/* CryptoLearnZone.com - Shared Styles */
:root {
  --bg: #0a0e1a;
  --bg-card: #111827;
  --bg-card-hover: #1a2236;
  --bg-header: rgba(10, 14, 26, 0.95);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #00D4AA;
  --accent-light: #34f5c7;
  --accent-dark: #00b38c;
  --accent-glow: rgba(0, 212, 170, 0.15);
  --border: #1e293b;
  --border-light: #334155;
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.1);
  --success: #22c55e;
  --success-bg: rgba(34, 197, 94, 0.1);
  --warning: #f59e0b;
  --warning-bg: rgba(245, 158, 11, 0.1);
  --info: #3b82f6;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.4);
  --max-width: 1200px;
  --header-height: 64px;
  --transition: all 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  color: var(--accent-light);
}

img {
  max-width: 100%;
  display: block;
}

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

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--bg-header);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.logo {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo span {
  color: var(--accent);
}

.logo:hover {
  color: var(--text-primary);
}

.nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
}

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

.nav a.active {
  color: var(--accent);
  background: var(--accent-glow);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: var(--transition);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: var(--accent);
  color: var(--bg);
}

.btn-primary:hover {
  background: var(--accent-light);
  color: var(--bg);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0, 212, 170, 0.3);
}

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

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  color: var(--accent);
}

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

.btn-outline:hover {
  background: var(--accent-glow);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.85rem;
}

.btn-lg {
  padding: 16px 32px;
  font-size: 1.05rem;
}

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: var(--transition);
}

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

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: var(--accent-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.5;
}

/* Page Header */
.page-header {
  padding: calc(var(--header-height) + 48px) 0 40px;
  text-align: center;
}

.page-header h1 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 12px;
  line-height: 1.2;
}

.page-header h1 span {
  color: var(--accent);
}

.page-header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto;
}

/* Section */
.section {
  padding: 60px 0;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 8px;
  text-align: center;
}

.section-subtitle {
  color: var(--text-secondary);
  text-align: center;
  margin-bottom: 40px;
}

/* Grid */
.grid {
  display: grid;
  gap: 24px;
}

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

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* Quiz/Question Styles */
.question-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  margin-bottom: 20px;
}

.question-card h3 {
  font-size: 1.15rem;
  margin-bottom: 20px;
  line-height: 1.5;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
}

.option:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
}

.option input {
  margin-top: 3px;
  accent-color: var(--accent);
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.option label {
  cursor: pointer;
  flex: 1;
  font-size: 0.95rem;
}

.option.correct {
  border-color: var(--success);
  background: var(--success-bg);
}

.option.incorrect {
  border-color: var(--error);
  background: var(--error-bg);
}

/* Progress */
.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--bg-card);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 24px;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 4px;
  transition: width 0.3s ease;
}

/* Results */
.result-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
  margin: 24px 0;
}

.result-score {
  font-size: 3rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 8px;
}

.result-label {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.result-message {
  font-size: 1.1rem;
  margin-bottom: 24px;
}

/* Flashcard */
.flashcard {
  perspective: 1000px;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  min-height: 220px;
  text-align: center;
  transition: transform 0.5s;
  transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-front, .flashcard-back {
  position: absolute;
  width: 100%;
  min-height: 220px;
  backface-visibility: hidden;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.flashcard-back {
  transform: rotateY(180deg);
  background: var(--accent-glow);
  border-color: var(--accent);
}

.flashcard-front h3 {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.flashcard-front small {
  color: var(--text-muted);
  font-size: 0.8rem;
}

.flashcard-back p {
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* Match Game */
.match-item {
  padding: 16px 20px;
  background: var(--bg-card);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  text-align: center;
  font-weight: 500;
  transition: var(--transition);
  user-select: none;
}

.match-item:hover {
  border-color: var(--border-light);
}

.match-item.selected {
  border-color: var(--accent);
  background: var(--accent-glow);
}

.match-item.matched {
  border-color: var(--success);
  background: var(--success-bg);
  opacity: 0.6;
  cursor: default;
}

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  margin-top: 60px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer p {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.85rem;
}

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

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--text-secondary);
}

.breadcrumb a:hover {
  color: var(--accent);
}

/* Utility */
.text-center { text-align: center; }
.text-accent { color: var(--accent); }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }
.hidden { display: none; }

/* Responsive */
@media (max-width: 992px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  
  .hamburger {
    display: flex;
  }
  
  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--bg-header);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
  }
  
  .nav.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav a {
    padding: 10px 12px;
    width: 100%;
  }
  
  .page-header h1 {
    font-size: 1.75rem;
  }
  
  .page-header p {
    font-size: 1rem;
  }
  
  .result-score {
    font-size: 2.5rem;
  }
  
  .footer-inner {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }
  
  .header-inner {
    padding: 0 16px;
  }
  
  .card {
    padding: 20px;
  }
  
  .question-card {
    padding: 20px;
  }
  
  .section {
    padding: 40px 0;
  }
}