/* ==========================================================================
   Kim Long Đường & Next Tutor - Base Styling
   Color Palette:
   - Primary Herbal Deep Green: #064E3B (Forest Green)
   - Secondary Jade Green: #047857
   - Accent Warm Gold: #B45309 (WCAG contrast compliant on light bg)
   - Soft Gold Highlight: #F59E0B
   - Background Parchment: #FBF9F5
   - Surface Pure White: #FFFFFF
   - Border Subtle: #E7E5E4
   - Text Slate Heading: #1C1917
   - Text Slate Body: #44403C
   ========================================================================== */

:root {
  --primary-deep: #064E3B;
  --primary-jade: #047857;
  --accent-gold: #B45309;
  --accent-gold-light: #F59E0B;
  --bg-parchment: #FBF9F5;
  --surface: #FFFFFF;
  --border: #E7E5E4;
  --text-heading: #1C1917;
  --text-body: #44403C;
  --text-muted: #78716C;
  --font-serif: "Times New Roman", Times, Georgia, "Noto Serif", serif;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --max-w: 960px;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-parchment);
  color: var(--text-body);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-heading);
}

.brand-title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-deep);
  line-height: 1.2;
}

.brand-subtitle {
  font-size: 0.8rem;
  color: var(--accent-gold);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 20px;
  list-style: none;
}

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

.nav-links a:hover, .nav-links a.active {
  color: var(--primary-jade);
}

.lang-switch {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  font-size: 0.85rem;
  margin-left: 8px;
}

.lang-switch a {
  padding: 4px 10px;
  text-decoration: none;
  color: var(--text-muted);
  background: var(--surface);
  font-weight: 600;
}

.lang-switch a.active {
  background: var(--primary-deep);
  color: #FFFFFF;
}

/* Hero Section */
.hero {
  padding: 60px 0 40px;
  text-align: center;
  background: linear-gradient(180deg, #F5F1E8 0%, var(--bg-parchment) 100%);
  border-bottom: 1px solid var(--border);
}

.hero-badge {
  display: inline-block;
  padding: 6px 14px;
  background: rgba(180, 83, 9, 0.1);
  color: var(--accent-gold);
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 16px;
  border: 1px solid rgba(180, 83, 9, 0.2);
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: 2.35rem;
  color: var(--primary-deep);
  line-height: 1.3;
  margin-bottom: 16px;
}

.hero p.lead {
  font-size: 1.15rem;
  color: var(--text-body);
  max-width: 760px;
  margin: 0 auto 24px;
}

/* Card & Section */
.section {
  padding: 48px 0;
}

.card {
  background: var(--surface);
  border-radius: 12px;
  border: 1px solid var(--border);
  padding: 32px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
  margin-bottom: 28px;
}

.card-title {
  font-family: var(--font-serif);
  font-size: 1.45rem;
  color: var(--primary-deep);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.badge-tag {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
}

.badge-tag.oauth {
  background: #EFF6FF;
  color: #1D4ED8;
  border: 1px solid #BFDBFE;
}

.badge-tag.verified {
  background: #ECFDF5;
  color: #047857;
  border: 1px solid #A7F3D0;
}

/* Grid */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 16px;
}

.feature-box {
  background: #FAFAF9;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
}

.feature-box h3 {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: var(--primary-jade);
  margin-bottom: 8px;
}

/* Legal Document Layout */
.legal-content {
  background: var(--surface);
  border-radius: 12px;
  border: 1px solid var(--border);
  padding: 48px 40px;
  margin: 32px auto;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
}

.legal-header {
  border-bottom: 2px solid var(--border);
  padding-bottom: 24px;
  margin-bottom: 32px;
}

.legal-header h1 {
  font-family: var(--font-serif);
  font-size: 2.1rem;
  color: var(--primary-deep);
  margin-bottom: 8px;
}

.legal-meta {
  font-size: 0.9rem;
  color: var(--text-muted);
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.legal-meta strong {
  color: var(--text-heading);
}

.legal-content h2 {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  color: var(--primary-deep);
  margin: 32px 0 12px;
  padding-top: 8px;
  border-top: 1px dashed var(--border);
}

.legal-content h3 {
  font-size: 1.1rem;
  color: var(--text-heading);
  margin: 20px 0 8px;
}

.legal-content p, .legal-content ul, .legal-content ol {
  margin-bottom: 16px;
}

.legal-content ul, .legal-content ol {
  padding-left: 24px;
}

.legal-content li {
  margin-bottom: 6px;
}

/* Callout Box */
.callout {
  background: #FEF3C7;
  border-left: 4px solid var(--accent-gold);
  padding: 16px 20px;
  border-radius: 0 8px 8px 0;
  margin: 24px 0;
  font-size: 0.95rem;
  color: #78350F;
}

.callout-title {
  font-weight: 700;
  margin-bottom: 4px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.callout.google {
  background: #F0FDF4;
  border-left-color: var(--primary-jade);
  color: #064E3B;
}

.callout.disclaimer {
  background: #FFFBEB;
  border-left-color: #D97706;
  color: #92400E;
}

/* Footer */
.site-footer {
  background: #1C1917;
  color: #D6D3D1;
  padding: 48px 0 24px;
  font-size: 0.9rem;
  margin-top: 60px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px;
  margin-bottom: 32px;
}

.footer-col h4 {
  color: #FFFFFF;
  font-family: var(--font-serif);
  font-size: 1.05rem;
  margin-bottom: 14px;
  border-bottom: 1px solid #44403C;
  padding-bottom: 8px;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: #A8A29E;
  text-decoration: none;
  transition: color 0.2s ease;
}

.footer-col a:hover {
  color: #F59E0B;
}

.footer-bottom {
  border-top: 1px solid #292524;
  padding-top: 20px;
  text-align: center;
  color: #78716C;
  font-size: 0.85rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 6px;
  font-weight: 600;
  text-decoration: none;
  font-size: 0.95rem;
  transition: all 0.2s ease;
  cursor: pointer;
}

.btn-primary {
  background: var(--primary-deep);
  color: #FFFFFF;
  border: 1px solid var(--primary-deep);
}

.btn-primary:hover {
  background: var(--primary-jade);
  border-color: var(--primary-jade);
}

.btn-secondary {
  background: var(--surface);
  color: var(--primary-deep);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--primary-deep);
}

/* Responsive */
@media (max-width: 640px) {
  .hero h1 {
    font-size: 1.8rem;
  }
  .legal-content {
    padding: 24px 16px;
  }
  .nav-links {
    gap: 12px;
    font-size: 0.85rem;
  }
}