/* preview-v20.css — Ultra-Premium Glassmorphic Viewer & Student Desk Experience */

/* ── Section shell ───────────────────────────────────── */
.preview-section-v20 {
  background: #080f1d;
  padding: 60px 0 80px;
  color: #fff;
  position: relative;
  overflow: hidden;
}
.preview-section-v20::before {
  content: "";
  position: absolute;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 500px;
  background: radial-gradient(circle, rgba(23, 105, 232, 0.18) 0%, rgba(8, 15, 29, 0) 70%);
  pointer-events: none;
}
.preview-section-v20 .container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 20px;
  position: relative;
  z-index: 2;
}

.preview-v20-heading {
  text-align: center;
  margin-bottom: 36px;
}
.preview-v20-heading .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: 30px;
  background: rgba(23, 105, 232, 0.15);
  border: 1px solid rgba(23, 105, 232, 0.3);
  color: #60a5fa;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 14px;
}
.preview-v20-heading h2 {
  margin: 0 0 12px;
  font-size: clamp(26px, 4.5vw, 40px);
  font-weight: 800;
  color: #ffffff;
  line-height: 1.15;
  letter-spacing: -1px;
}
.preview-v20-heading p {
  max-width: 640px;
  margin: 0 auto;
  color: #94a3b8;
  font-size: 15px;
  line-height: 1.65;
}

/* ── Tab Switcher ────────────────────────────────────── */
.preview-v20-tabs {
  display: inline-flex;
  background: rgba(15, 23, 42, 0.8);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 5px;
  border-radius: 40px;
  margin-bottom: 28px;
  backdrop-filter: blur(12px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}
.preview-v20-tab {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 30px;
  border: 1px solid transparent;
  background: transparent;
  color: #94a3b8;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}
.preview-v20-tab:hover {
  color: #f8fafc;
}
.preview-v20-tab.is-active {
  background: linear-gradient(135deg, #1e40af 0%, #1d4ed8 100%);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(29, 78, 216, 0.4);
}
.preview-v20-tab-video {
  border: 1px solid rgba(245, 158, 11, 0.35);
  background: rgba(245, 158, 11, 0.08);
  color: #fbbf24;
}
.preview-v20-tab-video:hover {
  background: rgba(245, 158, 11, 0.18);
  color: #fef08a;
}
.preview-v20-tab-video.is-active {
  background: linear-gradient(135deg, #d97706 0%, #b45309 100%)!important;
  border-color: #f59e0b!important;
  color: #ffffff!important;
  box-shadow: 0 4px 25px rgba(245, 158, 11, 0.5)!important;
}
.preview-v20-tab-video .video-badge-pill {
  font-size: 10px;
  font-weight: 800;
  padding: 2px 7px;
  border-radius: 12px;
  background: #f59e0b;
  color: #000;
  letter-spacing: 0.05em;
}

/* ── Glassmorphic Frame ──────────────────────────────── */
.preview-v20-frame {
  background: rgba(15, 23, 42, 0.75);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 24px;
  backdrop-filter: blur(16px);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5), inset 0 1px 0 rgba(255, 255, 255, 0.15);
  overflow: hidden;
}

/* Toolbar */
.preview-v20-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  background: rgba(8, 15, 29, 0.6);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.preview-v20-toolbar-title strong {
  display: block;
  font-size: 14px;
  font-weight: 800;
  color: #f8fafc;
}
.preview-v20-toolbar-title small {
  display: block;
  font-size: 11px;
  color: #64748b;
  margin-top: 2px;
}

/* Canvas Area */
.preview-v20-content {
  position: relative;
  background: #020617;
}

.preview-v20-pane {
  display: none;
}
.preview-v20-pane.is-active {
  display: block;
}

/* Book Canvas */
.preview-v20-canvas {
  position: relative;
  aspect-ratio: 210 / 297;
  max-height: 680px;
  margin: 0 auto;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #000;
  box-shadow: 0 0 50px rgba(0,0,0,0.8);
}
.preview-v20-page {
  position: absolute;
  inset: 0;
  display: none;
}
.preview-v20-page.is-current {
  display: block;
  z-index: 2;
}
.preview-v20-page img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

/* Controls Bar */
.preview-v20-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 14px 24px;
  background: rgba(8, 15, 29, 0.8);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.preview-v20-nav-group {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  background: rgba(255, 255, 255, 0.04);
  padding: 4px 12px;
  border-radius: 40px;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.preview-v20-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border-radius: 30px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.06);
  color: #e2e8f0;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s ease;
}
.preview-v20-btn:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.3);
  color: #fff;
}
.preview-v20-btn:disabled {
  opacity: 0.3;
  cursor: default;
}

/* Floating Zoom Square (YouTube-style) */
.preview-v20-zoom-square {
  position: absolute;
  top: 16px;
  right: 16px;
  z-index: 10;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.25);
  background: rgba(8, 15, 29, 0.75);
  backdrop-filter: blur(8px);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.preview-v20-zoom-square:hover {
  background: rgba(37, 99, 235, 0.9);
  border-color: #60a5fa;
  transform: scale(1.08);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.5);
}

.preview-v20-page-count {
  font-size: 13px;
  font-weight: 700;
  color: #94a3b8;
  letter-spacing: 0.05em;
}

/* ── STUDENT DESK EXPERIENCE (Side-by-side Video + Live Book Notes) ── */
.student-desk-header {
  text-align: center;
  padding: 20px 24px 10px;
  background: rgba(8, 15, 29, 0.5);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
.student-desk-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 14px;
  border-radius: 20px;
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: #fbbf24;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.1em;
}
.desk-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #f59e0b;
  box-shadow: 0 0 8px #f59e0b;
  animation: pulseDot 1.6s infinite;
}
@keyframes pulseDot { 0%, 100% { opacity: 1; transform: scale(1); } 50% { opacity: 0.4; transform: scale(0.8); } }
.student-desk-header p {
  margin: 6px 0 0;
  font-size: 13px;
  color: #94a3b8;
}

.student-desk-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  padding: 24px;
  background: #020617;
  align-items: start;
}
@media (max-width: 880px) {
  .student-desk-grid { grid-template-columns: 1fr; }
}

.student-desk-video-col,
.student-desk-book-col {
  background: rgba(15, 23, 42, 0.8);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 18px;
  padding: 16px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.4);
}

.desk-card-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}
.desk-card-title strong {
  font-size: 14px;
  font-weight: 800;
  color: #f8fafc;
}
.desk-icon { font-size: 16px; margin-right: 6px; }
.desk-page-indicator {
  font-size: 11px;
  font-weight: 800;
  color: #60a5fa;
  background: rgba(37, 99, 235, 0.2);
  padding: 3px 10px;
  border-radius: 12px;
}

.student-desk-video-col video {
  width: 100%;
  aspect-ratio: 16/9;
  border-radius: 12px;
  outline: none;
  background: #000;
  box-shadow: 0 10px 30px rgba(0,0,0,0.6);
  display: block;
}

.desk-book-viewer {
  width: 100%;
  max-height: 420px;
  overflow-y: auto;
  border-radius: 12px;
  background: #ffffff;
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.1);
}
.desk-book-viewer img {
  width: 100%;
  display: block;
  object-fit: contain;
}

.desk-page-selector {
  display: flex;
  gap: 8px;
  margin-top: 14px;
  overflow-x: auto;
  padding-bottom: 4px;
}
.desk-select-btn {
  flex: 1;
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.05);
  color: #94a3b8;
  font-size: 11px;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s ease;
}
.desk-select-btn:hover {
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
}
.desk-select-btn.is-active {
  background: #2563eb;
  border-color: #3b82f6;
  color: #fff;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.4);
}

/* Thumbnails Strip */
.preview-v20-thumbs {
  display: flex;
  gap: 10px;
  padding: 16px 24px;
  background: rgba(2, 6, 23, 0.9);
  overflow-x: auto;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}
.preview-v20-thumb {
  flex: 0 0 auto;
  width: 56px;
  aspect-ratio: 210/297;
  border: 2px solid transparent;
  border-radius: 8px;
  overflow: hidden;
  background: none;
  padding: 0;
  cursor: pointer;
  opacity: 0.5;
  transition: all 0.2s ease;
}
.preview-v20-thumb:hover {
  opacity: 0.85;
}
.preview-v20-thumb.is-active {
  opacity: 1;
  border-color: #3b82f6;
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.5);
}
.preview-v20-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ── Lightbox modal ──────────────────────────────────── */
.preview-lightbox {
  position: fixed;
  inset: 0;
  z-index: 99999;
  background: rgba(8,20,42,.92);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  backdrop-filter: blur(8px);
  animation: lbFadeIn .2s ease;
}
.preview-lightbox[hidden] { display: none; }
@keyframes lbFadeIn { from { opacity: 0; } to { opacity: 1; } }

.preview-lightbox-inner {
  position: relative;
  max-width: 860px;
  width: 100%;
  background: #0f172a;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 40px 100px rgba(0,0,0,.8);
  display: flex;
  flex-direction: column;
  max-height: 92vh;
}
.preview-lightbox-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: #080f1d;
  color: #fff;
  gap: 12px;
  flex-shrink: 0;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.preview-lightbox-bar strong { font-size: 14px; color: #fff; }
.preview-lightbox-bar-actions { display: flex; align-items: center; gap: 8px; }
.preview-lightbox-bar button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.15);
  background: rgba(255,255,255,.08);
  color: #fff;
  font-size: 16px;
  cursor: pointer;
  transition: background .15s;
}
.preview-lightbox-bar button:hover { background: rgba(255,255,255,.2); }
.preview-lightbox-scroll {
  overflow-y: auto;
  flex: 1;
  padding: 20px;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  background: #020617;
}
.preview-lightbox-scroll img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
  box-shadow: 0 8px 30px rgba(0,0,0,.5);
  display: block;
}
.preview-lightbox-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  border-top: 1px solid rgba(255,255,255,0.1);
  background: #080f1d;
  flex-shrink: 0;
}
.preview-lightbox-nav button {
  padding: 8px 18px;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 8px;
  background: rgba(255,255,255,0.08);
  color: #f8fafc;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all .15s;
}
.preview-lightbox-nav button:hover:not(:disabled) { background: #2563eb; border-color: #3b82f6; color: #fff; }
.preview-lightbox-nav button:disabled { opacity: .3; cursor: default; }
.preview-lightbox-nav span { font-size: 12px; font-weight: 700; color: #94a3b8; }

/* ── Compare Grid (Student vs Teacher) ──────────────── */
.preview-v20-compare {
  margin-top: 48px;
}
.preview-v20-compare-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
@media (max-width: 640px) {
  .preview-v20-compare-grid { grid-template-columns: 1fr; }
}
.preview-v20-compare-card {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 18px;
  overflow: hidden;
  transition: transform 0.3s ease, border-color 0.3s ease;
}
.preview-v20-compare-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 255, 255, 0.2);
}
.preview-v20-compare-card-head {
  padding: 16px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(255, 255, 255, 0.03);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}
.preview-v20-compare-card-head strong { font-size: 15px; color: #f8fafc; }
.preview-v20-compare-card-head span {
  font-size: 10px;
  font-weight: 800;
  padding: 4px 10px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.preview-v20-compare-card.student span { background: rgba(37, 99, 235, 0.2); color: #60a5fa; }
.preview-v20-compare-card.teacher span { background: rgba(16, 185, 129, 0.2); color: #34d399; }
.preview-v20-compare-card img {
  width: 100%;
  display: block;
  cursor: pointer;
}

/* Consolidated Grid below Preview */
.streamlined-grid-v20 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 40px;
}
.streamlined-card-v20 {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.03);
}
.streamlined-card-v20 h3 { margin: 0 0 8px; font-size: 18px; font-weight: 800; color: #0f172a; }
.streamlined-card-v20 p { margin: 0; font-size: 14px; color: #64748b; line-height: 1.6; }