@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@500;600;700;800&family=Plus+Jakarta+Sans:ital,wght@0,400;0,500;0,600;0,700;0,800;1,400;1,500;1,600&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ==========================================================================
   DESIGN SYSTEM - CLEAN, WARM, HUMAN INDIE EDUCATIONAL UI
   ========================================================================== */
:root {
  /* Light Theme (Slate Neutral & Crisp Off-White) */
  --bg-primary: #F8FAFC;       /* Slate 50 */
  --bg-secondary: #FFFFFF;     /* Pure White */
  --bg-tertiary: #F1F5F9;      /* Slate 100 */
  --bg-card: #FFFFFF;
  --bg-card-hover: #F8FAFC;
  --bg-glass: rgba(255, 255, 255, 0.92);
  --bg-glass-strong: rgba(255, 255, 255, 0.98);
  
  --border-subtle: #E2E8F0;     /* Slate 200 */
  --border-medium: #CBD5E1;     /* Slate 300 */
  --border-strong: #94A3B8;     /* Slate 400 */
  --border-focus: #4F46E5;      /* Indigo 600 */
  
  --text-primary: #0F172A;      /* Slate 900 */
  --text-secondary: #334155;    /* Slate 700 */
  --text-muted: #64748B;        /* Slate 500 */
  --text-inverse: #FFFFFF;
  
  /* Primary Action Colors (Warm, Trustworthy Indigo & Emerald) */
  --primary: #4F46E5;           /* Indigo 600 */
  --primary-hover: #4338CA;     /* Indigo 700 */
  --primary-light: #EEF2FF;     /* Indigo 50 */
  --primary-border: #C7D2FE;    /* Indigo 200 */
  --primary-text: #3730A3;      /* Indigo 800 */
  
  --emerald: #059669;          /* Emerald 600 */
  --emerald-hover: #047857;
  --emerald-light: #ECFDF5;
  --emerald-border: #A7F3D0;
  --emerald-text: #065F46;
  
  --coral: #E11D48;            /* Rose/Coral 600 */
  --coral-light: #FFF1F2;
  --coral-border: #FECDD3;
  --coral-text: #9F1239;

  --amber: #D97706;            /* Amber 600 */
  --amber-light: #FEF3C7;
  --amber-border: #FDE68A;
  --amber-text: #92400E;

  --cyan: #0891B2;             /* Cyan 600 */
  --cyan-light: #ECFEFF;
  --cyan-border: #A5F3FC;
  --cyan-text: #155E75;

  --purple: #7C3AED;           /* Purple 600 */
  --purple-light: #F5F3FF;
  --purple-border: #DDD6FE;
  --purple-text: #5B21B6;
  
  /* Natural Drop Shadows (Zero Neon Glows) */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

  /* Radius */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-pill: 9999px;

  /* Typography */
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.2s ease;
  --transition-smooth: 0.3s cubic-bezier(0.16, 1, 0.3, 1);

  --max-width: 1200px;
  --header-height: 72px;
}

/* Dark Theme (Deep Warm Slate & Midnight Charcoal) */
[data-theme="dark"] {
  --bg-primary: #0B0F19;       /* Deep Navy/Black */
  --bg-secondary: #111827;     /* Slate 900 */
  --bg-tertiary: #1E293B;      /* Slate 800 */
  --bg-card: #131D31;
  --bg-card-hover: #192640;
  --bg-glass: rgba(17, 24, 39, 0.92);
  --bg-glass-strong: rgba(17, 24, 39, 0.98);
  
  --border-subtle: #1E293B;     /* Slate 800 */
  --border-medium: #334155;     /* Slate 700 */
  --border-strong: #475569;     /* Slate 600 */
  --border-focus: #6366F1;      /* Indigo 500 */
  
  --text-primary: #F8FAFC;      /* Slate 50 */
  --text-secondary: #CBD5E1;    /* Slate 300 */
  --text-muted: #94A3B8;        /* Slate 400 */
  --text-inverse: #0F172A;
  
  --primary: #6366F1;           /* Indigo 500 */
  --primary-hover: #818CF8;
  --primary-light: rgba(99, 102, 241, 0.15);
  --primary-border: rgba(99, 102, 241, 0.3);
  --primary-text: #C7D2FE;
  
