/* ============================================================
   PAGE 0018 — Dark Slate Premium Dark
   HTML Multi-Page — 暗黑高端风
   ============================================================ */

:root {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: #1e293b;
  --bg-elevated: #334155;
  --border-subtle: #1e293b;
  --border-default: #334155;
  --border-glow: #475569;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --cyan-400: #22d3ee;
  --cyan-500: #06b6d4;
  --cyan-600: #0891b2;
  --blue-400: #60a5fa;
  --blue-500: #3b82f6;
  --blue-600: #2563eb;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', -apple-system, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---------- Grid Pattern Background ---------- */
.bg-grid {
  background-image:
    linear-gradient(rgba(51,65,85,0.3) 1px, transparent 1px),
    linear-gradient(90deg, rgba(51,65,85,0.3) 1px, transparent 1px);
  background-size: 50px 50px;
}

/* ---------- Navbar ---------- */
.navbar-dark {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(15,23,42,0.88); backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-default);
  transition: all 0.3s ease;
}
.navbar-dark::after {
  content: ''; position: absolute; bottom: -1px; left: 0; right: 0;
  height: 1px; background: linear-gradient(90deg, transparent, var(--cyan-500), var(--blue-500), transparent);
  opacity: 0; transition: opacity 0.3s ease;
}
.navbar-dark.scrolled::after { opacity: 1; }
.nav-container {
  max-width: 1240px; margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.nav-logo-dark {
  font-size: 1.35rem; font-weight: 900; letter-spacing: -0.02em;
  text-decoration: none;
  background: linear-gradient(135deg, var(--cyan-400), var(--blue-400));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.nav-links-dark { display: flex; gap: 28px; list-style: none; align-items: center; }
.nav-links-dark a {
  text-decoration: none; color: var(--text-secondary);
  font-size: 0.9rem; font-weight: 500;
  transition: color 0.2s ease;
}
.nav-links-dark a:hover, .nav-links-dark a.active { color: var(--text-primary); }
.nav-btn-dark {
  background: linear-gradient(135deg, var(--cyan-500), var(--blue-500));
  color: #fff; border: none; padding: 9px 22px; border-radius: var(--radius-sm);
  font-size: 0.85rem; font-weight: 700; cursor: pointer;
  transition: all 0.3s ease; text-decoration: none; display: inline-block;
}
.nav-btn-dark:hover { transform: translateY(-1px); box-shadow: 0 4px 20px rgba(6,182,212,0.35); }
.nav-toggler-dark { display: none; background: none; border: none; color: var(--text-primary); font-size: 1.5rem; cursor: pointer; }
@media (max-width: 768px) {
  .nav-links-dark { display: none; }
  .nav-links-dark.open {
    display: flex; flex-direction: column;
    position: absolute; top: 68px; left: 0; right: 0;
    background: rgba(15,23,42,0.98); backdrop-filter: blur(20px);
    padding: 20px 24px; gap: 16px;
    border-bottom: 1px solid var(--border-default);
  }
  .nav-toggler-dark { display: block; }
}

