:root {
  --bg-primary: #0a0a0c;
  --bg-secondary: #141418;
  --bg-card: rgba(255, 255, 255, 0.05);
  --bg-card-hover: rgba(255, 255, 255, 0.08);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-glow: rgba(59, 130, 246, 0.3);
  --text-primary: #ffffff;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --brand-primary: #3b82f6;
  --brand-gradient: linear-gradient(135deg, #38bdf8 0%, #3b82f6 50%, #6366f1 100%);
  --accent-emerald: #10b981;
  --accent-rose: #f43f5e;
  --accent-amber: #f59e0b;
  --accent-purple: #8b5cf6;
  --radius-xl: 24px;
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-full: 9999px;
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-card: rgba(255, 255, 255, 0.85);
    --bg-card-hover: rgba(255, 255, 255, 1);
    --border-color: rgba(0, 0, 0, 0.06);
    --border-glow: rgba(59, 130, 246, 0.2);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
  }
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* Glass & Glow */
.glass {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border-color);
}

.gradient-text {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Navigation */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-bottom: 1px solid var(--border-color);
  background: rgba(10, 10, 12, 0.7);
}

@media (prefers-color-scheme: light) {
  nav {
    background: rgba(248, 250, 252, 0.8);
  }
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
}

.nav-logo {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

.nav-btn {
  padding: 8px 18px;
  border-radius: var(--radius-full);
  background: var(--text-primary);
  color: var(--bg-primary);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  transition: opacity 0.2s;
}

.nav-btn:hover {
  opacity: 0.9;
}

/* Hero Section */
.hero {
  max-width: 1100px;
  margin: 0 auto;
  padding: 80px 24px 60px;
  text-align: center;
  position: relative;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--brand-primary);
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.2);
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.2rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 36px;
  font-weight: 400;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--brand-gradient);
  color: #ffffff;
  padding: 14px 28px;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 1.05rem;
  text-decoration: none;
  box-shadow: 0 10px 30px rgba(59, 130, 246, 0.35);
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 36px rgba(59, 130, 246, 0.45);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 24px;
  border-radius: var(--radius-full);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-weight: 500;
  font-size: 1.05rem;
  text-decoration: none;
  transition: background 0.2s;
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
}

/* App Mockup Preview */
.mockup-container {
  max-width: 860px;
  margin: 50px auto 0;
  padding: 24px;
  border-radius: var(--radius-xl);
  position: relative;
  overflow: hidden;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.4);
}

.mockup-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.mockup-pill-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}

.mockup-pill {
  padding: 12px 16px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  font-weight: 500;
}

.pill-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

/* Feature Grid */
.features-section {
  max-width: 1100px;
  margin: 40px auto 80px;
  padding: 0 24px;
}

.section-head {
  text-align: center;
  margin-bottom: 48px;
}

.section-head h2 {
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-head p {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.feature-card {
  padding: 32px 28px;
  border-radius: var(--radius-xl);
  transition: transform 0.2s, border-color 0.2s;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
}

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
  background: rgba(59, 130, 246, 0.12);
  color: var(--brand-primary);
}

.feature-card h3 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.98rem;
  line-height: 1.6;
}

/* Content Pages (Privacy, Support) */
.page-container {
  max-width: 820px;
  margin: 40px auto 80px;
  padding: 0 24px;
  flex: 1;
}

.page-header {
  margin-bottom: 36px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 24px;
}

.page-header h1 {
  font-size: 2.6rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 10px;
}

.page-header .updated {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.article-content section {
  margin-bottom: 36px;
}

.article-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.article-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 20px 0 10px;
}

.article-content p, .article-content li {
  color: var(--text-secondary);
  font-size: 1.02rem;
  line-height: 1.75;
  margin-bottom: 12px;
}

.article-content ul {
  padding-left: 24px;
  margin-bottom: 16px;
}

.highlight-box {
  padding: 20px 24px;
  border-radius: var(--radius-lg);
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.25);
  margin: 24px 0;
}

.highlight-box.blue {
  background: rgba(59, 130, 246, 0.08);
  border: 1px solid rgba(59, 130, 246, 0.25);
}

.highlight-box h4 {
  font-size: 1.05rem;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.highlight-box p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 0;
}

/* FAQ Item */
.faq-item {
  padding: 20px 24px;
  border-radius: var(--radius-lg);
  margin-bottom: 16px;
}

.faq-item h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-top: 0;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.faq-item p {
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* Footer */
footer {
  border-top: 1px solid var(--border-color);
  padding: 40px 24px;
  background: var(--bg-secondary);
  margin-top: auto;
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
}

@media (min-width: 640px) {
  .footer-inner {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }
}

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

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}

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

.copyright {
  font-size: 0.85rem;
  color: var(--text-muted);
}