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

:root {
  --primary: #2563eb;
  --primary-light: #3b82f6;
  --primary-dark: #1d4ed8;
  --primary-50: #eff6ff;
  --primary-100: #dbeafe;
  --accent: #06b6d4;
  --accent-light: #22d3ee;
  --surface: #ffffff;
  --surface-raised: #f8fafc;
  --surface-muted: #f1f5f9;
  --border: #e2e8f0;
  --border-light: #f1f5f9;
  --text: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --success: #10b981;
  --warning: #f59e0b;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.06), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.04);
  --shadow-xl: 0 20px 60px rgba(0,0,0,0.1), 0 8px 20px rgba(0,0,0,0.06);
}

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  font-family: 'Noto Sans TC', -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--text);
  background: var(--surface);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ─── NAV ─── */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-light);
  transition: box-shadow 0.3s ease;
}
nav.scrolled { box-shadow: var(--shadow-sm); }
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  padding: 0 32px; height: 72px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  display: flex; align-items: center; gap: 10px;
  text-decoration: none; color: var(--text);
  font-weight: 700; font-size: 18px;
}
.nav-logo-icon {
  width: 36px; height: 36px; border-radius: 10px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 900; font-size: 13px;
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: -0.5px;
}
.nav-links { display: flex; align-items: center; gap: 8px; }
.nav-links a {
  text-decoration: none; color: var(--text-secondary);
  padding: 8px 16px; border-radius: 8px;
  font-size: 14.5px; font-weight: 500;
  transition: all 0.2s ease;
}
.nav-links a:hover { color: var(--text); background: var(--surface-muted); }
.nav-cta {
  background: var(--primary) !important; color: #fff !important;
  padding: 9px 20px !important; border-radius: 10px !important;
  font-weight: 600 !important;
  transition: all 0.2s ease !important;
  box-shadow: 0 2px 8px rgba(37,99,235,0.25);
}
.nav-cta:hover {
  background: var(--primary-dark) !important;
  box-shadow: 0 4px 16px rgba(37,99,235,0.35) !important;
  transform: translateY(-1px);
}
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); margin: 5px 0; border-radius: 2px; transition: 0.3s; }

@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: fixed; top: 72px; left: 0; right: 0;
    background: rgba(255,255,255,0.98); backdrop-filter: blur(20px);
    flex-direction: column; padding: 16px 24px 24px;
    border-bottom: 1px solid var(--border);
    transform: translateY(-110%); opacity: 0;
    transition: all 0.3s ease; gap: 4px;
  }
  .nav-links.open { transform: translateY(0); opacity: 1; }
  .nav-links a { width: 100%; padding: 12px 16px; }
  .nav-cta { width: 100% !important; text-align: center; margin-top: 8px; }
}

/* ─── BUTTONS ─── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 32px; border-radius: 12px;
  font-size: 16px; font-weight: 600;
  text-decoration: none; cursor: pointer; border: none;
  transition: all 0.25s ease;
}
.btn-primary {
  background: var(--primary); color: #fff;
  box-shadow: 0 4px 16px rgba(37,99,235,0.3);
}
.btn-primary:hover {
  background: var(--primary-dark);
  box-shadow: 0 6px 24px rgba(37,99,235,0.4);
  transform: translateY(-2px);
}
.btn-ghost {
  background: var(--surface); color: var(--text);
  border: 1.5px solid var(--border);
}
.btn-ghost:hover {
  border-color: var(--primary-light); color: var(--primary);
  background: var(--primary-50);
}
.btn svg { width: 18px; height: 18px; }

/* ─── SECTION HEADER ─── */
.section-header { text-align: center; margin-bottom: 72px; }
.section-label {
  display: inline-block;
  font-size: 13px; font-weight: 700;
  color: var(--primary); text-transform: uppercase;
  letter-spacing: 0.08em; margin-bottom: 16px;
}
.section-header h2 {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 800; letter-spacing: -0.02em; margin-bottom: 16px;
}
.section-header p {
  font-size: 18px; color: var(--text-secondary);
  max-width: 560px; margin: 0 auto;
}

/* ─── FOOTER ─── */
footer {
  padding: 48px 32px;
  border-top: 1px solid var(--border);
  text-align: center;
}
.footer-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 16px;
}
.footer-brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 600; font-size: 15px; color: var(--text-secondary);
}
.footer-brand .nav-logo-icon { width: 28px; height: 28px; font-size: 10px; border-radius: 8px; }
.footer-links { display: flex; gap: 24px; }
.footer-links a {
  font-size: 14px; color: var(--text-muted);
  text-decoration: none; transition: color 0.2s;
}
.footer-links a:hover { color: var(--text); }
.footer-copy { font-size: 13px; color: var(--text-muted); width: 100%; margin-top: 16px; }

@media (max-width: 640px) {
  .footer-inner { justify-content: center; text-align: center; }
  .footer-links { justify-content: center; }
}

/* ─── ANIMATIONS ─── */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
.reveal {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ─── PRIVACY (shared) ─── */
.privacy {
  padding: 120px 32px;
  background: var(--surface-raised);
  border-top: 1px solid var(--border-light);
}
.privacy-inner { max-width: 800px; margin: 0 auto; }
.privacy-inner h2 {
  font-size: clamp(28px, 4vw, 36px);
  font-weight: 800; margin-bottom: 16px;
  text-align: center; letter-spacing: -0.02em;
}
.privacy-inner .privacy-updated {
  text-align: center; color: var(--text-muted);
  font-size: 14px; margin-bottom: 48px;
}
.privacy-section { margin-bottom: 40px; }
.privacy-section h3 {
  font-size: 20px; font-weight: 700; margin-bottom: 16px; color: var(--text);
  padding-bottom: 10px; border-bottom: 2px solid var(--primary-100);
}
.privacy-section h4 {
  font-size: 16px; font-weight: 600; margin: 20px 0 10px; color: var(--text);
}
.privacy-section p {
  font-size: 15px; color: var(--text-secondary);
  margin-bottom: 12px; line-height: 1.85;
}
.privacy-section ul { list-style: none; padding: 0; }
.privacy-section ul li {
  font-size: 15px; color: var(--text-secondary);
  padding: 6px 0 6px 24px; position: relative; line-height: 1.8;
}
.privacy-section ul li::before {
  content: ''; position: absolute; left: 8px; top: 14px;
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--primary-light);
}
.privacy-section code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px; background: var(--surface-muted);
  padding: 2px 8px; border-radius: 4px;
  border: 1px solid var(--border); word-break: break-all;
}
.privacy-section a {
  color: var(--primary); text-decoration: none;
  border-bottom: 1px solid var(--primary-100); transition: border-color 0.2s;
}
.privacy-section a:hover { border-color: var(--primary); }

@media (max-width: 640px) {
  .privacy { padding: 80px 20px; }
}