/* ==========================================================================
   AI 智囊团圆桌 · Official Download Website Stylesheet
   Editorial Warm Ivory (Light) & Neutral Obsidian Charcoal (Dark)
   ========================================================================== */

:root {
  color-scheme: light dark;

  /* Light defaults (Fallback base) */
  --bg-canvas: #f9f8f5;
  --bg-surface: #ffffff;
  --bg-subtle: #f2efe8;
  --bg-elevated: #fcfbf9;
  --bg-header: rgba(249, 248, 245, 0.86);

  --text-primary: #181816;
  --text-secondary: #53524d;
  --text-muted: #7c7a72;

  --border-hairline: #e5e2da;
  --border-strong: #d1cdc2;

  --accent: #0d6e66;
  --accent-hover: #095650;
  --accent-contrast: #ffffff;
  --accent-soft: rgba(13, 110, 102, 0.09);
  --accent-border: rgba(13, 110, 102, 0.28);

  --counter: #c2410c;
  --counter-soft: rgba(194, 65, 12, 0.09);
  --counter-border: rgba(194, 65, 12, 0.28);

  --shadow-card: 0 1px 2px rgba(20, 20, 18, 0.04), 0 12px 32px -12px rgba(20, 20, 18, 0.07);
  --shadow-frame: 0 2px 6px rgba(20, 20, 18, 0.05), 0 24px 56px -16px rgba(20, 20, 18, 0.12);
  --backdrop-tint: rgba(18, 18, 16, 0.52);

  --scroll-thumb: #c8c4b8;
  --scroll-track: transparent;

  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 22px;

  accent-color: var(--accent);
  scrollbar-width: thin;
  scrollbar-color: var(--scroll-thumb) var(--scroll-track);
}

/* Fallback for browsers without light-dark() support */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-canvas: #141413;
    --bg-surface: #1d1d1b;
    --bg-subtle: #252522;
    --bg-elevated: #22221f;
    --bg-header: rgba(20, 20, 19, 0.86);

    --text-primary: #f2f1ed;
    --text-secondary: #aba9a0;
    --text-muted: #7b7970;

    --border-hairline: #2d2c28;
    --border-strong: #3e3d38;

    --accent: #14b8a6;
    --accent-hover: #2dd4bf;
    --accent-contrast: #082724;
    --accent-soft: rgba(20, 184, 166, 0.13);
    --accent-border: rgba(20, 184, 166, 0.34);

    --counter: #fb923c;
    --counter-soft: rgba(251, 146, 60, 0.13);
    --counter-border: rgba(251, 146, 60, 0.34);

    --shadow-card: 0 1px 2px rgba(0, 0, 0, 0.35), 0 16px 36px -14px rgba(0, 0, 0, 0.5);
    --shadow-frame: 0 2px 8px rgba(0, 0, 0, 0.45), 0 28px 64px -16px rgba(0, 0, 0, 0.68);
    --backdrop-tint: rgba(0, 0, 0, 0.68);

    --scroll-thumb: #45443e;
  }
}

/* Progressive enhancement with native CSS light-dark() */
@supports (color: light-dark(white, black)) {
  :root {
    --bg-canvas: light-dark(#f9f8f5, #141413);
    --bg-surface: light-dark(#ffffff, #1d1d1b);
    --bg-subtle: light-dark(#f2efe8, #252522);
    --bg-elevated: light-dark(#fcfbf9, #22221f);
    --bg-header: light-dark(rgba(249, 248, 245, 0.86), rgba(20, 20, 19, 0.86));

    --text-primary: light-dark(#181816, #f2f1ed);
    --text-secondary: light-dark(#53524d, #aba9a0);
    --text-muted: light-dark(#7c7a72, #7b7970);

    --border-hairline: light-dark(#e5e2da, #2d2c28);
    --border-strong: light-dark(#d1cdc2, #3e3d38);

    --accent: light-dark(#0d6e66, #14b8a6);
    --accent-hover: light-dark(#095650, #2dd4bf);
    --accent-contrast: light-dark(#ffffff, #082724);
    --accent-soft: light-dark(rgba(13, 110, 102, 0.09), rgba(20, 184, 166, 0.13));
    --accent-border: light-dark(rgba(13, 110, 102, 0.28), rgba(20, 184, 166, 0.34));

