/* ===== GOOGLE FONTS IMPORT ===== */
@import url('https://fonts.googleapis.com/css2?family=Orbitron:wght@400;700;900&display=swap');

/* ===== SIMPLIFIED BÖRSE - NEURAL ORBITRON FINTECH THEME ===== */

:root {
  /* Fintech Primary Colors */
  --primary: #0F172A;
  --primary-light: #1E293B;
  --accent-blue: #0EA5E9;
  --accent-cyan: #06B6D4;
  --accent-green: #10B981;
  --accent-purple: #8B5CF6;
  
  /* Neutrals */
  --text-primary: #F1F5F9;
  --text-secondary: #CBD5E1;
  --text-tertiary: #94A3B8;
  --bg-dark: #0F172A;
  --bg-darker: #020617;
  --border-color: #334155;
  
  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  
  /* Typography - ORBITRON FUTURISTIC */
  --font-sans: 'Orbitron', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Menlo', 'Monaco', 'Courier New', monospace;
  
  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  
  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
}

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

html, body {
  height: 100%;
  width: 100%;
}

body {
  font-family: var(--font-sans);
  font-weight: 400;
  background: linear-gradient(135deg, var(--bg-darker) 0%, var(--bg-dark) 100%);
  color: var(--text-primary);
  line-height: 1.6;
  font-size: 16px;
  overflow-x: hidden;
  letter-spacing: 0.5px;
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--accent-cyan), var(--accent-blue));
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(180deg, var(--accent-blue), var(--accent-cyan));
}

/* ===== HERO SECTION ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: var(--spacing-2xl) var(--spacing-lg);
  text-align: center;
  background: linear-gradient(
    135deg,
    rgba(15, 23, 42, 1) 0%,
    rgba(15, 23, 42, 0.95) 50%,
    rgba(30, 41, 59, 1) 100%
  );
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(14, 165, 233, 0.15), transparent 70%);
  border-radius: 50%;
  animation: float 8s ease-in-out infinite;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -15%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.1), transparent 70%);
  border-radius: 50%;
  animation: float 10s ease-in-out infinite reverse;
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(20px); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 900px;
}

.hero h1 {
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 900;
  font-family: 'Orbitron', var(--font-sans);
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue), var(--accent-green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.hero-subtitle {
  font-size: 1.3rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  font-weight: 500;
}

.hero-description {
  font-size: 1.05rem;
  color: var(--text-tertiary);
  margin-bottom: var(--spacing-2xl);
  line-height: 1.8;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== STATS GRID ===== */
.stats-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--spacing-lg);
  max-width: 1200px;
  margin: 0 auto var(--spacing-2xl);
  padding: 0 var(--spacing-lg);
  position: relative;
  z-index: 1;
}

.stat-box {
  background: linear-gradient(135deg, rgba(30, 41, 59, 0.6), rgba(15, 23, 42, 0.4));
  border: 1px solid rgba(14, 165, 233, 0.2);
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(10px);
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.stat-box:hover {
  background: linear-gradient(135deg, rgba(14, 165, 233, 0.1), rgba(6, 182, 212, 0.05));
  border-color: var(--accent-cyan);
  transform: translateY(-4px);
  box-shadow: 0 0 20px rgba(6, 182, 212, 0.3);
}

.stat-number {
  font-size: 2.2rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-sm);
}

.stat-label {
  font-size: 0.95rem;
  color: var(--text-tertiary);
}

/* ===== QUALITY BANNER ===== */
.quality-banner {
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(6, 182, 212, 0.1));
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--text-primary);
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-2xl);
  text-align: center;
  font-size: 1rem;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  backdrop-filter: blur(10px);
}

.quality-banner strong {
  color: var(--accent-green);
}

/* ===== BOOKS GRID ===== */
.books-grid {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg) var(--spacing-2xl);
}

.books-grid-wrapper {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.book-card {
  position: relative;
  background: linear-gradient(135deg, rgba(30, 41, 59, 0.4), rgba(15, 23, 42, 0.6));
  border: 1px solid rgba(14, 165, 233, 0.15);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  backdrop-filter: blur(10px);
  overflow: hidden;
  min-height: 320px;
}

.book-card::before {
  content: '';
  position: absolute;
  top: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.book-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, rgba(6, 182, 212, 0.15), transparent 70%);
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
}

.book-card:hover {
  transform: translateY(-8px);
  border-color: rgba(14, 165, 233, 0.4);
  background: linear-gradient(135deg, rgba(30, 41, 59, 0.6), rgba(15, 23, 42, 0.4));
  box-shadow: 
    0 0 20px rgba(6, 182, 212, 0.2),
    0 8px 32px rgba(0, 0, 0, 0.3);
}

.book-card:hover::before {
  opacity: 1;
}

.book-card:hover::after {
  opacity: 1;
}

.book-icon {
  font-size: 3.5rem;
  margin-bottom: var(--spacing-lg);
  display: block;
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.book-card:hover .book-icon {
  transform: scale(1.2) rotate(8deg);
}

.book-card h3 {
  font-size: 1.6rem;
  margin-bottom: var(--spacing-md);
  min-height: 3em;
  display: flex;
  align-items: center;
  font-weight: 700;
  font-family: 'Orbitron', var(--font-sans);
  background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 0.5px;
}

.book-card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: auto;
  line-height: 1.7;
  min-height: 2.8em;
}