/* ---------- Hero ---------- */
.hero-dark {
  padding: 150px 24px 100px; position: relative; overflow: hidden;
  background: var(--bg-primary);
}
.hero-dark::before {
  content: ''; position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(51,65,85,0.25) 1px, transparent 1px),
    linear-gradient(90deg, rgba(51,65,85,0.25) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at 50% 0%, black 40%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at 50% 0%, black 40%, transparent 70%);
}
.hero-dark-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 56px; align-items: center; position: relative; z-index: 1;
}
.hero-badge-dark {
  display: inline-block; padding: 5px 16px;
  background: rgba(6,182,212,0.12); color: var(--cyan-400);
  border: 1px solid rgba(6,182,212,0.25); border-radius: 999px;
  font-size: 0.78rem; font-weight: 600; margin-bottom: 20px;
}
.hero-title-dark {
  font-size: clamp(2.5rem, 5.5vw, 3.8rem);
  font-weight: 900; line-height: 1.12; letter-spacing: -0.03em;
  margin-bottom: 18px; color: var(--text-primary);
}
.hero-title-dark .gradient-text-dark {
  background: linear-gradient(135deg, var(--cyan-400), var(--blue-400), #818cf8);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: gradientShift 4s ease-in-out infinite;
  background-size: 200% 200%;
}
@keyframes gradientShift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}
.hero-desc-dark { font-size: 1.1rem; color: var(--text-secondary); line-height: 1.8; margin-bottom: 32px; }
.hero-img-dark {
  width: 100%; border-radius: var(--radius-lg);
  box-shadow: 0 0 60px rgba(6,182,212,0.18), 0 0 100px rgba(59,130,246,0.08);
  border: 1px solid var(--border-default);
}
.btn-cyan { display: inline-flex; align-items: center; gap: 8px; background: linear-gradient(135deg, var(--cyan-500), var(--blue-500)); color: #fff; padding: 14px 32px; border-radius: var(--radius-sm); font-weight: 700; font-size: 1rem; text-decoration: none; transition: all 0.3s; }
.btn-cyan:hover { transform: translateY(-2px); box-shadow: 0 8px 32px rgba(6,182,212,0.35); }
.btn-ghost-dark { display: inline-flex; align-items: center; gap: 8px; background: transparent; color: var(--text-primary); border: 1px solid var(--border-default); padding: 14px 32px; border-radius: var(--radius-sm); font-weight: 600; font-size: 1rem; text-decoration: none; transition: all 0.3s; }
.btn-ghost-dark:hover { border-color: var(--cyan-500); color: var(--cyan-400); }
@media (max-width: 768px) { .hero-dark-inner { grid-template-columns: 1fr; text-align: center; } .hero-img-dark { max-width: 340px; margin: 0 auto; } }

/* ---------- Section Common ---------- */
.section-dark { padding: 90px 24px; }
.section-container-dark { max-width: 1200px; margin: 0 auto; }
.section-label-dark { display: inline-block; font-size: 0.8rem; font-weight: 700; letter-spacing: 0.1em; color: var(--cyan-400); margin-bottom: 10px; text-transform: uppercase; }
.section-title-dark { font-size: clamp(1.75rem, 3.5vw, 2.5rem); font-weight: 800; letter-spacing: -0.02em; margin-bottom: 14px; color: var(--text-primary); }
.section-desc-dark { font-size: 1.05rem; color: var(--text-secondary); max-width: 560px; line-height: 1.7; }
.text-center { text-align: center; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* ---------- Features: Bordered Dark Cards with Neon Glow ---------- */
.features-grid-dark { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }
.feat-card-dark {
  padding: 32px 24px; background: var(--bg-secondary);
  border: 1px solid var(--border-default); border-radius: var(--radius-md);
  transition: all 0.35s ease; position: relative;
}
.feat-card-dark:hover {
  border-color: var(--cyan-500);
  box-shadow: 0 0 24px rgba(6,182,212,0.12), inset 0 0 24px rgba(6,182,212,0.02);
  transform: translateY(-4px);
}
.feat-icon-dark {
  font-size: 1.8rem; margin-bottom: 16px; display: inline-block;
  color: var(--cyan-400); transition: all 0.35s ease;
}
.feat-card-dark:hover .feat-icon-dark {
  text-shadow: 0 0 20px rgba(6,182,212,0.6), 0 0 40px rgba(6,182,212,0.3);
}
.feat-card-dark h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 8px; color: var(--text-primary); }
.feat-card-dark p { font-size: 0.925rem; color: var(--text-secondary); line-height: 1.7; }

/* ---------- Stats: Glass Cards with Gradient Top Borders ---------- */
.stats-grid-dark { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.stat-card-dark {
  background: rgba(30,41,59,0.7); backdrop-filter: blur(8px);
  border: 1px solid var(--border-default); border-radius: var(--radius-md);
  padding: 32px 20px; text-align: center; position: relative; overflow: hidden;
}
.stat-card-dark::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  border-radius: 3px 3px 0 0;
}
.stat-card-dark:nth-child(1)::before { background: linear-gradient(90deg, var(--cyan-400), var(--cyan-500)); }
.stat-card-dark:nth-child(2)::before { background: linear-gradient(90deg, var(--blue-400), var(--blue-500)); }
.stat-card-dark:nth-child(3)::before { background: linear-gradient(90deg, #a78bfa, #818cf8); }
.stat-card-dark:nth-child(4)::before { background: linear-gradient(90deg, #34d399, #10b981); }
.stat-number-dark { font-size: 2.5rem; font-weight: 900; letter-spacing: -0.03em; color: var(--text-primary); margin-bottom: 4px; }
.stat-label-dark { font-size: 0.9rem; color: var(--text-secondary); font-weight: 500; }
@media (max-width: 768px) { .stats-grid-dark { grid-template-columns: 1fr 1fr; } }
@media (max-width: 480px) { .stats-grid-dark { grid-template-columns: 1fr; } }