    --counter: light-dark(#c2410c, #fb923c);
    --counter-soft: light-dark(rgba(194, 65, 12, 0.09), rgba(251, 146, 60, 0.13));
    --counter-border: light-dark(rgba(194, 65, 12, 0.28), rgba(251, 146, 60, 0.34));

    --shadow-card: light-dark(
      0 1px 2px rgba(20, 20, 18, 0.04),
      0 1px 2px rgba(0, 0, 0, 0.35)
    );
    --shadow-frame: light-dark(
      0 24px 56px -16px rgba(20, 20, 18, 0.12),
      0 28px 64px -16px rgba(0, 0, 0, 0.68)
    );
    --backdrop-tint: light-dark(rgba(18, 18, 16, 0.52), rgba(0, 0, 0, 0.68));
    --scroll-thumb: light-dark(#c8c4b8, #45443e);
  }
}

/* Explicit user theme override — re-declares inherited tokens & accent-color */
:root[data-theme="light"] {
  color-scheme: only light;
  --bg-canvas: #f9f8f5;
  --bg-surface: #ffffff;
  --bg-subtle: #f2efe8;
  --bg-elevated: #fcfbf9;
  --bg-header: rgba(249, 248, 245, 0.86);
  --text-primary: #181816;
  --text-secondary: #53524d;
  --text-muted: #7c7a72;
  --border-hairline: #e5e2da;
  --border-strong: #d1cdc2;
  --accent: #0d6e66;
  --accent-hover: #095650;
  --accent-contrast: #ffffff;
  --accent-soft: rgba(13, 110, 102, 0.09);
  --accent-border: rgba(13, 110, 102, 0.28);
  --counter: #c2410c;
  --counter-soft: rgba(194, 65, 12, 0.09);
  --counter-border: rgba(194, 65, 12, 0.28);
  --backdrop-tint: rgba(18, 18, 16, 0.52);
  --scroll-thumb: #c8c4b8;
  accent-color: var(--accent);
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg-canvas: #141413;
  --bg-surface: #1d1d1b;
  --bg-subtle: #252522;
  --bg-elevated: #22221f;
  --bg-header: rgba(20, 20, 19, 0.86);
  --text-primary: #f2f1ed;
  --text-secondary: #aba9a0;
  --text-muted: #7b7970;
  --border-hairline: #2d2c28;
  --border-strong: #3e3d38;
  --accent: #14b8a6;
  --accent-hover: #2dd4bf;
  --accent-contrast: #082724;
  --accent-soft: rgba(20, 184, 166, 0.13);
  --accent-border: rgba(20, 184, 166, 0.34);
  --counter: #fb923c;
  --counter-soft: rgba(251, 146, 60, 0.13);
  --counter-border: rgba(251, 146, 60, 0.34);
  --backdrop-tint: rgba(0, 0, 0, 0.68);
  --scroll-thumb: #45443e;
  accent-color: var(--accent);
}

/* ==========================================================================
   Reset & Base Typography
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img,
video,
svg {
  display: block;
  max-width: 100%;
}

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-hairline);
  padding: 0.12em 0.42em;
  border-radius: 5px;
}

a {
  color: inherit;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.container {
  width: min(1140px, 100% - 40px);
  margin-inline: auto;
}

/* ==========================================================================
   Top Navigation Header
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--bg-header);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-hairline);
}

.header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.brand-icon {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.14);
}

.brand-name {
  font-size: 1rem;
}

.version-pill {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-muted);
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-hairline);
  padding: 2px 7px;
  border-radius: 999px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
}

.site-nav a {
  text-decoration: none;
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color 160ms ease;
}

.site-nav a:hover {
  color: var(--text-primary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Theme Icon Toggle Visibility */
.icon-moon {
  display: none;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .icon-sun {
    display: none;
  }
  :root:not([data-theme="light"]) .icon-moon {
    display: block;
  }
}

:root[data-theme="dark"] .icon-sun {
  display: none;
}

:root[data-theme="dark"] .icon-moon {
  display: block;
}

/* ==========================================================================
   Buttons & Interactive Controls
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border-radius: 10px;
  font-family: inherit;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background-color 160ms ease, border-color 160ms ease, transform 140ms ease;
  white-space: nowrap;
}

.btn:active {
  transform: translateY(1px);
}

.btn-sm {
  min-height: 36px;
  padding: 0 14px;
  font-size: 0.86rem;
}

.btn-lg {
  min-height: 50px;
  padding: 0 22px;
  font-size: 0.96rem;
}

.btn-block {
  width: 100%;
  justify-content: space-between;
}

.btn-primary {
  background-color: var(--accent);
  color: var(--accent-contrast);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
}

