/* ========================================
   CSS Variables for Theming
   ======================================== */
:root {
  /* European University Brand Colors */
  --color-eu-blue: #1e40af;
  --color-eu-blue-dark: #1e3a8a;
  --color-eu-blue-light: #3b82f6;
  --color-eu-gold: #f59e0b;
  --color-eu-gold-dark: #d97706;
  --color-eu-gold-light: #fbbf24;
  
  /* Light Theme Colors */
  --color-primary: #1e40af;
  --color-primary-dark: #1e3a8a;
  --color-primary-light: #3b82f6;
  --color-secondary: #10b981;
  --color-accent: #f59e0b;
  
  --color-bg-primary: #ffffff;
  --color-bg-secondary: #f9fafb;
  --color-bg-tertiary: #f3f4f6;
  --color-bg-elevated: #ffffff;
  
  --color-text-primary: #111827;
  --color-text-secondary: #6b7280;
  --color-text-tertiary: #9ca3af;
  
  --color-border: #e5e7eb;
  --color-border-light: #f3f4f6;
  
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-info: #3b82f6;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
}

/* ========================================
   Component Loading States
   ======================================== */
/* Placeholders start invisible */
#header-placeholder,
#footer-placeholder {
  opacity: 0;
  transition: opacity var(--transition-base);
}

/* Show placeholders when loaded */
#header-placeholder.loaded,
#footer-placeholder.loaded {
  opacity: 1;
}

/* Prevent layout shift while loading */
#header-placeholder:empty {
  min-height: 70px;
}

#footer-placeholder:empty {
  min-height: 200px;
}

/* Dark Theme */
[data-theme="dark"] {
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-primary-light: #60a5fa;
  
  --color-bg-primary: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-bg-tertiary: #334155;
  --color-bg-elevated: #1e293b;
  
  --color-text-primary: #f1f5f9;
  --color-text-secondary: #cbd5e1;
  --color-text-tertiary: #94a3b8;
  
  --color-border: #334155;
  --color-border-light: #475569;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
}

/* ========================================
   Base Styles
   ======================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  /* Прибираємо білий спалах при кліку в темній темі */
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
}

/* Вимикаємо outline для кліків мишкою, але залишаємо для клавіатури */
*:focus:not(:focus-visible) {
  outline: none;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  /* Запобігає білому спалаху при завантаженні */
  background-color: #ffffff;
}

/* Встановлюємо темний фон для html якщо тема темна */
html[data-theme="dark"] {
  background-color: #0f172a;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* Плавний перехід теми, але без блимання при кліках */
  transition: background-color var(--transition-slow), color var(--transition-slow);
  /* Мінімальна висота для запобігання стрибків */
  min-height: 100vh;
}

/* Запобігаємо блиманню при завантаженні сторінки */
body:not(.loaded) {
  opacity: 0;
}

body.loaded {
  opacity: 1;
  transition: opacity 0.15s ease-in;
}

/* SPA Navigation - Page Transition */
main, section, .hero {
  transition: opacity var(--transition-slow) ease-in-out;
}

body.page-transitioning {
  pointer-events: none;
}

/* ========================================
   Typography
   ======================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  color: var(--color-text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  h3 { font-size: 1.375rem; }
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--color-text-secondary);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

strong {
  font-weight: 600;
  color: var(--color-text-primary);
}

code, pre {
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

/* ========================================
   Container & Layout
   ======================================== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

@media (max-width: 768px) {
  .container {
    padding: 0 var(--spacing-md);
  }
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-alt {
  background-color: var(--color-bg-secondary);
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: var(--spacing-xl);
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  text-align: center;
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-2xl);
}

/* ========================================
   Header & Navigation
   ======================================== */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) var(--spacing-lg);
  max-width: 1200px;
  margin: 0 auto;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-primary);
}