/* ---------- Testimonials: Horizontal Scroll Carousel ---------- */
.testimonials-scroll { overflow-x: auto; scroll-snap-type: x mandatory; -webkit-overflow-scrolling: touch; padding: 16px 0 28px; display: flex; gap: 20px; }
.testimonials-scroll::-webkit-scrollbar { height: 6px; }
.testimonials-scroll::-webkit-scrollbar-track { background: var(--bg-secondary); border-radius: 3px; }
.testimonials-scroll::-webkit-scrollbar-thumb { background: var(--border-glow); border-radius: 3px; }
.testimonial-card-dark {
  flex: 0 0 calc(33.333% - 14px); min-width: 280px;
  background: var(--bg-secondary); border: 1px solid var(--border-default);
  border-radius: var(--radius-md); padding: 28px 24px;
  scroll-snap-align: start; transition: border-color 0.3s;
}
.testimonial-card-dark:hover { border-color: var(--cyan-500); }
.tc-stars { color: #f59e0b; margin-bottom: 12px; font-size: 0.9rem; }
.tc-text { font-size: 0.95rem; color: var(--text-secondary); line-height: 1.7; margin-bottom: 18px; }
.tc-author { display: flex; align-items: center; gap: 12px; }
.tc-avatar { width: 44px; height: 44px; border-radius: 50%; object-fit: cover; border: 2px solid var(--border-default); }
.tc-name { font-weight: 700; font-size: 0.9rem; color: var(--text-primary); }
.tc-role { font-size: 0.8rem; color: var(--text-muted); }

/* ---------- FAQ: Vertical Tabs ---------- */
.faq-tabs-wrapper { display: flex; gap: 32px; max-width: 1000px; margin: 0 auto; }
.faq-tabs-nav { flex-shrink: 0; display: flex; flex-direction: column; gap: 6px; min-width: 200px; }
.faq-tab-btn {
  text-align: left; padding: 14px 18px; background: transparent; border: 1px solid transparent;
  border-radius: var(--radius-sm); color: var(--text-secondary); font-size: 0.925rem;
  font-weight: 500; cursor: pointer; transition: all 0.25s ease; font-family: inherit;
}
.faq-tab-btn:hover { background: var(--bg-secondary); color: var(--text-primary); }
.faq-tab-btn.active { background: var(--bg-secondary); border-color: var(--cyan-500); color: var(--cyan-400); font-weight: 600; }
.faq-tabs-content { flex: 1; }
.faq-tab-panel { display: none; padding: 20px 0; }
.faq-tab-panel.active { display: block; animation: fadeIn 0.35s ease; }
.faq-tab-panel h4 { font-size: 1.15rem; font-weight: 700; margin-bottom: 10px; color: var(--text-primary); }
.faq-tab-panel p { font-size: 0.95rem; color: var(--text-secondary); line-height: 1.8; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
@media (max-width: 768px) { .faq-tabs-wrapper { flex-direction: column; } .faq-tabs-nav { flex-direction: row; flex-wrap: wrap; min-width: 0; } }

/* ---------- CTA ---------- */
.cta-dark { padding: 80px 24px; }
.cta-card-dark {
  max-width: 720px; margin: 0 auto; padding: 60px 40px; text-align: center;
  background: linear-gradient(135deg, var(--cyan-600), var(--blue-600), #7c3aed);
  border-radius: var(--radius-lg); color: #fff; position: relative; overflow: hidden;
}
.cta-card-dark::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(circle at 30% 20%, rgba(255,255,255,0.08) 0%, transparent 50%);
}
.cta-card-dark > * { position: relative; z-index: 1; }
.cta-card-dark h2 { font-size: clamp(1.75rem, 3vw, 2.25rem); font-weight: 900; margin-bottom: 12px; }
.cta-card-dark p { font-size: 1rem; opacity: 0.9; margin-bottom: 28px; line-height: 1.7; }
.btn-white-dark { background: #fff; color: #0f172a; padding: 14px 36px; border-radius: var(--radius-sm); font-weight: 800; font-size: 1rem; text-decoration: none; display: inline-block; transition: all 0.3s; }
.btn-white-dark:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(0,0,0,0.2); }

