margin: 0;
      line-height: 1.55;
    }
    @keyframes fbDropIn {
      0%  { opacity: 0; transform: translateY(-24px) scale(0.96); }
      100%{ opacity: 1; transform: translateY(0) scale(1); }
    }
    .fb-drop {
      animation: fbDropIn 0.55s cubic-bezier(0.16, 1, 0.3, 1) backwards;
    }
    @media (max-width: 640px) {
      .feedback-board { min-height: 900px; }
      .fb-note { width: 180px; }
    }