/* ============================================================
   拾文 SeaAI — Design System & Stylesheet
   Theme: High-end Minimal · Light · Professional
   ============================================================ */

/* ── Google Fonts Fallback (in case network is slow) ─────── */
@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;500;600;700&family=Inter:wght@300;400;500;600;700&display=swap');

/* ── CSS Design Tokens ──────────────────────────────────── */
:root {
  /* Colors */
  --c-bg:           #ffffff;
  --c-bg-soft:      #f8f9fb;
  --c-bg-muted:     #f2f4f7;
  --c-surface:      #ffffff;

  --c-primary:      #2563EB;
  --c-primary-light:#EFF6FF;
  --c-primary-mid:  #93C5FD;
  --c-primary-dark: #1D4ED8;

  --c-accent:       #7C3AED;
  --c-accent-light: #F5F3FF;

  --c-text:         #0F172A;
  --c-text-sub:     #475569;
  --c-text-muted:   #94A3B8;
  --c-border:       #E2E8F0;
  --c-border-soft:  #F1F5F9;

  --c-tag-train:    #DBEAFE;
  --c-tag-train-t:  #1D4ED8;
  --c-tag-geo:      #EDE9FE;
  --c-tag-geo-t:    #6D28D9;
  --c-tag-dev:      #DCFCE7;
  --c-tag-dev-t:    #166534;

  /* Typography */
  --font-serif: 'Noto Serif SC', 'Songti SC', 'STSong', serif;
  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Helvetica Neue', sans-serif;

  /* Spacing scale (4px base) */
  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 0.75rem;
  --sp-4: 1rem;
  --sp-5: 1.25rem;
  --sp-6: 1.5rem;
  --sp-8: 2rem;
  --sp-10: 2.5rem;
  --sp-12: 3rem;
  --sp-16: 4rem;
  --sp-20: 5rem;
  --sp-24: 6rem;

  /* Border radius */
  --r-sm: 6px;
  --r-md: 12px;
  --r-lg: 20px;
  --r-xl: 32px;
  --r-full: 9999px;

  /* Shadows */
  --shadow-xs: 0 1px 3px rgba(15,23,42,.06);
  --shadow-sm: 0 2px 8px rgba(15,23,42,.08);
  --shadow-md: 0 8px 24px rgba(15,23,42,.10);
  --shadow-lg: 0 20px 60px rgba(15,23,42,.12);
  --shadow-card: 0 4px 16px rgba(37,99,235,.08);

  /* Transitions */
  --ease-fast: 150ms ease;
  --ease-base: 280ms cubic-bezier(0.4,0,0.2,1);
  --ease-slow: 500ms cubic-bezier(0.4,0,0.2,1);

  /* Layout */
  --nav-h: 68px;
  --max-w: 1180px;
}

/* ── Reset & Base ───────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { background: none; border: none; cursor: pointer; font: inherit; }
ul, ol { list-style: none; }
input, select, textarea { font: inherit; }

/* ── Layout Container ───────────────────────────────────── */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: var(--sp-6);
}
@media (max-width: 640px) { .container { padding-inline: var(--sp-4); } }

/* ── Section Base ───────────────────────────────────────── */
.section { padding-block: var(--sp-24); }
@media (max-width: 768px) { .section { padding-block: var(--sp-16); } }

.section-header {
  text-align: center;
  max-width: 620px;
  margin-inline: auto;
  margin-bottom: var(--sp-12);
}
.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--c-primary);
  background: var(--c-primary-light);
  border: 1px solid var(--c-primary-mid);
  padding: var(--sp-1) var(--sp-3);
  border-radius: var(--r-full);
  margin-bottom: var(--sp-4);
}
.section-tag--light {
  color: #6366f1;
  background: #eef2ff;
  border-color: #c7d2fe;
}
.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  line-height: 1.3;
  color: var(--c-text);
  margin-bottom: var(--sp-4);
}
.section-desc {
  font-size: 1.0625rem;
  color: var(--c-text-sub);
  line-height: 1.8;
}