.logo-icon {
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

.logo-icon svg {
  width: 100%;
  height: 100%;
  display: block;
}

.logo-icon img {
  width: 100%;
  height: 100%;
  display: block;
}

.logo-text-container {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.logo-text {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: 1.2;
}

.logo-separator {
  flex-shrink: 0;
}

@media (max-width: 768px) {
  .logo-separator {
    display: none;
  }
  
  .logo-text {
    font-size: 0.875rem;
  }
  
  .logo-icon img {
    max-width: 100px;
  }
}

.theme-toggle {
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  cursor: pointer;
  font-size: 1.25rem;
  transition: background-color var(--transition-fast), transform var(--transition-fast), border-color var(--transition-fast);
  /* Прибираємо спалах при кліку */
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.theme-toggle:hover {
  background-color: var(--color-bg-tertiary);
  transform: scale(1.05);
}

.theme-toggle:active {
  transform: scale(0.95);
  transition: transform 0.05s ease;
}

.theme-toggle:focus:not(:focus-visible) {
  outline: none;
}

.nav-menu {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
  padding: var(--spacing-md);
  overflow-x: auto;
  scrollbar-width: none;
}

.nav-menu::-webkit-scrollbar {
  display: none;
}

.nav-link {
  color: var(--color-text-secondary);
  font-weight: 500;
  white-space: nowrap;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  /* Прибираємо спалах при кліку */
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

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

.nav-link:active {
  /* Плавний active стан без блимання */
  transform: scale(0.98);
  transition: transform 0.05s ease;
}

.nav-link.active {
  color: var(--color-primary);
  background-color: var(--color-bg-tertiary);
  font-weight: 600;
}

/* Додаткове правило для темної теми */
[data-theme="dark"] .nav-link:active {
  opacity: 0.9;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
  position: relative;
  min-height: 90vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: var(--spacing-3xl) var(--spacing-lg);
  background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at 30% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
              radial-gradient(circle at 70% 50%, rgba(16, 185, 129, 0.1) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  margin-bottom: var(--spacing-lg);
  line-height: 1.1;
}

.gradient-text {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--color-text-secondary);
  max-width: 800px;
  margin: 0 auto var(--spacing-2xl);
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

.scroll-indicator {
  position: absolute;
  bottom: var(--spacing-xl);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--color-text-tertiary);
  font-size: 0.875rem;
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% {
    transform: translateX(-50%) translateY(0);
  }
  50% {
    transform: translateX(-50%) translateY(-10px);
  }
}

.scroll-arrow {
  font-size: 1.5rem;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-lg);
  font-weight: 600;
  font-size: 1rem;
  border: none;
  cursor: pointer;
  transition: transform var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-base);
  text-decoration: none;
  /* Прибираємо спалах при кліку */
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
  transition: background-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

.btn-secondary:hover {
  background-color: var(--color-primary);
  color: white;
}

.btn-secondary:active {
  transform: scale(0.98);
}

/* ========================================
   Cards
   ======================================== */
.intro-grid,
.prompting-grid,
.examples-grid,
.ethics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
  margin-top: var(--spacing-2xl);
}

.intro-card,
.prompting-card,
.example-card,
.ethics-card {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.intro-card:hover,
.prompting-card:hover,
.example-card:hover,
.ethics-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.card-icon,
.example-icon,
.ethics-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
}

.benefit-list {
  list-style: none;
  padding-left: 0;
}

.benefit-list li {
  padding: var(--spacing-sm) 0;
  padding-left: var(--spacing-lg);
  position: relative;
  color: var(--color-text-secondary);
}

.benefit-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-success);
  font-weight: bold;
}

/* ========================================
   Models Table
   ======================================== */
.search-box {
  margin-bottom: var(--spacing-xl);
  display: flex;
  justify-content: center;
}

.search-input {
  width: 100%;
  max-width: 500px;
  padding: var(--spacing-md);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-size: 1rem;
  background-color: var(--color-bg-elevated);
  color: var(--color-text-primary);
  transition: all var(--transition-fast);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.models-table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  margin-bottom: var(--spacing-xl);
}

.models-table {
  width: 100%;
  border-collapse: collapse;
  background-color: var(--color-bg-elevated);
}

.models-table thead {
  background-color: var(--color-bg-tertiary);
}

.models-table th {
  padding: var(--spacing-md);
  text-align: left;
  font-weight: 600;
  color: var(--color-text-primary);
  border-bottom: 2px solid var(--color-border);
}

.models-table td {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

.models-table tbody tr {
  transition: background-color var(--transition-fast);
}

.models-table tbody tr:hover {
  background-color: var(--color-bg-tertiary);
}

.models-table tbody tr:last-child td {
  border-bottom: none;
}

/* ========================================
   Prompting Formula
   ======================================== */
.prompting-formula {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(16, 185, 129, 0.1));
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
  text-align: center;
}

.formula-chain {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  flex-wrap: wrap;
  margin-top: var(--spacing-lg);
}

.formula-item {
  background-color: var(--color-primary);
  color: white;
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-lg);
  font-weight: 600;
  box-shadow: var(--shadow-md);
  animation: fadeInUp 0.5s ease-out backwards;
}

.formula-item:nth-child(2n) { animation-delay: 0.1s; }
.formula-item:nth-child(3n) { animation-delay: 0.2s; }
.formula-item:nth-child(4n) { animation-delay: 0.3s; }

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.arrow {
  color: var(--color-text-tertiary);
  font-size: 1.5rem;
}

/* ========================================
   Prompt Boxes
   ======================================== */
.example-prompt,
.ethics-prompt {
  margin-top: var(--spacing-2xl);
}

.prompt-box {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.prompt-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md);
  background-color: var(--color-bg-tertiary);
  border-bottom: 1px solid var(--color-border);
}

.prompt-lang {
  font-weight: 600;
  color: var(--color-text-primary);
}

.copy-btn {
  background-color: var(--color-primary);
  color: white;
  border: none;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
  /* Прибираємо спалах при кліку */
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.copy-btn:hover {
  background-color: var(--color-primary-dark);
  transform: scale(1.05);
}

.copy-btn:active {
  transform: scale(0.95);
}

.copy-btn:focus:not(:focus-visible) {
  outline: none;
}

.prompt-content {
  padding: var(--spacing-lg);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
  white-space: pre-wrap;
  word-wrap: break-word;
  overflow-x: auto;
  margin: 0;
}

/* ========================================
   Templates
   ======================================== */
.templates-filter {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--spacing-2xl);
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  border: 2px solid var(--color-border);
  background-color: transparent;
  color: var(--color-text-secondary);
  border-radius: var(--radius-full);
  cursor: pointer;
  font-weight: 500;
  transition: border-color var(--transition-fast), color var(--transition-fast), background-color var(--transition-fast), transform var(--transition-fast);
  /* Прибираємо спалах при кліку */
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

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

.filter-btn:active {
  transform: scale(0.97);
}

.filter-btn.active {
  background-color: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

.filter-btn:focus:not(:focus-visible) {
  outline: none;
}

.templates-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--spacing-xl);
}

@media (max-width: 768px) {
  .templates-grid {
    grid-template-columns: 1fr;
  }
}

.template-card {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.template-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.template-card.featured {
  border-color: var(--color-primary);
  border-width: 2px;
}

.template-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--spacing-md);
}

.template-title {
  font-size: 1.25rem;
  margin-bottom: 0;
}

.template-badge {
  background-color: var(--color-primary);
  color: white;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-md);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.template-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.template-content {
  margin-top: var(--spacing-lg);
}

/* ========================================
   Tips & Misc
   ======================================== */
.tip-box {
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.1), rgba(251, 191, 36, 0.1));
  border-left: 4px solid var(--color-accent);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  margin-top: var(--spacing-xl);
}

