/* ccass_course_agentic.css
 * Stripe + blue theme for /ccass_course_agentic. Two-column course player
 * with a topic-list sidebar + video panel. Shares the .csa-* namespace
 * with the rest of the agentic surface; self-contained.
 */

:root {
  --csa-bg: #e7edf5;
  --csa-surface: #ffffff;
  --csa-surface-tint: #eff3f8;
  --csa-border: #cfd9e6;
  --csa-border-strong: #aebcce;
  --csa-text: #06203d;
  --csa-text-muted: #344662;
  --csa-text-subtle: #5b6b85;
  --csa-primary: #0a84ff;
  --csa-primary-strong: #0066d4;
  --csa-primary-dark: #1e40af;
  --csa-primary-soft: rgba(10, 132, 255, 0.10);
  --csa-cyan: #0891b2;
  --csa-accent-grad: linear-gradient(180deg, #2563eb 0%, #22d3ee 100%);
  --csa-radius: 12px;
  --csa-radius-sm: 8px;
  --csa-shadow-sm: 0 1px 2px rgba(6, 32, 61, 0.06), 0 1px 3px rgba(6, 32, 61, 0.08);
  --csa-shadow-md: 0 4px 14px rgba(6, 32, 61, 0.10), 0 2px 4px rgba(6, 32, 61, 0.06);
  --csa-shadow-lg: 0 18px 40px rgba(6, 32, 61, 0.14), 0 6px 12px rgba(6, 32, 61, 0.08);
  --csa-font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', 'Noto Sans TC', 'PingFang TC', 'Microsoft JhengHei', sans-serif;
  --csa-ease: cubic-bezier(0.22, 1, 0.36, 1);
}

html, body { background-color: var(--csa-bg); }
.csa-page *, .csa-page *::before, .csa-page *::after { box-sizing: border-box; }

.csa-page {
  background: var(--csa-bg);
  min-height: calc(100vh - 41px);
  padding: 36px 24px 56px;
  font-family: var(--csa-font);
  color: var(--csa-text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.csa-shell { max-width: 1200px; margin: 0 auto; }
.csa-shell--wide { max-width: 1320px; }

/* ---------- Hero ---------- */
.csa-hero {
  text-align: center;
  padding: 24px 0 28px;
}
.csa-hero--compact { padding: 12px 0 24px; }

.csa-eyebrow {
  display: inline-block;
  padding: 5px 12px;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--csa-primary);
  background: var(--csa-primary-soft);
  border: 1px solid rgba(10, 132, 255, 0.22);
  border-radius: 999px;
  margin-bottom: 16px;
}

.csa-hero__title {
  margin: 0 0 12px;
  font-size: clamp(24px, 3.2vw, 34px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--csa-text);
}
.csa-hero__title-tag {
  display: inline-block;
  margin-left: 12px;
  padding: 4px 10px;
  font-size: 13px;
  font-weight: 600;
  color: var(--csa-primary-strong);
  background: var(--csa-primary-soft);
  border: 1px solid rgba(10, 132, 255, 0.22);
  border-radius: 999px;
  vertical-align: middle;
  letter-spacing: 0;
}

.csa-hero__subtitle {
  margin: 0 auto;
  max-width: 820px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--csa-text-muted);
}

/* ---------- Two-column course layout ---------- */
.csa-cc-layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 24px;
  align-items: start;
}

@media (max-width: 980px) {
  .csa-cc-layout { grid-template-columns: 1fr; }
}

/* ---------- Sidebar topic list ---------- */
.csa-cc-menu {
  position: relative;
  background: var(--csa-surface);
  border: 1px solid var(--csa-border);
  border-radius: var(--csa-radius);
  box-shadow: var(--csa-shadow-sm);
  overflow: hidden;
}
.csa-cc-menu::before {
  content: '';
  position: absolute;
  top: 0; bottom: 0; left: 0;
  width: 3px;
  background: var(--csa-accent-grad);
}

.csa-cc-menu__head {
  padding: 16px 18px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--csa-text);
  background: var(--csa-surface-tint);
  border-bottom: 1px solid var(--csa-border);
  text-transform: uppercase;
}

.csa-cc-group + .csa-cc-group {
  border-top: 1px solid var(--csa-border);
}

.csa-cc-group__title {
  padding: 12px 18px 8px;
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--csa-primary-strong);
  text-transform: uppercase;
}

