/* ── Help page styles ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:       #0f0f1a;
  --surface:  #1a1a2e;
  --border:   #2a2a4a;
  --text:     #e2e8f0;
  --muted:    #64748b;
  --accent:   #7c3aed;
  --accent2:  #06b6d4;
  --green:    #22c55e;
  --red:      #ef4444;
  --rank1:    #FFD700;
}

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

/* ── Navigation ──────────────────────────────────────────────── */
.help-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: transparent;
  transition: background .3s, box-shadow .3s;
}
.help-nav.scrolled {
  background: rgba(15, 15, 26, .95);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 var(--border);
}
.help-nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  gap: 32px;
}
.help-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex-shrink: 0;
}
.help-brand-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}
.help-brand-name {
  font-size: 18px;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.help-nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  margin-left: auto;
}
.help-nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color .2s;
  white-space: nowrap;
}
.help-nav-links a:hover { color: var(--text); }
.help-nav-cta {
  background: var(--accent) !important;
  color: #fff !important;
  padding: 7px 20px !important;
  border-radius: 8px;
  font-weight: 600 !important;
  transition: opacity .2s !important;
}
.help-nav-cta:hover { opacity: .85; }
.help-nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  margin-left: auto;
}
.help-nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
}

/* ── Hero ─────────────────────────────────────────────────────── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 120px 24px 80px;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 40% at 50% 0%, rgba(124, 58, 237, .15) 0%, transparent 70%),
    radial-gradient(ellipse 50% 40% at 80% 80%, rgba(6, 182, 212, .1) 0%, transparent 60%);
  pointer-events: none;
}
.hero-content {
  position: relative;
  max-width: 800px;
  text-align: center;
}
.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  border: 1px solid var(--accent);
  border-radius: 99px;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 24px;
  background: rgba(124, 58, 237, .08);
}
.hero h1 {
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -.02em;
}
.hero-gradient {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-desc {
  font-size: 17px;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 36px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}
.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 60px;
}
.hero-btn {
  padding: 14px 36px;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 700;
  text-decoration: none;
  transition: opacity .2s, transform .1s;
}
.hero-btn:hover { opacity: .85; }
.hero-btn:active { transform: scale(.97); }
.hero-btn-primary {
  background: linear-gradient(135deg, var(--accent), #9333ea);
  color: #fff;
  box-shadow: 0 4px 20px rgba(124, 58, 237, .3);
}
.hero-btn-outline {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}
.hero-btn-outline:hover { border-color: var(--accent); color: var(--accent); }
.hero-stats {
  display: flex;
  gap: 32px;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
}
.hero-stat { text-align: center; }
.hero-stat-num {
  display: block;
  font-size: 28px;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent2), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-stat-label {
  font-size: 13px;
  color: var(--muted);
}
.hero-stat-sep {
  width: 1px;
  height: 36px;
  background: var(--border);
}

/* ── Sections ─────────────────────────────────────────────────── */
.section {
  padding: 80px 24px;
}
.section-alt {
  background: var(--surface);
}
.section-inner {
  max-width: 1100px;
  margin: 0 auto;
}
.section-header {
  text-align: center;
  margin-bottom: 56px;
}
.section-tag {
  display: inline-block;
  padding: 4px 14px;
  border-radius: 99px;
  font-size: 12px;
  font-weight: 700;
  color: var(--accent);
  background: rgba(124, 58, 237, .12);
  border: 1px solid rgba(124, 58, 237, .2);
  margin-bottom: 14px;
  letter-spacing: .04em;
  text-transform: uppercase;
}
.section-header h2 {
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 800;
  margin-bottom: 12px;
}
.section-header p {
  font-size: 16px;
  color: var(--muted);
  max-width: 600px;
  margin: 0 auto;
}

/* ── Features Grid ────────────────────────────────────────────── */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  transition: border-color .3s, transform .2s;
}
.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}
.feature-highlight {
  grid-column: span 2;
  background: linear-gradient(135deg, rgba(124, 58, 237, .06), rgba(6, 182, 212, .04));
  border-color: rgba(124, 58, 237, .3);
}
.feature-icon {
  font-size: 32px;
  margin-bottom: 14px;
}
.feature-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}
.feature-card p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 16px;
}
.feature-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.feature-list li {
  padding: 4px 12px;
  background: rgba(255, 255, 255, .04);
  border: 1px solid rgba(255, 255, 255, .06);
  border-radius: 6px;
  font-size: 12px;
  color: var(--accent2);
  font-weight: 500;
}

/* ── Scenarios ────────────────────────────────────────────────── */
.scenarios-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.scenario-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  transition: border-color .3s;
}
.scenario-card:hover { border-color: var(--accent2); }
.scenario-icon {
  font-size: 36px;
  margin-bottom: 12px;
}
.scenario-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}
.scenario-card p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 16px;
}
.scenario-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.scenario-tags span {
  padding: 4px 12px;
  border-radius: 99px;
  font-size: 12px;
  font-weight: 600;
  background: rgba(124, 58, 237, .1);
  color: var(--accent);
  border: 1px solid rgba(124, 58, 237, .2);
}

/* ── Workflow ─────────────────────────────────────────────────── */
.workflow-steps {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  justify-content: center;
}
.workflow-step {
  flex: 1;
  max-width: 300px;
  text-align: center;
  padding: 24px;
}
.workflow-num {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  font-size: 22px;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 18px;
}
.workflow-step h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 10px;
}
.workflow-step p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
}
.workflow-arrow {
  font-size: 28px;
  color: var(--border);
  margin-top: 28px;
  flex-shrink: 0;
}

/* ── Data Grid ────────────────────────────────────────────────── */
.data-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.data-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px 20px;
  transition: border-color .3s;
}
.data-item:hover { border-color: var(--accent2); }
.data-icon {
  font-size: 28px;
  margin-bottom: 10px;
}
.data-item h4 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 8px;
}
.data-item p {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.6;
}

/* ── Advantages ───────────────────────────────────────────────── */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.advantage-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px 24px;
  transition: border-color .3s;
}
.advantage-item:hover { border-color: var(--accent); }
.advantage-num {
  font-size: 36px;
  font-weight: 900;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
  margin-bottom: 12px;
}
.advantage-item h4 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
}
.advantage-item p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
}

/* ── CTA / Contact ────────────────────────────────────────────── */
.section-cta {
  background: linear-gradient(180deg, var(--bg) 0%, var(--surface) 50%, var(--bg) 100%);
}
.cta-content {
  text-align: center;
}
.cta-content h2 {
  font-size: clamp(28px, 4vw, 38px);
  font-weight: 800;
  margin-bottom: 12px;
}
.cta-content > p {
  font-size: 17px;
  color: var(--muted);
  margin-bottom: 40px;
}
.contact-cards {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 36px;
}
.contact-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 36px;
  text-align: center;
  min-width: 260px;
  transition: border-color .3s, transform .2s;
}
.contact-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}
.contact-icon {
  font-size: 40px;
  margin-bottom: 12px;
}
.contact-card h4 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 12px;
}
.contact-id {
  font-size: 15px;
  color: var(--text);
  margin-bottom: 8px;
}
.contact-id strong {
  color: var(--accent2);
  font-size: 17px;
  letter-spacing: .02em;
}
.contact-hint {
  font-size: 12px;
  color: var(--muted);
}
.cta-note {
  max-width: 600px;
  margin: 0 auto;
}
.cta-note p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

/* ── Footer ───────────────────────────────────────────────────── */
.help-footer {
  border-top: 1px solid var(--border);
  padding: 32px 24px;
}
.help-footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.footer-brand img {
  -webkit-text-fill-color: initial;
}
.footer-links {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  justify-content: center;
}
.footer-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 13px;
  transition: color .2s;
}
.footer-links a:hover { color: var(--text); }
.footer-copy {
  font-size: 12px;
  color: var(--muted);
  opacity: .6;
}