/* ── Text Gradient ──────────────────────────────────────── */
.text-gradient {
  background: linear-gradient(135deg, var(--c-primary) 0%, var(--c-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ── Buttons ────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 0.75rem 1.75rem;
  border-radius: var(--r-full);
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1;
  transition: all var(--ease-base);
  cursor: pointer;
  white-space: nowrap;
}
.btn:focus-visible {
  outline: 2px solid var(--c-primary);
  outline-offset: 3px;
}
.btn-primary {
  background: linear-gradient(135deg, var(--c-primary) 0%, var(--c-accent) 100%);
  color: #fff;
  box-shadow: 0 4px 20px rgba(37,99,235,.30);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(37,99,235,.38);
}
.btn-primary:active { transform: translateY(0); }

.btn-ghost {
  background: transparent;
  color: var(--c-primary);
  border: 1.5px solid var(--c-border);
}
.btn-ghost:hover {
  border-color: var(--c-primary);
  background: var(--c-primary-light);
  transform: translateY(-2px);
}
.btn-full { width: 100%; justify-content: center; }
.btn-icon { width: 18px; height: 18px; flex-shrink: 0; }

/* ============================================================
   NAVBAR
   ============================================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-h);
  background: rgba(255,255,255,0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--ease-base), box-shadow var(--ease-base);
}
.navbar.scrolled {
  border-bottom-color: var(--c-border);
  box-shadow: var(--shadow-sm);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}
.logo {
  display: flex;
  align-items: baseline;
  gap: var(--sp-2);
}
.logo-zh {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--c-text);
  letter-spacing: 0.05em;
}
.logo-en {
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--c-text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--sp-8);
}
.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--c-text-sub);
  transition: color var(--ease-fast);
  position: relative;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--c-primary);
  transition: width var(--ease-base);
}
.nav-links a:hover { color: var(--c-primary); }
.nav-links a:hover::after { width: 100%; }
.nav-cta {
  padding: 0.5rem 1.25rem;
  border-radius: var(--r-full);
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff !important;
  font-size: 0.875rem;
  box-shadow: 0 2px 12px rgba(37,99,235,.28);
  transition: transform var(--ease-base), box-shadow var(--ease-base) !important;
}
.nav-cta::after { display: none !important; }
.nav-cta:hover {
  transform: translateY(-1px) !important;
  box-shadow: 0 4px 18px rgba(37,99,235,.38) !important;
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  padding: 4px 0;
}
.hamburger span {
  display: block;
  height: 2px;
  background: var(--c-text);
  border-radius: 2px;
  transition: all var(--ease-base);
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 768px) {
  .hamburger { display: flex; }
  nav[aria-label="主导航"] {
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--c-border);
    padding: var(--sp-4) var(--sp-6);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-8px);
    transition: all var(--ease-base);
    box-shadow: var(--shadow-md);
  }
  nav[aria-label="主导航"].open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
  }
  .nav-links {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--sp-4);
  }
  .nav-links a { font-size: 1rem; }
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-h);
  background: #fafbff;
  overflow: hidden;
}

/* Soft gradient orbs in background */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 70% 30%, rgba(37,99,235,.07) 0%, transparent 70%),
    radial-gradient(ellipse 50% 40% at 20% 70%, rgba(124,58,237,.05) 0%, transparent 70%),
    radial-gradient(ellipse 80% 60% at 50% 50%, rgba(248,250,255,.8) 0%, transparent 80%);
  pointer-events: none;
}

/* Grid dot pattern */
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, rgba(37,99,235,.10) 1px, transparent 1px);
  background-size: 32px 32px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 50%, black 30%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 50%, black 30%, transparent 100%);
  pointer-events: none;
}

.hero-particles {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 0;
}
.particle {
  position: absolute;
  border-radius: 50%;
  animation: float-particle linear infinite;
  opacity: 0;
}

@keyframes float-particle {
  0%   { transform: translateY(100vh) scale(0); opacity: 0; }
  10%  { opacity: 1; }
  90%  { opacity: 0.6; }
  100% { transform: translateY(-20vh) scale(1.2); opacity: 0; }
}