  --emerald: #10B981;          /* Emerald 500 */
  --emerald-hover: #34D399;
  --emerald-light: rgba(16, 185, 129, 0.15);
  --emerald-border: rgba(16, 185, 129, 0.3);
  --emerald-text: #A7F3D0;
  
  --coral: #FB7185;            /* Rose 400 */
  --coral-light: rgba(251, 113, 133, 0.15);
  --coral-border: rgba(251, 113, 133, 0.3);
  --coral-text: #FECDD3;

  --amber: #FBBF24;            /* Amber 400 */
  --amber-light: rgba(251, 191, 36, 0.15);
  --amber-border: rgba(251, 191, 36, 0.3);
  --amber-text: #FDE68A;

  --cyan: #38BDF8;             /* Sky/Cyan 400 */
  --cyan-light: rgba(56, 189, 248, 0.15);
  --cyan-border: rgba(56, 189, 248, 0.3);
  --cyan-text: #BAE6FD;

  --purple: #A78BFA;           /* Purple 400 */
  --purple-light: rgba(167, 139, 250, 0.15);
  --purple-border: rgba(167, 139, 250, 0.3);
  --purple-text: #DDD6FE;

  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.5), 0 1px 2px -1px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.6), 0 4px 6px -4px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.7), 0 8px 10px -6px rgba(0, 0, 0, 0.6);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  max-width: 100vw;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg, video {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast), background-color var(--transition-fast), border-color var(--transition-fast);
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
  border: none;
  background: none;
  outline: none;
}

button {
  cursor: pointer;
  user-select: none;
}

button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

ul, ol {
  list-style: none;
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.025em;
}

h1 { font-size: clamp(2rem, 4.5vw, 3.1rem); letter-spacing: -0.035em; }
h2 { font-size: clamp(1.6rem, 3.2vw, 2.2rem); }
h3 { font-size: clamp(1.2rem, 2vw, 1.45rem); }
h4 { font-size: 1.1rem; }

p {
  color: var(--text-secondary);
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

@media (min-width: 768px) {
  .container {
    padding-left: 2rem;
    padding-right: 2rem;
  }
}

.main-content {
  flex: 1;
  padding-top: var(--header-height);
}

.section {
  padding: 4.5rem 0;
  position: relative;
}

.section-sm {
  padding: 2.75rem 0;
}

/* Badges / Status Chips */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-pill);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  border: 1px solid transparent;
  width: fit-content;
  white-space: nowrap;
}

.badge-indigo { background: var(--primary-light); color: var(--primary-text); border-color: var(--primary-border); }
.badge-emerald { background: var(--emerald-light); color: var(--emerald-text); border-color: var(--emerald-border); }
.badge-coral { background: var(--coral-light); color: var(--coral-text); border-color: var(--coral-border); }
.badge-amber { background: var(--amber-light); color: var(--amber-text); border-color: var(--amber-border); }
.badge-cyan { background: var(--cyan-light); color: var(--cyan-text); border-color: var(--cyan-border); }
.badge-purple { background: var(--purple-light); color: var(--purple-text); border-color: var(--purple-border); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.68rem 1.35rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.92rem;
  transition: all var(--transition-fast);
  white-space: nowrap;
  border: 1px solid transparent;
}

.btn-primary {
  background-color: var(--primary);
  color: #FFFFFF;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-medium);
  box-shadow: var(--shadow-xs);
}

.btn-secondary:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-strong);
  transform: translateY(-1px);
}

.btn-outline {
  border: 1px solid var(--border-medium);
  color: var(--text-secondary);
  background: transparent;
}

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

.btn-sm {
  padding: 0.4rem 0.85rem;
  font-size: 0.82rem;
  border-radius: var(--radius-sm);
}

.btn-lg {
  padding: 0.85rem 1.65rem;
  font-size: 1rem;
  border-radius: var(--radius-md);
}

.btn:active {
  transform: translateY(0);
}

/* ==========================================================================
   HEADER & NAVIGATION
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.3rem;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.brand-icon-box {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #FFFFFF;
  box-shadow: var(--shadow-sm);
}