/* ── AI Engine Grid ───────────────────────────────────────────── */
.ai-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.ai-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  transition: border-color .3s, transform .2s;
  position: relative;
  overflow: hidden;
}
.ai-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  opacity: 0;
  transition: opacity .3s;
}
.ai-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}
.ai-card:hover::before { opacity: 1; }
.ai-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}
.ai-label {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 3px 10px;
  border-radius: 6px;
  font-size: 11px;
  font-weight: 800;
  font-family: "SF Mono", "Fira Code", "Cascadia Code", monospace;
  letter-spacing: .06em;
  background: linear-gradient(135deg, rgba(124, 58, 237, .2), rgba(6, 182, 212, .15));
  color: var(--accent2);
  border: 1px solid rgba(124, 58, 237, .3);
  flex-shrink: 0;
}
.ai-card h4 {
  font-size: 17px;
  font-weight: 700;
}
.ai-card p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 16px;
}
.ai-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.ai-tags span {
  padding: 3px 10px;
  border-radius: 5px;
  font-size: 11px;
  font-weight: 600;
  font-family: "SF Mono", "Fira Code", "Cascadia Code", monospace;
  background: rgba(6, 182, 212, .08);
  color: var(--accent2);
  border: 1px solid rgba(6, 182, 212, .15);
}

/* ── Architecture Layers ─────────────────────────────────────── */
.arch-layers {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0;
}
.arch-layer {
  display: flex;
  gap: 20px;
  align-items: stretch;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: border-color .3s;
}
.arch-layer:hover { border-color: var(--accent); }
.arch-layer-label {
  writing-mode: vertical-lr;
  text-orientation: mixed;
  padding: 16px 12px;
  font-size: 11px;
  font-weight: 800;
  font-family: "SF Mono", "Fira Code", "Cascadia Code", monospace;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: #fff;
  background: linear-gradient(180deg, var(--accent), var(--accent2));
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  min-width: 44px;
}
.arch-layer-content {
  padding: 20px 24px;
  flex: 1;
}
.arch-layer-content h4 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 8px;
  font-family: "SF Mono", "Fira Code", "Cascadia Code", "PingFang SC", monospace;
}
.arch-layer-content p {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.6;
}
.arch-arrow {
  text-align: center;
  font-size: 18px;
  color: var(--accent);
  padding: 4px 0;
  opacity: .5;
}

/* ── Responsive ───────────────────────────────────────────────── */
@media (max-width: 900px) {
  .help-nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(15, 15, 26, .98);
    backdrop-filter: blur(10px);
    flex-direction: column;
    padding: 16px 24px;
    gap: 12px;
    border-bottom: 1px solid var(--border);
  }
  .help-nav-links.open { display: flex; }
  .help-nav-toggle { display: flex; }

  .features-grid {
    grid-template-columns: 1fr;
  }
  .feature-highlight {
    grid-column: span 1;
  }
  .scenarios-grid {
    grid-template-columns: 1fr;
  }
  .workflow-steps {
    flex-direction: column;
    align-items: center;
  }
  .workflow-arrow {
    transform: rotate(90deg);
    margin: -8px 0;
  }
  .data-grid {
    grid-template-columns: 1fr;
  }
  .ai-grid {
    grid-template-columns: 1fr;
  }
  .advantages-grid {
    grid-template-columns: 1fr;
  }
  .arch-layer-label {
    writing-mode: horizontal-tb;
    min-width: unset;
    padding: 10px 16px;
  }
  .arch-layer {
    flex-direction: column;
  }
  .contact-cards {
    flex-direction: column;
    align-items: center;
  }
}

@media (max-width: 600px) {
  .hero { padding: 100px 16px 60px; }
  .hero-desc { font-size: 15px; }
  .hero-stats { gap: 20px; }
  .hero-stat-sep { display: none; }
  .section { padding: 56px 16px; }
}