.tips-section {
  margin-top: var(--spacing-2xl);
  background-color: var(--color-bg-secondary);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
}

.tips-list {
  list-style: none;
  padding-left: 0;
}

.tips-list li {
  padding: var(--spacing-md) 0;
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-border);
}

.tips-list li:last-child {
  border-bottom: none;
}

/* ========================================
   FAQ
   ======================================== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.faq-item:hover {
  box-shadow: var(--shadow-md);
}

.faq-question {
  padding: var(--spacing-lg);
  cursor: pointer;
  font-weight: 600;
  color: var(--color-text-primary);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-question::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--color-primary);
  transition: transform var(--transition-fast);
}

.faq-item[open] .faq-question::after {
  transform: rotate(45deg);
}

.faq-answer {
  padding: 0 var(--spacing-lg) var(--spacing-lg);
  color: var(--color-text-secondary);
  animation: slideDown var(--transition-base);
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ========================================
   Footer
   ======================================== */
.footer {
  background: linear-gradient(180deg, var(--color-bg-secondary) 0%, var(--color-bg-tertiary) 100%);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
  margin-top: var(--spacing-3xl);
  position: relative;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-primary), transparent);
  opacity: 0.5;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: var(--spacing-3xl);
  margin-bottom: var(--spacing-2xl);
}

/* Footer About Section */
.footer-about {
  max-width: 350px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.footer-logo-icon {
  font-size: 2.5rem;
  line-height: 1;
}

.footer-about h3 {
  margin: 0;
  font-size: 1.25rem;
  color: var(--color-text-primary);
  line-height: 1.3;
}

.footer-description {
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--spacing-lg);
  font-size: 0.95rem;
}

.eu-branding {
  display: flex;
  align-items: center;
  padding: var(--spacing-md);
  background-color: var(--color-bg-elevated);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.eu-branding:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.eu-branding img {
  width: 140px;
  height: auto;
  object-fit: contain;
}

/* Footer Social Links */
.footer-social {
  display: flex;
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.social-link:hover {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.social-link svg {
  width: 20px;
  height: 20px;
}

/* Footer Section Titles - Unified Style */
.footer-section-title {
  margin-bottom: var(--spacing-md);
  color: var(--color-text-primary);
  font-size: 0.9rem;
  font-weight: 600;
  text-transform: none;
  letter-spacing: 0.3px;
  position: relative;
  padding-bottom: var(--spacing-sm);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.footer-section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 30px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), transparent);
  border-radius: var(--radius-full);
}

.footer-list {
  list-style: none;
  padding: 0;
  margin: 0;
  line-height: 1.4;
}

.footer-list li {
  margin-bottom: 0;
}

.footer-list a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  line-height: 1.8;
  transition: all var(--transition-fast);
  position: relative;
  padding-left: 0;
  padding-top: 0.1rem;
  padding-bottom: 0.1rem;
}

.footer-list a svg {
  width: 14px;
  height: 14px;
  opacity: 0;
  transform: translateX(-5px);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.footer-list a:hover {
  color: var(--color-primary);
  padding-left: var(--spacing-sm);
}

.footer-list a:hover svg {
  opacity: 1;
  transform: translateX(0);
}

/* Footer Divider */
.footer-divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-border), transparent);
  margin: var(--spacing-2xl) 0;
}

/* Footer Bottom */
.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-lg);
}

.footer-bottom-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
}

.footer-copyright {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  color: var(--color-text-tertiary);
  font-size: 0.875rem;
  margin: 0;
}

.footer-copyright svg {
  width: 16px;
  height: 16px;
  opacity: 0.7;
}

.footer-tagline {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  margin: 0;
  padding: var(--spacing-sm) var(--spacing-lg);
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(16, 185, 129, 0.1));
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
}

/* Footer Responsive Design */
@media (max-width: 1024px) {
  .footer-content {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
  }
  
  .footer-about {
    grid-column: 1 / -1;
    max-width: 100%;
  }
}

@media (max-width: 768px) {
  .footer {
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
  }
  