.btn-outline {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border-color: var(--border-strong);
}

.btn-outline:hover {
  background-color: var(--bg-subtle);
}

.btn-ghost {
  background-color: transparent;
  color: var(--text-primary);
  border-color: var(--border-hairline);
}

.btn-ghost:hover {
  background-color: var(--bg-subtle);
}

.btn-sub {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  opacity: 0.84;
  padding-left: 8px;
  border-left: 1px solid currentColor;
}

.icon-btn {
  width: 36px;
  height: 36px;
  display: inline-grid;
  place-items: center;
  border-radius: 9px;
  border: 1px solid var(--border-hairline);
  background-color: var(--bg-surface);
  color: var(--text-secondary);
  cursor: pointer;
  transition: background-color 150ms ease, color 150ms ease;
}

.icon-btn:hover {
  background-color: var(--bg-subtle);
  color: var(--text-primary);
}

.text-link-btn {
  background: none;
  border: none;
  padding: 0;
  font: inherit;
  color: var(--text-secondary);
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.text-link-btn:hover {
  color: var(--text-primary);
}

.inline-link {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}

.inline-link:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  padding: 72px 0 44px;
}

.eyebrow-row {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 13px;
  border-radius: 999px;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  font-size: 0.82rem;
  color: var(--text-secondary);
  margin-bottom: 22px;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.hero-title {
  margin: 0 0 20px;
  font-size: clamp(2.1rem, 4.3vw, 3.45rem);
  line-height: 1.16;
  letter-spacing: -0.028em;
  font-weight: 720;
  max-width: 19em;
}

.hero-lead {
  margin: 0 0 32px;
  max-width: 68ch;
  font-size: clamp(1.02rem, 1.35vw, 1.14rem);
  color: var(--text-secondary);
  line-height: 1.72;
}

.hero-lead strong {
  color: var(--text-primary);
  font-weight: 620;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
}

.hero-meta-strip {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.hero-meta-strip li {
  position: relative;
}

.hero-meta-strip li + li::before {
  content: "·";
  margin-right: 22px;
  color: var(--border-strong);
}

/* ==========================================================================
   Product Demo Showcase Frame
   ========================================================================== */

.demo-section {
  padding: 8px 0 76px;
}

.demo-frame {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-xl);
  padding: 20px;
  box-shadow: var(--shadow-frame);
}

.demo-topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.section-kicker {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}

.demo-heading {
  margin: 0;
  font-size: 1.18rem;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.chapter-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.chapter-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-hairline);
  background-color: var(--bg-canvas);
  color: var(--text-secondary);
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 150ms ease, border-color 150ms ease, color 150ms ease;
}

.chapter-btn:hover {
  border-color: var(--border-strong);
  color: var(--text-primary);
}

.chapter-btn.is-active {
  background-color: var(--accent-soft);
  border-color: var(--accent-border);
  color: var(--accent);
  font-weight: 600;
}

.chapter-num {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  opacity: 0.8;
}

.video-viewport {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-hairline);
  background-color: var(--bg-subtle);
  aspect-ratio: 16 / 9;
}

.video-viewport video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ==========================================================================
   Section Scaffolding & Three-Stage Dialectic Ledger
   ========================================================================== */

.section-block {
  padding: 80px 0;
  border-top: 1px solid var(--border-hairline);
}

.section-tinted {
  background-color: var(--bg-elevated);
}

.section-header {
  max-width: 68ch;
  margin-bottom: 44px;
}

.section-title {
  margin: 0 0 14px;
  font-size: clamp(1.6rem, 2.7vw, 2.2rem);
  line-height: 1.24;
  letter-spacing: -0.02em;
  font-weight: 700;
}

.section-desc {
  margin: 0;
  color: var(--text-secondary);
  font-size: 1.02rem;
}

.dialectic-ledger {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.ledger-step {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 28px 26px;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-card);
}

.ledger-step.is-counter {
  border-top: 3px solid var(--counter);
}

.ledger-step.is-master {
  border-top: 3px solid var(--accent);
}

.step-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 16px;
}

.step-tag {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: 6px;
  background-color: var(--bg-subtle);
  color: var(--text-secondary);
}