.hero-content {
  position: relative;
  z-index: 1;
  padding-block: var(--sp-20);
  max-width: 900px;
  margin-inline: auto;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-badge {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  max-width: 480px;
  gap: var(--sp-2);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--c-primary);
  background: var(--c-primary-light);
  border: 1px solid rgba(37,99,235,.18);
  padding: var(--sp-1) var(--sp-3);
  border-radius: var(--r-full);
  margin-bottom: var(--sp-6);
  animation: fade-up 0.7s ease both;
}
.badge-dot {
  width: 6px;
  height: 6px;
  background: var(--c-primary);
  border-radius: 50%;
  animation: pulse-dot 1.8s ease-in-out infinite;
}
@keyframes pulse-dot {
  0%,100% { transform: scale(1); opacity: 1; }
  50%      { transform: scale(1.6); opacity: 0.5; }
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 7vw, 4.25rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--c-text);
  margin-bottom: var(--sp-6);
  animation: fade-up 0.7s 0.1s ease both;
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--c-text-sub);
  line-height: 1.85;
  margin-bottom: var(--sp-8);
  animation: fade-up 0.7s 0.2s ease both;
}
.hero-desc strong { color: var(--c-primary); font-weight: 600; }

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--sp-3);
  margin-bottom: var(--sp-12);
  animation: fade-up 0.7s 0.3s ease both;
}

.hero-stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-6);
  animation: fade-up 0.7s 0.4s ease both;
}
.stat-item {
  display: flex;
  flex-direction: column;
}
.stat-num {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  color: var(--c-text);
  line-height: 1;
}
.stat-unit {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--c-primary);
}
.stat-label {
  font-size: 0.75rem;
  color: var(--c-text-muted);
  margin-top: var(--sp-1);
}
.stat-divider {
  width: 1px;
  height: 40px;
  background: var(--c-border);
}

/* Scroll hint */
.hero-scroll-hint {
  position: absolute;
  bottom: var(--sp-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-2);
  opacity: 0.45;
  animation: fade-up 1s 1s ease both;
}
.hero-scroll-hint span {
  display: block;
  width: 1.5px;
  height: 48px;
  background: linear-gradient(to bottom, transparent, var(--c-primary));
  animation: scroll-line 1.8s ease-in-out infinite;
}
.hero-scroll-hint p {
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: var(--c-text-muted);
}
@keyframes scroll-line {
  0%,100% { transform: scaleY(0.3); transform-origin: top; }
  50%      { transform: scaleY(1); }
}

/* Animations */
@keyframes fade-up {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}

@media (max-width: 640px) {
  .hero-stats { gap: var(--sp-4); }
  .stat-num { font-size: 1.5rem; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; justify-content: center; }
}

/* ============================================================
   SERVICES
   ============================================================ */
.services { background: var(--c-bg-soft); }

.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-6);
}
@media (max-width: 900px)  { .services-grid { grid-template-columns: 1fr; max-width: 540px; margin-inline: auto; } }
@media (min-width: 640px) and (max-width: 900px) { .services-grid { grid-template-columns: repeat(2, 1fr); max-width: 100%; } }

.service-card {
  position: relative;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  padding: var(--sp-8);
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
  transition: transform var(--ease-base), box-shadow var(--ease-base), border-color var(--ease-base);
  cursor: default;
}
.service-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--c-primary-mid);
}
.service-card--featured {
  background: linear-gradient(160deg, #faf8ff 0%, #f0f9ff 100%);
  border-color: rgba(124,58,237,.2);
  box-shadow: var(--shadow-card);
}
.service-card--featured:hover {
  border-color: var(--c-accent);
  box-shadow: 0 24px 64px rgba(124,58,237,.15);
}
.featured-badge {
  position: absolute;
  top: var(--sp-5);
  right: var(--sp-5);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--c-accent);
  background: var(--c-accent-light);
  border: 1px solid rgba(124,58,237,.2);
  padding: 2px var(--sp-2);
  border-radius: var(--r-full);
  text-transform: uppercase;
}
.service-icon {
  width: 52px;
  height: 52px;
  background: var(--c-primary-light);
  border-radius: var(--r-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--c-primary);
  flex-shrink: 0;
  transition: background var(--ease-base), color var(--ease-base);
}
.service-icon svg { width: 26px; height: 26px; }
.service-card--featured .service-icon {
  background: var(--c-accent-light);
  color: var(--c-accent);
}
.service-card:hover .service-icon {
  background: var(--c-primary);
  color: #fff;
}
.service-card--featured:hover .service-icon {
  background: var(--c-accent);
  color: #fff;
}