.csa-cc-topic {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 18px;
  font-size: 13.5px;
  line-height: 1.4;
  color: var(--csa-text-muted);
  cursor: pointer;
  border-left: 3px solid transparent;
  margin-left: -3px;     /* align with the accent bar at the very left */
  transition: background 140ms var(--csa-ease), color 140ms var(--csa-ease), border-color 140ms var(--csa-ease);
}
.csa-cc-topic:hover {
  background: var(--csa-primary-soft);
  color: var(--csa-text);
}
.csa-cc-topic.is-active {
  background: linear-gradient(90deg, rgba(10, 132, 255, 0.12) 0%, rgba(10, 132, 255, 0.04) 100%);
  color: var(--csa-text);
  font-weight: 600;
  border-left-color: var(--csa-primary);
}
.csa-cc-topic.is-active .csa-cc-topic__icon { color: var(--csa-primary); }

.csa-cc-topic__icon {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  font-size: 9px;
  color: var(--csa-text-subtle);
  background: var(--csa-surface-tint);
  border: 1px solid var(--csa-border);
  border-radius: 50%;
  line-height: 0;
}
.csa-cc-topic.is-active .csa-cc-topic__icon {
  background: var(--csa-primary);
  color: #fff;
  border-color: var(--csa-primary);
}

.csa-cc-topic__desc { flex: 1; min-width: 0; }
.csa-cc-topic__len {
  flex-shrink: 0;
  font-size: 12px;
  color: var(--csa-text-subtle);
  font-variant-numeric: tabular-nums;
}

/* ---------- Main video player ---------- */
.csa-cc-player {
  background: var(--csa-surface);
  border: 1px solid var(--csa-border);
  border-radius: var(--csa-radius);
  box-shadow: var(--csa-shadow-sm);
  padding: 28px 32px 32px;
}

.csa-cc-player__title {
  margin: 0 0 18px;
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--csa-text);
  line-height: 1.3;
  text-align: center;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--csa-border);
}

.csa-cc-player__frame {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: var(--csa-radius-sm);
  overflow: hidden;
  box-shadow: var(--csa-shadow-md);
}
.csa-cc-player__frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.csa-cc-player__cta {
  margin-top: 24px;
  text-align: center;
}

/* ---------- CTA buttons (shared) ---------- */
.csa-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 12px 26px;
  font-size: 15px;
  font-weight: 600;
  border-radius: 10px;
  text-decoration: none;
  transition: transform 140ms var(--csa-ease), box-shadow 160ms var(--csa-ease), background 160ms var(--csa-ease), color 160ms var(--csa-ease), border-color 160ms var(--csa-ease);
  letter-spacing: 0.01em;
  white-space: nowrap;
}
.csa-cta--lg { padding: 14px 32px; font-size: 16px; }
.csa-cta .csa-cta__arrow {
  display: inline-block;
  font-size: 18px;
  line-height: 0.8;
  transform: translateY(-1px);
  transition: transform 180ms var(--csa-ease);
}
.csa-cta:hover .csa-cta__arrow { transform: translate(3px, -1px); }
.csa-cta--primary {
  color: #fff;
  background: linear-gradient(180deg, #3b82f6 0%, var(--csa-primary-dark) 100%);
  border: 1px solid transparent;
  box-shadow:
    0 8px 22px rgba(37, 99, 235, 0.38),
    0 2px 6px rgba(37, 99, 235, 0.22),
    inset 0 1px 0 rgba(255, 255, 255, 0.25);
}
.csa-cta--primary:hover {
  color: #fff;
  text-decoration: none;
  transform: translateY(-1px);
  background: linear-gradient(180deg, #60a5fa 0%, var(--csa-primary-strong) 100%);
  box-shadow:
    0 12px 30px rgba(37, 99, 235, 0.45),
    0 3px 8px rgba(37, 99, 235, 0.28),
    inset 0 1px 0 rgba(255, 255, 255, 0.35);
}

.csa-cta__signin {
  margin-top: 12px;
  font-size: 13px;
  color: var(--csa-text-subtle);
}
.csa-cta__signin a {
  color: var(--csa-primary);
  font-weight: 600;
  text-decoration: none;
}
.csa-cta__signin a:hover { color: var(--csa-primary-strong); text-decoration: underline; }

.csa-cc-player__footnote {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px dashed var(--csa-border);
  text-align: center;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--csa-text-subtle);
}
.csa-cc-player__footnote a {
  color: var(--csa-primary);
  font-weight: 600;
  text-decoration: none;
}
.csa-cc-player__footnote a:hover { color: var(--csa-primary-strong); text-decoration: underline; }

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .csa-cc-menu { max-height: none; }
}
@media (max-width: 720px) {
  .csa-page { padding: 24px 14px 40px; }
  .csa-cc-player { padding: 22px 18px 24px; }
}