/* ---------- Footer ---------- */
.footer-dark { background: var(--bg-secondary); border-top: 1px solid var(--border-default); padding: 48px 24px 28px; }
.footer-dark-grid { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px; }
.footer-dark-grid h5 { font-size: 0.9rem; font-weight: 700; margin-bottom: 16px; color: var(--text-primary); text-transform: uppercase; letter-spacing: 0.04em; }
.footer-dark-grid p, .footer-dark-grid a { color: var(--text-secondary); font-size: 0.85rem; text-decoration: none; line-height: 1.8; }
.footer-dark-grid a:hover { color: var(--cyan-400); }
.footer-dark-grid ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.footer-dark-bottom { max-width: 1200px; margin: 28px auto 0; padding-top: 20px; border-top: 1px solid var(--border-default); display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; }
.footer-dark-bottom span { color: var(--text-muted); font-size: 0.8rem; }
@media (max-width: 768px) { .footer-dark-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 480px) { .footer-dark-grid { grid-template-columns: 1fr; } }

/* ---------- Page Header (sub-pages) ---------- */
.page-header-dark { padding: 140px 24px 60px; text-align: center; border-bottom: 1px solid var(--border-default); background: var(--bg-primary); }
.page-header-dark h1 { font-size: clamp(2rem, 4vw, 3rem); font-weight: 900; background: linear-gradient(135deg, var(--cyan-400), var(--blue-400)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.page-header-dark p { color: var(--text-secondary); font-size: 1.05rem; margin-top: 10px; }

/* ---------- About Page ---------- */
.about-content-dark { padding: 80px 24px; max-width: 1000px; margin: 0 auto; display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.about-content-dark img { width: 100%; border-radius: var(--radius-lg); border: 1px solid var(--border-default); }
.about-content-dark h3 { font-size: 1.5rem; font-weight: 800; margin-bottom: 16px; color: var(--text-primary); }
.about-content-dark p { color: var(--text-secondary); line-height: 1.9; margin-bottom: 12px; font-size: 0.95rem; }
@media (max-width: 768px) { .about-content-dark { grid-template-columns: 1fr; } }

/* ---------- Contact Page ---------- */
.contact-grid-dark { padding: 60px 24px; max-width: 1000px; margin: 0 auto; display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
.contact-info-dark h3 { font-size: 1.5rem; font-weight: 700; margin-bottom: 20px; color: var(--text-primary); }
.contact-info-dark .ci-item { display: flex; gap: 14px; margin-bottom: 20px; align-items: flex-start; }
.contact-info-dark .ci-item i { color: var(--cyan-400); font-size: 1.1rem; margin-top: 4px; }
.contact-info-dark .ci-item strong { display: block; color: var(--text-primary); font-size: 0.9rem; margin-bottom: 2px; }
.contact-info-dark .ci-item span { color: var(--text-secondary); font-size: 0.85rem; }
.contact-form-dark { display: flex; flex-direction: column; gap: 16px; }
.contact-form-dark input, .contact-form-dark textarea, .contact-form-dark select {
  padding: 14px 18px; background: var(--bg-secondary); border: 1px solid var(--border-default);
  border-radius: var(--radius-sm); color: var(--text-primary); font-size: 0.95rem;
  font-family: inherit; outline: none; transition: border-color 0.2s;
}
.contact-form-dark input::placeholder, .contact-form-dark textarea::placeholder { color: var(--text-muted); }
.contact-form-dark input:focus, .contact-form-dark textarea:focus, .contact-form-dark select:focus { border-color: var(--cyan-500); }
.contact-form-dark textarea { min-height: 130px; resize: vertical; }
@media (max-width: 768px) { .contact-grid-dark { grid-template-columns: 1fr; } }

/* ---------- Particles/Ambient ---------- */
.ambient-glow-cyan {
  position: absolute; width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(6,182,212,0.08) 0%, transparent 70%);
  border-radius: 50%; pointer-events: none;
}