.service-content { flex: 1; }
.service-name {
  font-family: var(--font-serif);
  font-size: 1.3125rem;
  font-weight: 700;
  margin-bottom: var(--sp-3);
  color: var(--c-text);
}
.service-desc {
  font-size: 0.9rem;
  color: var(--c-text-sub);
  line-height: 1.75;
  margin-bottom: var(--sp-4);
}
.service-features {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
}
.service-features li {
  font-size: 0.85rem;
  color: var(--c-text-sub);
  padding-left: var(--sp-5);
  position: relative;
}
.service-features li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--c-primary);
  font-weight: 700;
  font-size: 0.75rem;
}
.service-card--featured .service-features li::before { color: var(--c-accent); }

.service-link {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-1);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--c-primary);
  transition: gap var(--ease-fast), color var(--ease-fast);
  margin-top: auto;
}
.service-link:hover { gap: var(--sp-3); }
.service-card--featured .service-link { color: var(--c-accent); }

/* ============================================================
   ABOUT
   ============================================================ */
.about { background: var(--c-bg); }

.about-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-16);
  align-items: center;
}
@media (max-width: 768px) {
  .about-inner { grid-template-columns: 1fr; gap: var(--sp-10); }
  .about-visual { order: -1; }
}

/* Card stack illustration */
.about-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}
.about-card-stack {
  position: relative;
  width: 300px;
  height: 300px;
}
.about-card {
  position: absolute;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  padding: var(--sp-5) var(--sp-6);
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  box-shadow: var(--shadow-md);
  transition: transform var(--ease-slow);
  white-space: nowrap;
}
.about-card p { font-size: 0.9rem; font-weight: 600; color: var(--c-text); }
.about-card-icon { font-size: 1.25rem; color: var(--c-primary); }
.about-card-1 {
  top: 20px; left: 20px;
  background: linear-gradient(135deg, #eff6ff, #fff);
  animation: card-float 4s ease-in-out infinite;
}
.about-card-2 {
  top: 110px; left: 60px;
  background: linear-gradient(135deg, #f5f3ff, #fff);
  animation: card-float 4s 1.3s ease-in-out infinite;
}
.about-card-2 .about-card-icon { color: var(--c-accent); }
.about-card-3 {
  top: 200px; left: 40px;
  background: linear-gradient(135deg, #f0fdf4, #fff);
  animation: card-float 4s 2.6s ease-in-out infinite;
}
.about-card-3 .about-card-icon { color: #16a34a; }
@keyframes card-float {
  0%,100% { transform: translateY(0) rotate(-1deg); }
  50%      { transform: translateY(-8px) rotate(1deg); }
}

/* About text */
.about-text .section-title { text-align: left; margin-bottom: var(--sp-4); }
.about-desc {
  font-size: 0.9875rem;
  color: var(--c-text-sub);
  line-height: 1.85;
  margin-bottom: var(--sp-4);
}
.about-values {
  display: flex;
  flex-direction: column;
  gap: var(--sp-4);
  margin-top: var(--sp-6);
}
.value-item {
  display: flex;
  align-items: flex-start;
  gap: var(--sp-3);
  padding: var(--sp-4);
  border-radius: var(--r-md);
  background: var(--c-bg-soft);
  border: 1px solid var(--c-border-soft);
  transition: border-color var(--ease-base), box-shadow var(--ease-base);
}
.value-item:hover {
  border-color: var(--c-primary-mid);
  box-shadow: var(--shadow-sm);
}
.value-icon { font-size: 1.25rem; flex-shrink: 0; margin-top: 2px; }
.value-item strong { display: block; font-size: 0.9rem; font-weight: 600; color: var(--c-text); margin-bottom: 2px; }
.value-item p { font-size: 0.83rem; color: var(--c-text-sub); margin: 0; }