  .footer-about {
    text-align: center;
    max-width: 100%;
  }
  
  .footer-logo {
    justify-content: center;
  }
  
  .eu-branding {
    justify-content: center;
  }
  
  .footer-social {
    justify-content: center;
  }
  
  .footer-section-title::after {
    left: 50%;
    transform: translateX(-50%);
  }
  
  .footer-bottom-content {
    padding: 0 var(--spacing-md);
  }
  
  .footer-copyright {
    font-size: 0.8rem;
    flex-wrap: wrap;
  }
  
  .footer-tagline {
    font-size: 0.85rem;
    padding: var(--spacing-sm) var(--spacing-md);
  }
}

/* ========================================
   Back to Top Button
   ======================================== */
.back-to-top {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  background-color: var(--color-primary);
  color: white;
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background-color: var(--color-primary-dark);
  transform: translateY(-4px);
}

/* ========================================
   Toast Notification
   ======================================== */
.toast {
  position: fixed;
  bottom: var(--spacing-xl);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background-color: var(--color-success);
  color: white;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  font-weight: 500;
  opacity: 0;
  transition: all var(--transition-base);
  z-index: 9999;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
  .hero {
    min-height: 80vh;
    padding: var(--spacing-2xl) var(--spacing-md);
  }
  
  .formula-chain {
    flex-direction: column;
  }
  
  .arrow {
    transform: rotate(90deg);
  }
  
  .back-to-top {
    bottom: var(--spacing-md);
    right: var(--spacing-md);
    width: 40px;
    height: 40px;
    font-size: 1.25rem;
  }
}

/* ========================================
   Utility Classes
   ======================================== */
.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ========================================
   Author Profiles
   ======================================== */
.author-profile {
  display: flex;
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-3xl);
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  align-items: flex-start;
}

.author-profile:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.author-photo {
  flex-shrink: 0;
  width: 200px;
  height: auto;
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.author-photo img {
  width: 100%;
  height: auto;
  object-fit: contain;
  display: block;
  transition: transform var(--transition-base);
}

.author-profile:hover .author-photo img {
  transform: scale(1.05);
}

.author-info {
  flex: 1;
}

.author-info h3 {
  font-size: 1.75rem;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-primary);
}

.author-bio {
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--spacing-lg);
}

.author-contacts {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.author-link {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-sm) var(--spacing-lg);
  background-color: var(--color-bg-tertiary);
  border-radius: var(--radius-md);
  color: var(--color-text-primary);
  font-weight: 500;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.author-link:hover {
  background-color: var(--color-primary);
  color: white;
  transform: translateY(-2px);
}

/* ========================================
   Detailed Examples Styles
   ======================================== */
.detailed-example {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
  box-shadow: var(--shadow-md);
}

.example-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 2px solid var(--color-border);
}

.example-header .example-icon {
  font-size: 3rem;
  flex-shrink: 0;
}

.example-header h2 {
  margin: 0 0 var(--spacing-xs) 0;
  color: var(--color-primary);
}

.example-meta {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  margin: 0;
}

.example-section {
  margin-bottom: var(--spacing-2xl);
}

.example-section h3 {
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.prompt-example {
  background-color: var(--color-bg-secondary);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

.prompt-label {
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.prompt-code {
  background-color: var(--color-bg-tertiary);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin: var(--spacing-sm) 0 0 0;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--color-text-primary);
  white-space: pre-wrap;
  word-wrap: break-word;
}

.result-box {
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(16, 185, 129, 0.05));
  border-left: 4px solid var(--color-success);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-top: var(--spacing-md);
}

.result-label {
  font-weight: 600;
  color: var(--color-success);
  margin-bottom: var(--spacing-sm);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 0.95rem;
}

.result-box ul {
  margin: var(--spacing-sm) 0 0 var(--spacing-lg);
  color: var(--color-text-secondary);
}

