/* ===== DARK MODE / LIGHT MODE ===== */
:root {
  --bg-primary: #f8fafb;
  --bg-secondary: #ffffff;
  --bg-section: #f9f9f9;
  --text-primary: #1a1a2e;
  --text-secondary: #4a4a6a;
  --text-muted: #6b7280;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-light: rgba(79, 70, 229, 0.08);
  --border: #e5e7eb;
  --card-shadow: 0 2px 8px rgba(0,0,0,0.06);
  --hero-gradient: linear-gradient(135deg, #4f46e5, #7c3aed, #ec4899);
  --nav-bg: rgba(255,255,255,0.92);
  --nav-shadow: 0 1px 8px rgba(0,0,0,0.08);
  --code-bg: #f1f5f9;
  --table-header: #4f46e5;
  --toggle-bg: #e5e7eb;
}

[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-section: #1e293b;
  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #818cf8;
  --accent-hover: #a5b4fc;
  --accent-light: rgba(129, 140, 248, 0.1);
  --border: #334155;
  --card-shadow: 0 2px 8px rgba(0,0,0,0.3);
  --hero-gradient: linear-gradient(135deg, #312e81, #581c87, #831843);
  --nav-bg: rgba(15,23,42,0.95);
  --nav-shadow: 0 1px 8px rgba(0,0,0,0.4);
  --code-bg: #1e293b;
  --table-header: #312e81;
  --toggle-bg: #334155;
}

/* ===== SITE NAV ===== */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.6rem 1.25rem;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--nav-shadow);
  border-bottom: 1px solid var(--border);
  font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
}

.site-nav a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.35rem 0.6rem;
  border-radius: 6px;
  transition: background 0.2s, color 0.2s;
  white-space: nowrap;
}

.site-nav a:hover {
  background: var(--accent-light);
  color: var(--accent-hover);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.nav-brand {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-primary) !important;
  letter-spacing: -0.02em;
}

.nav-sep {
  color: var(--text-muted);
  font-size: 0.75rem;
  user-select: none;
}

/* Theme toggle */
.theme-toggle {
  background: var(--toggle-bg);
  border: 1px solid var(--border);
  border-radius: 9999px;
  width: 2.5rem;
  height: 1.5rem;
  cursor: pointer;
  position: relative;
  flex-shrink: 0;
  transition: background 0.3s;
}

.theme-toggle::after {
  content: '';
  position: absolute;
  top: 2px;
  left: 2px;
  width: 1.15rem;
  height: 1.15rem;
  border-radius: 50%;
  background: #fbbf24;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
  transition: transform 0.3s, background 0.3s;
}

[data-theme="dark"] .theme-toggle::after {
  transform: translateX(1rem);
  background: #818cf8;
}

/* ===== PREV / NEXT NAV ===== */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin: 2.5rem 0 1.5rem;
  padding: 1.25rem 0;
  border-top: 1px solid var(--border);
  font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
}

.lesson-nav a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: all 0.2s;
  background: var(--bg-secondary);
}

.lesson-nav a:hover {
  background: var(--accent-light);
  border-color: var(--accent);
}

.lesson-nav .spacer {
  flex: 1;
}

/* ===== MOBILE ===== */
@media (max-width: 768px) {
  .site-nav {
    flex-wrap: wrap;
    padding: 0.5rem 0.75rem;
    gap: 0.4rem;
  }

  .nav-links {
    order: 2;
    width: 100%;
    justify-content: center;
    gap: 0.1rem;
  }

  .nav-brand {
    font-size: 0.85rem;
  }

  .site-nav a {
    font-size: 0.78rem;
    padding: 0.3rem 0.45rem;
  }

  .lesson-nav {
    flex-direction: column;
    gap: 0.75rem;
  }

  .lesson-nav a {
    width: 100%;
    justify-content: center;
  }
}

/* ===== GLOBAL DARK MODE OVERRIDES ===== */
[data-theme="dark"] body {
  background-color: var(--bg-primary) !important;
  color: var(--text-primary) !important;
}