/* ============================================================
   CASES
   ============================================================ */
.cases { background: var(--c-bg-soft); }

.cases-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-6);
}
@media (max-width: 900px) { .cases-grid { grid-template-columns: 1fr; max-width: 480px; margin-inline: auto; } }
@media (min-width: 640px) and (max-width: 900px) { .cases-grid { grid-template-columns: repeat(2, 1fr); max-width: 100%; } }

.case-card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  padding: var(--sp-6) var(--sp-7);
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
  transition: transform var(--ease-base), box-shadow var(--ease-base);
}
.case-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.case-header { display: flex; align-items: center; justify-content: space-between; }
.case-tag {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  padding: 3px var(--sp-3);
  border-radius: var(--r-full);
  text-transform: uppercase;
}
.case-tag--training { background: var(--c-tag-train); color: var(--c-tag-train-t); }
.case-tag--geo      { background: var(--c-tag-geo);   color: var(--c-tag-geo-t); }
.case-tag--dev      { background: var(--c-tag-dev);   color: var(--c-tag-dev-t); }
.case-stars { color: #f59e0b; font-size: 0.875rem; letter-spacing: 2px; }
.case-quote {
  font-size: 0.9rem;
  color: var(--c-text-sub);
  line-height: 1.8;
  quotes: '"' '"' ''' ''';
  flex: 1;
}
.case-quote::before { content: open-quote; font-size: 2rem; color: var(--c-primary-mid); line-height: 0; vertical-align: -0.6em; margin-right: 4px; }
.case-author {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding-top: var(--sp-4);
  border-top: 1px solid var(--c-border-soft);
}
.case-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
  flex-shrink: 0;
}
.case-author strong { display: block; font-size: 0.875rem; font-weight: 600; color: var(--c-text); }
.case-author span   { font-size: 0.78rem; color: var(--c-text-muted); }

/* ============================================================
   FAQ
   ============================================================ */
.faq { background: var(--c-bg); }

.faq-list {
  max-width: 720px;
  margin-inline: auto;
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}
.faq-item {
  border: 1px solid var(--c-border);
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--c-surface);
  transition: border-color var(--ease-base), box-shadow var(--ease-base);
}
.faq-item:has(.faq-question[aria-expanded="true"]) {
  border-color: var(--c-primary-mid);
  box-shadow: var(--shadow-sm);
}
.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-5) var(--sp-6);
  gap: var(--sp-4);
  text-align: left;
  transition: background var(--ease-fast);
}
.faq-question:hover { background: var(--c-bg-soft); }
.faq-question span:first-child {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--c-text);
  line-height: 1.5;
}
.faq-icon {
  font-size: 1.25rem;
  color: var(--c-primary);
  font-weight: 300;
  flex-shrink: 0;
  transition: transform var(--ease-base);
  line-height: 1;
}
.faq-question[aria-expanded="true"] .faq-icon { transform: rotate(45deg); }
.faq-answer {
  padding: 0 var(--sp-6) var(--sp-5);
  animation: faq-in 0.25s ease;
}
.faq-answer p {
  font-size: 0.9rem;
  color: var(--c-text-sub);
  line-height: 1.85;
  padding-top: var(--sp-2);
  border-top: 1px solid var(--c-border-soft);
}
@keyframes faq-in {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ============================================================
   CONTACT
   ============================================================ */
.contact {
  background: linear-gradient(160deg, #f8faff 0%, #f4f0ff 100%);
  border-top: 1px solid var(--c-border);
}
.contact-inner {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: var(--sp-16);
  align-items: start;
}
.contact-inner--centered {
  grid-template-columns: 1fr;
  text-align: center;
  max-width: 600px;
  margin-inline: auto;
}
@media (max-width: 768px) { .contact-inner { grid-template-columns: 1fr; gap: var(--sp-10); } }