.brand-accent {
  color: var(--primary);
}

.brand-tagline {
  display: none;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  border-left: 1px solid var(--border-medium);
  padding-left: 0.75rem;
  margin-left: 0.25rem;
}

@media (min-width: 1100px) {
  .brand-tagline {
    display: inline-block;
  }
}

.nav-desktop {
  display: none;
  align-items: center;
  gap: 0.25rem;
}

@media (min-width: 900px) {
  .nav-desktop {
    display: flex;
  }
}

.nav-link {
  padding: 0.5rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
}

.nav-link.active {
  color: var(--primary);
  background-color: var(--primary-light);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

/* Quick Search Trigger */
.search-trigger-btn {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.45rem 0.85rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-pill);
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.search-trigger-btn:hover {
  border-color: var(--border-medium);
  color: var(--text-primary);
  background: var(--bg-card);
}

.search-shortcut-badge {
  background: var(--bg-card);
  border: 1px solid var(--border-medium);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
}

/* Theme Toggle Button */
.theme-toggle-btn {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.theme-toggle-btn:hover {
  color: var(--primary);
  background: var(--bg-card);
  border-color: var(--border-medium);
}

.mobile-menu-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
}

@media (min-width: 900px) {
  .mobile-menu-btn {
    display: none;
  }
}

/* ==========================================================================
   MOBILE DRAWER NAVIGATION
   ========================================================================== */
.mobile-nav-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
  z-index: 1100;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.mobile-nav-backdrop.open {
  opacity: 1;
  visibility: visible;
}

.mobile-nav-drawer {
  position: fixed;
  top: 0;
  right: 0;
  width: 310px;
  max-width: 85vw;
  height: 100vh;
  background: var(--bg-secondary);
  z-index: 1200;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  box-shadow: var(--shadow-xl);
  transform: translateX(100%);
  transition: transform var(--transition-smooth);
  overflow-y: auto;
}

.mobile-nav-backdrop.open .mobile-nav-drawer {
  transform: translateX(0);
}

.mobile-nav-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.mobile-nav-links {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.mobile-nav-links .nav-link {
  padding: 0.75rem 1rem;
  font-size: 0.95rem;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.site-footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: 4rem 0 2rem;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 2.5rem;
  margin-bottom: 3rem;
}

@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 600px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.75rem;
  }
}

.footer-brand p {
  margin-top: 0.85rem;
  margin-bottom: 1.25rem;
  max-width: 340px;
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-heading {
  font-size: 0.92rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer-links-list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.footer-links-list a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.75rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.85rem;
  color: var(--text-muted);
  gap: 1rem;
}

.social-links {
  display: flex;
  gap: 0.5rem;
}

.social-icon-btn {
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.social-icon-btn:hover {
  background: var(--primary);
  border-color: var(--primary);
  color: #FFFFFF;
}

/* ==========================================================================
   GLOBAL SEARCH MODAL
   ========================================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(6px);
  z-index: 2000;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 4rem 1.25rem 2rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.modal-backdrop.open {
  opacity: 1;
  visibility: visible;
}

.search-modal-container {
  background: var(--bg-card);
  width: 100%;
  max-width: 640px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border-medium);
  overflow: hidden;
  transform: translateY(-12px) scale(0.99);
  transition: transform var(--transition-smooth);
}

.modal-backdrop.open .search-modal-container {
  transform: translateY(0) scale(1);
}

.search-modal-header {
  display: flex;
  align-items: center;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
  gap: 0.75rem;
  background: var(--bg-secondary);
}

.search-modal-input {
  flex: 1;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-primary);
}

.search-modal-input::placeholder {
  color: var(--text-muted);
}

.search-modal-results {
  max-height: 420px;
  overflow-y: auto;
  padding: 0.75rem;
}

.search-result-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 0.9rem;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
  cursor: pointer;
}

.search-result-item:hover {
  background: var(--bg-tertiary);
}

.search-result-info {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.search-result-title {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.92rem;
}

.search-result-category {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.search-modal-footer {
  padding: 0.65rem 1.25rem;
  background: var(--bg-tertiary);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.78rem;
  color: var(--text-muted);
}