.step-tag.counter-tag {
  background-color: var(--counter-soft);
  color: var(--counter);
}

.step-tag.master-tag {
  background-color: var(--accent-soft);
  color: var(--accent);
}

.step-role {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.ledger-step h3 {
  margin: 0 0 12px;
  font-size: 1.22rem;
  letter-spacing: -0.01em;
}

.ledger-step p {
  margin: 0 0 22px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  flex: 1;
}

.step-footnote {
  padding-top: 14px;
  border-top: 1px dashed var(--border-hairline);
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Asymmetric Split: Engineering Capabilities + 9-Seat Roster
   ========================================================================== */

.split-editorial {
  display: grid;
  grid-template-columns: 1.08fr 0.92fr;
  gap: 48px;
  align-items: start;
}

.feature-definitions {
  margin: 32px 0 0;
}

.def-item {
  padding: 18px 0;
  border-top: 1px solid var(--border-hairline);
}

.def-item dt {
  font-weight: 650;
  font-size: 1.02rem;
  margin-bottom: 6px;
}

.def-item dd {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.93rem;
}

.roster-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 26px;
  box-shadow: var(--shadow-card);
}

.roster-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-hairline);
  margin-bottom: 8px;
}

.roster-kicker {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.roster-title {
  margin: 0;
  font-size: 1.12rem;
}

.roster-badge {
  font-size: 0.76rem;
  padding: 3px 9px;
  border-radius: 999px;
  background-color: var(--bg-subtle);
  color: var(--text-secondary);
  border: 1px solid var(--border-hairline);
}

.roster-row {
  display: grid;
  grid-template-columns: 10px 108px 1fr;
  align-items: baseline;
  gap: 10px;
  padding: 10px 8px;
  border-bottom: 1px solid var(--border-hairline);
  font-size: 0.88rem;
}

.roster-row:last-child {
  border-bottom: none;
}

.roster-row.is-highlight {
  background-color: var(--accent-soft);
  border-radius: 8px;
  border-bottom-color: transparent;
  margin-block: 3px;
}

.seat-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  transform: translateY(-1px);
}

.seat-dot.is-teal {
  background-color: var(--accent);
}

.seat-dot.is-counter {
  background-color: var(--counter);
}

.seat-dot.is-master {
  background-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.seat-name {
  font-weight: 640;
  font-family: var(--font-mono);
  font-size: 0.84rem;
}

.seat-spec {
  color: var(--text-secondary);
}

/* ==========================================================================
   Download & Lifetime Pro Offer Cards
   ========================================================================== */

.offer-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  align-items: stretch;
}

.offer-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-xl);
  padding: 32px 30px;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-card);
}

.offer-card.is-featured {
  border-color: var(--accent-border);
  box-shadow: 0 0 0 1px var(--accent-border), var(--shadow-card);
}

.offer-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-hairline);
  margin-bottom: 18px;
}

.plan-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.plan-label.is-accent {
  color: var(--accent);
}

.offer-title {
  margin: 0;
  font-size: 1.28rem;
  letter-spacing: -0.015em;
}

.price-box {
  text-align: right;
  flex-shrink: 0;
}

.price-main {
  display: block;
  font-size: 1.95rem;
  font-weight: 740;
  line-height: 1.05;
  letter-spacing: -0.03em;
}

.price-note {
  display: block;
  font-size: 0.76rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.offer-summary {
  margin: 0 0 18px;
  color: var(--text-secondary);
  font-size: 0.94rem;
}

.offer-checklist {
  list-style: none;
  padding: 0;
  margin: 0 0 26px;
  display: grid;
  gap: 10px;
  font-size: 0.92rem;
  flex: 1;
}

.offer-checklist li {
  position: relative;
  padding-left: 22px;
  color: var(--text-secondary);
}

.offer-checklist li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent);
  font-weight: 700;
}

.offer-checklist strong {
  color: var(--text-primary);
}

.offer-cta-stack {
  display: grid;
  gap: 10px;
  margin-bottom: 18px;
}

.checksum-box {
  background-color: var(--bg-canvas);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-md);
  padding: 12px 14px;
}

.checksum-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.checksum-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  flex-shrink: 0;
}

.checksum-code {
  font-size: 0.74rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
  background: transparent;
  border: none;
  padding: 0;
  color: var(--text-secondary);
}