[data-theme="dark"] .section,
[data-theme="dark"] .example-box,
[data-theme="dark"] .practice-box,
[data-theme="dark"] .cultural-note,
[data-theme="dark"] .pos-card,
[data-theme="dark"] .verb-card,
[data-theme="dark"] .sound-card,
[data-theme="dark"] .number-card,
[data-theme="dark"] .time-card,
[data-theme="dark"] .language-card,
[data-theme="dark"] .scenario-card,
[data-theme="dark"] .ai-tool-card,
[data-theme="dark"] .family-tree,
[data-theme="dark"] .interactive-chat,
[data-theme="dark"] .pronoun-card,
[data-theme="dark"] .relationship-card,
[data-theme="dark"] .social-hierarchy,
[data-theme="dark"] .word-anatomy,
[data-theme="dark"] .interactive-sentence,
[data-theme="dark"] .vocab-card,
[data-theme="dark"] .search-container,
[data-theme="dark"] .stats-bar,
[data-theme="dark"] .alphabet-nav,
[data-theme="dark"] .daily-schedule,
[data-theme="dark"] .progress-tracker,
[data-theme="dark"] .interactive-demo,
[data-theme="dark"] .workflow-visual {
  background-color: var(--bg-secondary) !important;
  color: var(--text-primary) !important;
  border-color: var(--border) !important;
}

[data-theme="dark"] .section {
  border-left-color: var(--accent) !important;
}

[data-theme="dark"] h1,
[data-theme="dark"] h2,
[data-theme="dark"] h3,
[data-theme="dark"] h4 {
  background-color: var(--table-header) !important;
  color: #e2e8f0 !important;
}

[data-theme="dark"] strong {
  color: var(--text-primary) !important;
}

[data-theme="dark"] a {
  color: var(--accent) !important;
}

[data-theme="dark"] table,
[data-theme="dark"] td,
[data-theme="dark"] tr,
[data-theme="dark"] th {
  border-color: var(--border) !important;
}

[data-theme="dark"] th,
[data-theme="dark"] .conjugation-table th,
[data-theme="dark"] .comparison-table th,
[data-theme="dark"] .formation-table th,
[data-theme="dark"] .pronoun-table th {
  background-color: var(--table-header) !important;
}

[data-theme="dark"] code, [data-theme="dark"] pre {
  background-color: var(--code-bg) !important;
}

[data-theme="dark"] blockquote {
  background-color: var(--bg-secondary) !important;
  color: var(--text-primary) !important;
}

[data-theme="dark"] .search-box {
  background: var(--bg-secondary) !important;
  color: var(--text-primary) !important;
  border-color: var(--border) !important;
}

[data-theme="dark"] .pronunciation-guide {
  background: var(--bg-secondary) !important;
  color: var(--text-primary) !important;
}

[data-theme="dark"] .mermaid_container,
[data-theme="dark"] .mermaid-diagram,
[data-theme="dark"] .mermaid {
  background-color: var(--bg-secondary) !important;
  border-color: var(--border) !important;
}

[data-theme="dark"] canvas {
  border-color: var(--border) !important;
}

/* Dark mode for lesson 9 specific elements */
[data-theme="dark"] .category-section {
  background: var(--bg-secondary) !important;
  border-left-color: var(--accent) !important;
  color: var(--text-primary) !important;
}

[data-theme="dark"] .category-title {
  color: var(--accent) !important;
  background: none !important;
}

[data-theme="dark"] .tagalog-word {
  color: var(--accent) !important;
}

[data-theme="dark"] .english-meaning {
  color: var(--text-secondary) !important;
}

[data-theme="dark"] .word-type {
  background: var(--bg-primary) !important;
  color: var(--text-muted) !important;
}

[data-theme="dark"] .example-sentence {
  background: var(--bg-primary) !important;
  color: var(--text-secondary) !important;
}

[data-theme="dark"] .pronunciation {
  color: #f87171 !important;
}

[data-theme="dark"] .meaning {
  color: var(--text-muted) !important;
}