.contact-title { text-align: left; }
.contact-inner--centered .contact-title { text-align: center; }

.contact-desc {
  font-size: 0.9875rem;
  color: var(--c-text-sub);
  line-height: 1.85;
  margin-bottom: var(--sp-6);
}
.contact-info { display: flex; flex-direction: column; gap: var(--sp-3); }
.contact-inner--centered .contact-info { align-items: center; margin-top: var(--sp-4); }

.contact-info-item {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 0.9rem;
  color: var(--c-text-sub);
}
.contact-wechat {
  background: var(--c-surface);
  padding: var(--sp-4) var(--sp-8);
  border-radius: var(--r-full);
  box-shadow: var(--shadow-sm);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--c-text);
  border: 1px solid var(--c-border);
}
.contact-info-item a:hover { color: var(--c-primary); }

/* Form */
.contact-form {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  padding: var(--sp-8);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
}
.form-group { display: flex; flex-direction: column; gap: var(--sp-2); }
.form-group label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--c-text);
  letter-spacing: 0.02em;
}
.required-mark { color: var(--c-primary); }
.form-group input,
.form-group select,
.form-group textarea {
  padding: 0.6875rem var(--sp-4);
  border: 1.5px solid var(--c-border);
  border-radius: var(--r-sm);
  font-size: 0.9375rem;
  color: var(--c-text);
  background: var(--c-bg);
  transition: border-color var(--ease-fast), box-shadow var(--ease-fast);
}
.form-group input::placeholder,
.form-group textarea::placeholder { color: var(--c-text-muted); }
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,.1);
}
.form-group textarea { resize: vertical; min-height: 110px; }
.form-group select { appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='M5 7l5 5 5-5' stroke='%2394A3B8' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 12px center; background-size: 18px; padding-right: 2.5rem; cursor: pointer; }
.form-privacy { font-size: 0.75rem; color: var(--c-text-muted); text-align: center; }

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  background: var(--c-text);
  padding-block: var(--sp-10);
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--sp-6);
}
.footer-brand .logo-zh { color: #fff; font-size: 1.25rem; margin-bottom: var(--sp-1); }
.footer-brand p { font-size: 0.8rem; color: rgba(255,255,255,.45); margin-top: 4px; }
.footer-links { display: flex; gap: 0; flex-wrap: wrap; }
.footer-links a { flex: 1; text-align: center; min-width: 60px; }
.footer-links a {
  font-size: 0.85rem;
  color: rgba(255,255,255,.55);
  transition: color var(--ease-fast);
}
.footer-links a:hover { color: #fff; }
.footer-copy { font-size: 0.78rem; color: rgba(255,255,255,.35); }

@media (max-width: 640px) {
  .footer-inner { flex-direction: column; align-items: flex-start; }
  .footer-links { gap: var(--sp-4); }
}

/* ── Footer beian (ICP / 公安备案) ─────────────────────── */
.footer-beian {
  border-top: 1px solid rgba(255,255,255,.08);
  padding: var(--sp-5) var(--sp-6) var(--sp-2);
  margin-top: var(--sp-2);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-3);
  text-align: center;
  max-width: var(--max-w);
  margin-inline: auto;
  width: 100%;
}
.footer-copy {
  font-size: 0.78rem;
  color: rgba(255,255,255,.35);
}
.beian-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--sp-3);
}
.beian-item {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.75rem;
  color: rgba(255,255,255,.38);
  transition: color var(--ease-fast);
}
.beian-item:hover { color: rgba(255,255,255,.75); }
.beian-icon {
  width: 16px;
  height: 16px;
  object-fit: contain;
  opacity: 0.65;
  flex-shrink: 0;
}
.beian-divider {
  color: rgba(255,255,255,.2);
  font-size: 0.7rem;
  user-select: none;
}

/* ============================================================
   SCROLL-REVEAL ANIMATIONS
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }