/* ─── Page Hero ──────────────────────────────────── */
.page-hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #0d1117 0%, #111827 50%, #0d0f1a 100%);
  border-bottom: 1px solid var(--border);
  padding: 72px 32px 64px;
}

.page-hero-inner {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
}

/* ─── Materials Main ─────────────────────────────── */
.materials-main {
  padding: 56px 0 80px;
}

/* ─── Lesson Block ───────────────────────────────── */
.lesson-block {
  margin-bottom: 72px;
  padding: 40px;
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 16px;
}

.lesson-header {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.lesson-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 72px;
  height: 36px;
  background: linear-gradient(135deg, rgba(79,142,247,0.2), rgba(168,85,247,0.2));
  border: 1px solid rgba(79,142,247,0.3);
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: #7fb3f8;
  padding: 0 14px;
  white-space: nowrap;
}

.lesson-badge.bonus {
  background: linear-gradient(135deg, rgba(245,158,11,0.2), rgba(244,63,94,0.2));
  border-color: rgba(245,158,11,0.3);
  color: var(--genai);
}

.lesson-meta h2 {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 4px;
}

.lesson-meta p {
  font-size: 13px;
  color: var(--gray);
}

/* ─── Speaker Section ────────────────────────────── */
.speaker-section {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 20px;
}

.speaker-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  flex-shrink: 0;
}

.speaker-avatar.james   { background: rgba(79,142,247,0.15); color: var(--basics); border: 1px solid rgba(79,142,247,0.3); }
.speaker-avatar.jiaqi   { background: rgba(34,197,94,0.15);  color: var(--ml);     border: 1px solid rgba(34,197,94,0.3); }
.speaker-avatar.lillian { background: rgba(245,158,11,0.15); color: var(--genai);  border: 1px solid rgba(245,158,11,0.3); }

.speaker-name {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 600;
  color: var(--white);
}

.speaker-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.speaker-topic {
  font-size: 12px;
  color: var(--gray);
}

/* ─── Media Grid ─────────────────────────────────── */
.media-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  margin-bottom: 12px;
}

/* ─── Media Card ─────────────────────────────────── */
.media-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: border-color var(--transition), transform var(--transition);
}

.media-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
}

/* Thumbnail area */
.media-thumb {
  position: relative;
  height: 140px;
  background: #0d1117;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  overflow: hidden;
}

.media-thumb:hover .thumb-overlay { opacity: 1; }

.thumb-icon {
  font-size: 36px;
  color: rgba(255,255,255,0.15);
  transition: color var(--transition);
  user-select: none;
}

.media-thumb:hover .thumb-icon { color: rgba(255,255,255,0.4); }

.thumb-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--transition);
  font-size: 13px;
  color: rgba(255,255,255,0.8);
  letter-spacing: 0.05em;
}

/* Audio thumb */
.audio-thumb {
  background: linear-gradient(135deg, #0d1117, #111827);
}

.audio-icon {
  font-size: 48px;
  color: rgba(6,182,212,0.3);
}

.audio-thumb:hover .audio-icon { color: rgba(6,182,212,0.6); }

/* PDF thumb */
.pdf-thumb {
  background: linear-gradient(135deg, #120d0d, #1a0e0e);
  cursor: pointer;
}

.pdf-icon {
  font-size: 22px;
  font-family: var(--font-mono);
  font-weight: 700;
  color: rgba(244,63,94,0.5);
  letter-spacing: 0.05em;
}

.pdf-thumb:hover .pdf-icon { color: rgba(244,63,94,0.9); }

/* Image thumb */
.image-thumb { cursor: pointer; height: 140px; }

/* RAR thumb */
.rar-thumb {
  background: linear-gradient(135deg, #0f1208, #141a08);
}

.rar-icon {
  font-size: 20px;
  font-family: var(--font-mono);
  font-weight: 700;
  color: rgba(163,230,53,0.5);
  letter-spacing: 0.05em;
}

/* ─── Media Info ─────────────────────────────────── */
.media-info {
  padding: 14px 16px 8px;
  flex: 1;
}

.media-type-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 4px;
  margin-bottom: 8px;
}

.media-type-badge.video { background: rgba(79,142,247,0.12); color: var(--basics); }
.media-type-badge.audio { background: rgba(6,182,212,0.12);  color: var(--nlp); }
.media-type-badge.pdf   { background: rgba(244,63,94,0.12);  color: var(--tools); }
.media-type-badge.image { background: rgba(34,197,94,0.12);  color: var(--ml); }
.media-type-badge.rar   { background: rgba(163,230,53,0.12); color: #a3e635; }

.media-info h3 {
  font-size: 14px;
  font-weight: 500;
  color: var(--white);
  line-height: 1.5;
  margin-bottom: 6px;
}

.media-meta {
  display: flex;
  gap: 10px;
}

.file-size {
  font-size: 11px;
  color: var(--gray);
  font-family: var(--font-mono);
}

/* ─── Media Actions ──────────────────────────────── */
.media-actions {
  display: flex;
  gap: 8px;
  padding: 12px 16px 14px;
  border-top: 1px solid var(--border);
}

.btn-play {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(255,255,255,0.07);
  border: 1px solid var(--border);
  color: var(--white);
  font-size: 12px;
  font-family: var(--font-main);
  padding: 7px 14px;
  border-radius: 6px;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  flex: 1;
  justify-content: center;
}

.btn-play:hover {
  background: rgba(255,255,255,0.12);
  border-color: var(--border-hover);
}

.btn-view { }

.btn-download {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(79,142,247,0.1);
  border: 1px solid rgba(79,142,247,0.25);
  color: var(--basics);
  font-size: 12px;
  font-family: var(--font-main);
  padding: 7px 14px;
  border-radius: 6px;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition), border-color var(--transition);
  flex: 1;
  justify-content: center;
}

.btn-download:hover {
  background: rgba(79,142,247,0.18);
  border-color: rgba(79,142,247,0.4);
}

/* ─── Player Dock ────────────────────────────────── */
.player-dock {
  display: none;
  position: sticky;
  top: 80px;
  z-index: 80;
  background: #0e1219;
  border: 1px solid rgba(79,142,247,0.3);
  border-radius: 12px;
  padding: 16px 20px;
  margin-bottom: 32px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.5);
}

.player-dock.active { display: block; }

.player-dock-info {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.player-dock-title {
  font-size: 14px;
  font-weight: 500;
  color: var(--white);
}

.player-dock-type {
  font-size: 11px;
  color: var(--gray);
  font-family: var(--font-mono);
}

.player-close {
  position: absolute;
  top: 14px;
  right: 16px;
  background: none;
  border: none;
  color: var(--gray);
  font-size: 14px;
  cursor: pointer;
  padding: 4px;
  transition: color var(--transition);
}

.player-close:hover { color: var(--white); }

.player-area video,
.player-area audio {
  width: 100%;
  border-radius: 8px;
  outline: none;
}

.player-area video {
  max-height: 360px;
  background: #000;
}

/* ─── Modals ─────────────────────────────────────── */
.modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 200;
  align-items: center;
  justify-content: center;
}

.modal.open { display: flex; }

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.8);
  backdrop-filter: blur(4px);
}

.modal-content {
  position: relative;
  z-index: 1;
  background: var(--bg-2);
  border: 1px solid var(--border-hover);
  border-radius: 16px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.pdf-modal-content {
  width: 90vw;
  max-width: 1000px;
  height: 88vh;
}

.image-modal-content {
  width: auto;
  max-width: 90vw;
  max-height: 90vh;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.modal-title {
  font-size: 14px;
  font-weight: 500;
  color: var(--white);
}

.modal-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.modal-download {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--basics);
  font-size: 13px;
  text-decoration: none;
  padding: 6px 12px;
  border: 1px solid rgba(79,142,247,0.3);
  border-radius: 6px;
  transition: background var(--transition);
}

.modal-download:hover { background: rgba(79,142,247,0.1); }

.modal-close {
  background: none;
  border: 1px solid var(--border);
  color: var(--gray);
  width: 30px;
  height: 30px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition), border-color var(--transition);
}

.modal-close:hover { color: var(--white); border-color: var(--border-hover); }

.modal-body {
  flex: 1;
  overflow: hidden;
}

.modal-body iframe {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}

.image-modal-body {
  padding: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ─── Responsive ─────────────────────────────────── */
@media (max-width: 768px) {
  .lesson-block { padding: 24px 16px; }
  .media-grid { grid-template-columns: 1fr; }
  .lesson-header { gap: 12px; }
  .lesson-meta h2 { font-size: 18px; }
  .pdf-modal-content { width: 95vw; height: 90vh; }
}