.copy-chip {
  flex-shrink: 0;
  padding: 3px 9px;
  border-radius: 6px;
  border: 1px solid var(--border-strong);
  background-color: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.74rem;
  font-weight: 500;
  cursor: pointer;
}

.copy-chip:hover {
  background-color: var(--bg-subtle);
}

.install-hint {
  margin: 8px 0 0;
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.55;
}

.install-cmd-row {
  margin-top: 8px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
}

.install-cmd-row code {
  font-size: 0.74rem;
  background: transparent;
  border: none;
  padding: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.gatekeeper-steps {
  border-top: none;
  padding-top: 0;
}

.cli-fallback {
  margin-top: 14px;
  font-size: 0.84rem;
  color: var(--text-secondary);
}

.cli-fallback summary {
  cursor: pointer;
  color: var(--text-muted);
  user-select: none;
}

.cli-fallback summary:hover {
  color: var(--text-primary);
}

.cli-fallback-body {
  margin-top: 10px;
  padding: 12px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-canvas);
  border: 1px solid var(--border-hairline);
}

.cli-fallback-body p {
  margin: 0 0 8px;
  font-size: 0.81rem;
}

.code-snippet-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.activation-mini-steps {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 10px;
  padding: 12px 14px;
  border-radius: var(--radius-md);
  background-color: var(--accent-soft);
  font-size: 0.81rem;
  color: var(--text-secondary);
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  border-top: 1px solid var(--border-hairline);
  padding: 34px 0 48px;
  color: var(--text-muted);
  font-size: 0.86rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 14px;
}

.footer-brand strong {
  color: var(--text-primary);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 20px;
}

.footer-links a {
  text-decoration: none;
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: var(--text-primary);
}

/* ==========================================================================
   Modal Dialog (Top Layer Animations + Scroll Containment)
   ========================================================================== */

.purchase-dialog {
  width: min(620px, calc(100vw - 28px));
  max-height: min(88dvh, 760px);
  padding: 0;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-xl);
  background-color: var(--bg-surface);
  color: var(--text-primary);
  box-shadow: var(--shadow-frame);
  overflow: auto;

  /* Exit / closed base state for discrete top-layer transitions */
  opacity: 0;
  transform: translateY(10px) scale(0.985);
  transition-property: opacity, transform, display, overlay;
  transition-duration: 200ms;
  transition-timing-function: cubic-bezier(0.2, 0, 0, 1);
  transition-behavior: allow-discrete;
}

.purchase-dialog:modal {
  overscroll-behavior: contain;
}

.purchase-dialog::backdrop {
  background-color: rgba(18, 18, 16, 0);
  backdrop-filter: blur(3px);
  -webkit-backdrop-filter: blur(3px);
  overflow: hidden;
  overscroll-behavior: contain;
  transition-property: background-color, display, overlay;
  transition-duration: 200ms;
  transition-timing-function: ease;
  transition-behavior: allow-discrete;
}

:is(.purchase-dialog[open]):where(:not([data-closing])) {
  opacity: 1;
  transform: translateY(0) scale(1);

  @starting-style {
    opacity: 0;
    transform: translateY(10px) scale(0.985);
  }

  &::backdrop {
    background-color: var(--backdrop-tint);

    @starting-style {
      background-color: rgba(18, 18, 16, 0);
    }
  }
}

@media (prefers-reduced-motion: reduce) {
  .purchase-dialog,
  .purchase-dialog::backdrop {
    transition: none;
  }
}

.dialog-shell {
  padding: 26px 28px 28px;
}

.dialog-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-hairline);
}

.dialog-title {
  margin: 0;
  font-size: 1.24rem;
  letter-spacing: -0.015em;
}

.dialog-body {
  padding-top: 18px;
  display: grid;
  gap: 18px;
}

.dialog-price-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 18px;
  border-radius: var(--radius-md);
  background-color: var(--accent-soft);
  border: 1px solid var(--accent-border);
}

.dialog-price-banner p {
  margin: 4px 0 0;
  font-size: 0.84rem;
  color: var(--text-secondary);
}

.dialog-price-tag {
  font-size: 1.75rem;
  font-weight: 750;
  color: var(--accent);
  flex-shrink: 0;
}

.channel-cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.channel-card {
  padding: 18px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-hairline);
  background-color: var(--bg-canvas);
  display: flex;
  flex-direction: column;
}

.channel-head {
  margin-bottom: 8px;
}

.channel-head h3 {
  margin: 0 0 4px;
  font-size: 0.98rem;
}

.channel-tag {
  display: inline-block;
  font-size: 0.74rem;
  color: var(--accent);
  font-weight: 600;
}

.channel-card p {
  margin: 0 0 16px;
  font-size: 0.84rem;
  color: var(--text-secondary);
  flex: 1;
}

.merchant-notice {
  padding: 16px 18px;
  border-radius: var(--radius-md);
  background-color: var(--accent-soft);
  border: 1px solid var(--accent-border);
  font-size: 0.86rem;
}

.merchant-notice strong {
  color: var(--accent);
}

.merchant-notice > strong {
  display: block;
  margin-bottom: 6px;
  font-size: 0.92rem;
}

.merchant-notice p {
  margin: 0;
  color: var(--text-secondary);
  line-height: 1.65;
}

.notice-actions {
  margin-top: 12px;
}

.activation-guide {
  padding-top: 6px;
  border-top: 1px solid var(--border-hairline);
}

.activation-guide h3 {
  margin: 10px 0 8px;
  font-size: 0.95rem;
}

.activation-guide ol {
  margin: 0;
  padding-left: 20px;
  display: grid;
  gap: 6px;
  font-size: 0.86rem;
  color: var(--text-secondary);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 960px) {
  .dialectic-ledger {
    grid-template-columns: 1fr;
  }

  .split-editorial {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .offer-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .site-nav {
    display: none;
  }

  .desktop-br {
    display: none;
  }

  .hero-section {
    padding: 48px 0 32px;
  }

  .hero-cta-group .btn-lg {
    width: 100%;
    justify-content: space-between;
  }

  .hero-meta-strip li + li::before {
    display: none;
  }

  .demo-frame {
    padding: 14px;
  }

  .channel-cards {
    grid-template-columns: 1fr;
  }

  .roster-row {
    grid-template-columns: 10px 1fr;
  }

  .seat-spec {
    grid-column: 2;
  }
}

/* Multi-Platform Downloads Grid (v2.1.0) */
.hero-multi-downloads {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 24px;
}

.hero-download-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 12px;
}

@media (max-width: 860px) {
  .hero-download-grid {
    grid-template-columns: 1fr;
  }
}

.hero-dl-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 14px;
  border: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  color: var(--text-primary);
  text-decoration: none;
  transition: all 0.2s ease;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.04);
}

.hero-dl-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(16, 185, 129, 0.12);
}

.hero-dl-card.recommended-platform {
  border-color: var(--accent);
  background: var(--bg-tint);
}

.dl-card-icon {
  font-size: 24px;
  flex-shrink: 0;
}

.dl-card-info {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-width: 0;
}

.dl-card-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-primary);
}

.dl-card-meta {
  font-size: 11.5px;
  color: var(--text-secondary);
}

.dl-card-btn {
  font-size: 12px;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--accent);
  color: var(--accent-fg);
  flex-shrink: 0;
}

.hero-sub-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

.offer-multi-dl-stack {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 16px 0;
}

.offer-dl-btn {
  font-size: 13px !important;
  padding: 12px 14px !important;
  text-align: center;
  text-decoration: none;
}

.checksum-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.checksum-item {
  background: var(--bg-subtle);
  border-radius: 8px;
  padding: 8px 10px;
  border: 1px solid var(--border-subtle);
}

.cs-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}

.cs-tag {
  font-size: 11.5px;
  font-weight: 700;
  color: var(--text-secondary);
}


/* ==========================================================================
   AI智囊奇葩说 · Swiss Tech Editorial & Dual-Video Layout Enhancements
   ========================================================================== */

.hero-container {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 48px;
  align-items: center;
}

@media (max-width: 1080px) {
  .hero-container {
    grid-template-columns: 1fr;
    gap: 36px;
  }
}

.hero-content {
  display: flex;
  flex-direction: column;
}

.hero-terminal-row {
  margin: 14px 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.terminal-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

.terminal-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #0F172A;
  color: #F8FAFC;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.1);
  font-family: var(--font-mono);
  font-size: 12.5px;
  gap: 12px;
  overflow-x: auto;
}

.terminal-box code {
  color: #38BDF8;
  white-space: nowrap;
}

/* Swiss Tech Hero Video Card */
.swiss-video-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 45px -15px rgba(15, 23, 42, 0.12), 0 0 0 1px rgba(15, 23, 42, 0.04);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.swiss-video-card:hover {
  box-shadow: 0 28px 60px -15px rgba(15, 23, 42, 0.18), 0 0 0 1px var(--accent);
}