.result-box ul li {
  margin-bottom: var(--spacing-xs);
  line-height: 1.6;
}

.tips-box {
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.1), rgba(245, 158, 11, 0.05));
  border-left: 4px solid var(--color-warning);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.tips-box h4 {
  color: var(--color-warning);
  margin: 0 0 var(--spacing-md) 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.tips-box ul {
  margin: var(--spacing-sm) 0 0 var(--spacing-lg);
  color: var(--color-text-secondary);
}

.tips-box ul li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.6;
}

.general-tips {
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-2xl);
  border-top: 2px solid var(--color-border);
}

.general-tips h2 {
  text-align: center;
  color: var(--color-primary);
  margin-bottom: var(--spacing-2xl);
}

.tip-card {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
  transition: all var(--transition-base);
}

.tip-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.tip-card h3 {
  color: var(--color-primary);
  margin: 0 0 var(--spacing-md) 0;
  font-size: 1.2rem;
}

.tip-card p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.tip-card ul {
  margin: var(--spacing-sm) 0 0 var(--spacing-lg);
  color: var(--color-text-secondary);
}

.tip-card ul li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.6;
}

.tip-card strong {
  color: var(--color-text-primary);
}

/* Responsive Detailed Examples */
@media (max-width: 768px) {
  .detailed-example {
    padding: var(--spacing-lg);
  }

  .example-header {
    flex-direction: column;
    text-align: center;
  }

  .example-header .example-icon {
    font-size: 2.5rem;
  }

  .prompt-code {
    font-size: 0.85rem;
  }
}

/* Responsive Author Profiles */
@media (max-width: 768px) {
  .author-profile {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
  
  .author-photo {
    width: 200px;
    height: auto;
  }
  
  .author-contacts {
    justify-content: center;
  }
}

/* ========================================
   AI Agents Page Styles
   ======================================== */
.agents-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-2xl);
}

.agent-card {
  background: var(--color-card-bg);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-border);
}

.agent-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.agent-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-lg);
}

.agent-icon {
  font-size: 2.5rem;
  line-height: 1;
}

.agent-badge {
  background: var(--gradient-primary);
  color: white;
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.agent-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-md);
}

.agent-description {
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--spacing-sm);
  flex-grow: 1;
}

.agent-features {
  background: var(--color-bg);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius-md);
  margin-bottom: var(--spacing-lg);
}

.agent-features h4 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.agent-features ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.agent-features li {
  padding: 0.15rem 0;
  padding-left: var(--spacing-lg);
  position: relative;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.agent-features li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-success);
  font-weight: bold;
}

.agent-link {
  width: 100%;
  text-align: center;
  padding: var(--spacing-md) var(--spacing-lg);
  font-weight: 600;
  text-decoration: none;
  display: inline-block;
  transition: all var(--transition-base);
}

.agent-link:hover {
  transform: translateX(4px);
}

.usage-guide .step-item {
  margin-bottom: var(--spacing-lg);
}

.usage-guide .step-item h3 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
  font-size: 1.1rem;
}

.usage-guide .step-item p {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.benefits-section {
  margin-top: var(--spacing-2xl);
}

.intro-content {
  max-width: 900px;
  margin: 0 auto var(--spacing-2xl);
}

/* Responsive for Agents */
@media (max-width: 768px) {
  .agents-grid {
    grid-template-columns: 1fr;
  }
  
  .agent-card {
    padding: var(--spacing-lg);
  }
  
  .agent-icon {
    font-size: 2rem;
  }
  
  .agent-title {
    font-size: 1.25rem;
  }
}

/* ========================================
   Print Styles
   ======================================== */
@media print {
  .header,
  .hero-actions,
  .theme-toggle,
  .copy-btn,
  .back-to-top,
  .toast {
    display: none !important;
  }
  
  body {
    background: white;
    color: black;
  }
  
  .section {
    page-break-inside: avoid;
  }
}