.book-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid rgba(14, 165, 233, 0.1);
}

.book-meta-tag {
  background: linear-gradient(135deg, rgba(14, 165, 233, 0.2), rgba(6, 182, 212, 0.2));
  color: var(--accent-cyan);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid rgba(14, 165, 233, 0.3);
}

.book-meta-arrow {
  font-size: 1.5rem;
  transition: transform 0.3s ease;
}

.book-card:hover .book-meta-arrow {
  transform: translateX(6px);
}

/* ===== BOOK CONTENT STYLES ===== */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  background: linear-gradient(135deg, rgba(14, 165, 233, 0.1), rgba(6, 182, 212, 0.1));
  color: var(--accent-cyan);
  border: 1px solid rgba(14, 165, 233, 0.3);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 0.95rem;
  margin: var(--spacing-lg);
  transition: all 0.3s ease;
  text-decoration: none;
  font-weight: 600;
  backdrop-filter: blur(10px);
}

.back-btn:hover {
  background: linear-gradient(135deg, rgba(14, 165, 233, 0.2), rgba(6, 182, 212, 0.15));
  border-color: var(--accent-cyan);
  transform: translateX(-4px);
}

.book-content {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

.book-content h1 {
  font-size: 3rem;
  font-weight: 900;
  font-family: 'Orbitron', var(--font-sans);
  margin-bottom: var(--spacing-xl);
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 2px;
  text-transform: uppercase;
}

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

.chapter h2 {
  font-size: 1.8rem;
  font-weight: 700;
  font-family: 'Orbitron', var(--font-sans);
  margin-bottom: var(--spacing-lg);
  color: var(--accent-cyan);
  padding-bottom: var(--spacing-md);
  border-bottom: 2px solid rgba(14, 165, 233, 0.2);
  letter-spacing: 1px;
  text-transform: uppercase;
}

.chapter h3 {
  font-size: 1.3rem;
  font-weight: 700;
  font-family: 'Orbitron', var(--font-sans);
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
  color: var(--accent-blue);
  letter-spacing: 0.5px;
}

.chapter p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
  line-height: 1.8;
}

.chapter ul, .chapter ol {
  margin-left: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

.chapter li {
  margin-bottom: var(--spacing-sm);
  color: var(--text-secondary);
  line-height: 1.8;
}

/* ===== INFO BOXES ===== */
.example-box, .warning-box, .tip-box {
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) 0;
  border-left: 4px solid;
  backdrop-filter: blur(10px);
}

.example-box {
  background: rgba(16, 185, 129, 0.1);
  border-color: var(--accent-green);
  border-left: 4px solid var(--accent-green);
}

.warning-box {
  background: rgba(168, 85, 247, 0.1);
  border-color: var(--accent-purple);
  border-left: 4px solid var(--accent-purple);
}

.tip-box {
  background: rgba(14, 165, 233, 0.1);
  border-color: var(--accent-blue);
  border-left: 4px solid var(--accent-blue);
}

.example-box strong, .warning-box strong, .tip-box strong {
  color: var(--text-primary);
}

.example-box, .warning-box, .tip-box {
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

/* ===== CHARTS ===== */
.chart-container {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(14, 165, 233, 0.2);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  margin: var(--spacing-lg) 0;
  display: flex;
  justify-content: center;
  align-items: center;
  backdrop-filter: blur(10px);
}

canvas {
  max-width: 100%;
  height: auto;
}

/* ===== STATS ROW ===== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
  margin: var(--spacing-lg) 0;
}

.stat-card {
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  text-align: center;
  color: white;
  font-weight: 600;
  transition: all 0.3s ease;
}

.stat-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.stat-card .number {
  font-size: 2rem;
  margin-bottom: var(--spacing-sm);
}

.stat-card .label {
  font-size: 0.9rem;
  opacity: 0.9;
}

/* ===== FOOTER ===== */
footer {
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-lg);
  color: var(--text-tertiary);
  border-top: 1px solid rgba(14, 165, 233, 0.1);
  margin-top: var(--spacing-2xl);
}

footer p {
  margin-bottom: var(--spacing-sm);
  line-height: 1.8;
}

footer a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: color 0.3s ease;
}

footer a:hover {
  color: var(--accent-blue);
  text-decoration: underline;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .hero {
    min-height: auto;
    padding: var(--spacing-xl) var(--spacing-md);
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1.1rem;
  }

  .hero-description {
    font-size: 0.95rem;
  }

  .book-content h1 {
    font-size: 2rem;
  }

  .chapter h2 {
    font-size: 1.4rem;
  }

  .chapter h3 {
    font-size: 1.1rem;
  }

  .books-grid-wrapper {
    grid-template-columns: 1fr;
  }

  .stats-container {
    grid-template-columns: repeat(2, 1fr);
  }

  .stat-box {
    padding: var(--spacing-md);
  }

  .stat-number {
    font-size: 1.8rem;
  }
}

@media (max-width: 480px) {
  :root {
    --spacing-lg: 16px;
    --spacing-xl: 20px;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .hero-description {
    font-size: 0.9rem;
  }

  .chapter h2 {
    font-size: 1.2rem;
  }

  .stat-number {
    font-size: 1.5rem;
  }

  .book-card {
    padding: var(--spacing-md);
  }

  .book-icon {
    font-size: 2.5rem;
  }
}