.video-card-header {
  padding: 12px 18px;
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border-hairline);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.live-pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #10B981;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.25);
  animation: pulseGlow 2s infinite ease-in-out;
}

@keyframes pulseGlow {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.3); opacity: 0.7; }
}

.video-card-title {
  font-size: 13.5px;
  font-weight: 700;
  color: var(--text-primary);
}

.voice-tag {
  font-size: 12px;
  font-weight: 600;
  color: #0284C7;
  background: rgba(2, 132, 199, 0.1);
  padding: 3px 8px;
  border-radius: 6px;
}

.hero-video-viewport video {
  width: 100%;
  height: auto;
  display: block;
  background: #020617;
}

.video-card-footer {
  padding: 10px 18px;
  background: var(--bg-surface);
  font-size: 12.5px;
  color: var(--text-muted);
  border-top: 1px solid var(--border-hairline);
}

/* Contrast Section */
.contrast-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  margin-top: 36px;
}

@media (max-width: 840px) {
  .contrast-grid {
    grid-template-columns: 1fr;
  }
}

.contrast-card {
  padding: 32px 30px;
  border-radius: var(--radius-lg);
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
}

.card-flaw {
  border-top: 4px solid #EF4444;
}

.card-superior {
  border-top: 4px solid #0D9488;
  background: linear-gradient(180deg, var(--bg-surface) 0%, rgba(13, 148, 136, 0.03) 100%);
}

.contrast-badge {
  display: inline-flex;
  align-items: center;
  font-size: 12.5px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 6px;
  margin-bottom: 14px;
  width: fit-content;
}

.badge-flaw {
  background: #FEF2F2;
  color: #DC2626;
  border: 1px solid #FCA5A5;
}

.badge-superior {
  background: #F0FDFA;
  color: #0D9488;
  border: 1px solid #99F6E4;
}

.contrast-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 18px;
}

.contrast-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.contrast-list li {
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--text-secondary);
}

.contrast-list li strong {
  color: var(--text-primary);
}

/* Triple Export Section */
.export-cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 36px;
}

@media (max-width: 900px) {
  .export-cards-grid {
    grid-template-columns: 1fr;
  }
}

.export-card {
  padding: 30px 24px;
  border-radius: var(--radius-lg);
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  position: relative;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.export-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}

.export-card.card-featured {
  border-color: #0284C7;
  box-shadow: 0 16px 36px -12px rgba(2, 132, 199, 0.15);
}

.export-icon {
  font-size: 36px;
  margin-bottom: 12px;
}

.export-ext {
  position: absolute;
  top: 24px;
  right: 24px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--text-muted);
  background: var(--bg-subtle);
  padding: 3px 8px;
  border-radius: 6px;
}

.export-card h3 {
  font-size: 19px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.export-card p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-secondary);
  margin-bottom: 18px;
}

.export-feats {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 13px;
  color: var(--text-muted);
  border-top: 1px solid var(--border-hairline);
  padding-top: 14px;
}

.tag-live {
  font-size: 12.5px;
  font-weight: 700;
  color: #10B981;
}

.demo-sub {
  font-size: 13px;
  color: var(--text-muted);
}

/* ==========================================================================
   AI智囊奇葩说 · Distinctive Brand Typography & Hero Polish
   ========================================================================== */

.brand-title-special {
  display: inline-flex;
  align-items: center;
  font-size: 26px;
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1;
  gap: 3px;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
}

.brand-badge-ai {
  background: linear-gradient(135deg, #0284C7 0%, #2563EB 100%);
  color: #FFFFFF !important;
  padding: 3px 8px;
  border-radius: 7px;
  font-size: 17px;
  font-weight: 900;
  margin-right: 4px;
  box-shadow: 0 2px 8px rgba(2, 132, 199, 0.35);
  display: inline-block;
  line-height: 1;
}

.brand-text-council {
  color: var(--text-primary);
  font-weight: 800;
}

.brand-text-qipa {
  background: linear-gradient(135deg, #F43F5E 0%, #EA580C 50%, #EAB308 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 900;
  filter: drop-shadow(0 2px 10px rgba(234, 88, 12, 0.25));
  letter-spacing: -0.01em;
  margin-left: 1px;
}