/* ===================================
   Bitcoin Price Compare - Design System
   Premium Dark Theme with Glassmorphism
   =================================== */

/* CSS Variables */
:root {
  /* Colors */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-gradient: linear-gradient(135deg, #1a1a2e 0%, #0f0f1a 50%, #16213e 100%);

  /* Glass Effect */
  --glass-bg: rgba(255, 255, 255, 0.03);
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

  /* Bitcoin Orange */
  --btc-orange: #f7931a;
  --btc-orange-glow: rgba(247, 147, 26, 0.3);

  /* Accent Colors */
  --accent-green: #00d4aa;
  --accent-green-glow: rgba(0, 212, 170, 0.3);
  --accent-red: #ff4757;
  --accent-red-glow: rgba(255, 71, 87, 0.3);
  --accent-blue: #5f9fff;
  --accent-purple: #a855f7;

  /* Text */
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.7);
  --text-muted: rgba(255, 255, 255, 0.4);

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* Reset & Base */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

/* Background Animation */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(circle at 20% 80%, var(--btc-orange-glow) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, var(--accent-purple) 0%, transparent 40%),
    radial-gradient(circle at 50% 50%, rgba(95, 159, 255, 0.1) 0%, transparent 60%);
  pointer-events: none;
  z-index: -1;
  animation: backgroundPulse 10s ease-in-out infinite alternate;
}

@keyframes backgroundPulse {
  0% {
    opacity: 0.5;
  }

  100% {
    opacity: 0.8;
  }
}

/* Container */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--spacing-md);
}

/* Header */
.header {
  text-align: center;
  padding: var(--spacing-xl) 0;
  margin-bottom: var(--spacing-lg);
}

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

.logo-icon {
  font-size: 3rem;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {

  0%,
  100% {
    transform: translateY(0);
  }

  50% {
    transform: translateY(-10px);
  }
}

.logo h1 {
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--btc-orange) 0%, #ffd700 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

.tagline {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 500px;
  margin: 0 auto;
}

/* Stats Bar */
.stats-bar {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
  margin-top: var(--spacing-lg);
  padding: var(--spacing-md);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(10px);
}

.stat-item {
  text-align: center;
}

.stat-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: var(--spacing-xs);
}

.stat-value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.stat-value.positive {
  color: var(--accent-green);
}

.stat-value.negative {
  color: var(--accent-red);
}

/* Price Grid */
.price-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

/* Exchange Card */
.exchange-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  backdrop-filter: blur(20px);
  box-shadow: var(--glass-shadow);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.exchange-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--btc-orange), var(--accent-purple));
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.exchange-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 255, 255, 0.15);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

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

.exchange-card.best-price {
  border-color: var(--accent-green);
  box-shadow: 0 0 30px var(--accent-green-glow);
}

.exchange-card.best-price::before {
  background: var(--accent-green);
  opacity: 1;
}

/* Card Header */
.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-md);
}

.exchange-name {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.exchange-logo {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 700;
}

.exchange-logo.binance {
  background: linear-gradient(135deg, #f3ba2f 0%, #d4a017 100%);
  color: #000;
}

.exchange-logo.coinbase {
  background: linear-gradient(135deg, #0052ff 0%, #0037a6 100%);
  color: #fff;
}

.exchange-logo.kraken {
  background: linear-gradient(135deg, #5741d9 0%, #3b2c99 100%);
  color: #fff;
}

.exchange-logo.coingecko {
  background: linear-gradient(135deg, #8dc63f 0%, #5a9a1f 100%);
  color: #fff;
}

.exchange-logo.gemini {
  background: linear-gradient(135deg, #00dcfa 0%, #0097b2 100%);
  color: #000;
}

.exchange-logo.bitstamp {
  background: linear-gradient(135deg, #269f5a 0%, #1a7a42 100%);
  color: #fff;
}

.exchange-logo.okx {
  background: linear-gradient(135deg, #ffffff 0%, #e0e0e0 100%);
  color: #000;
}

.exchange-logo.cryptocom {
  background: linear-gradient(135deg, #002d74 0%, #001a45 100%);
  color: #fff;
}

.exchange-logo.kucoin {
  background: linear-gradient(135deg, #24ae8f 0%, #1a8a6f 100%);
  color: #fff;
}

.exchange-logo.gateio {
  background: linear-gradient(135deg, #eb4d4b 0%, #c92a2a 100%);
  color: #fff;
}

.exchange-logo.bitfinex {
  background: linear-gradient(135deg, #92d275 0%, #6ab04c 100%);
  color: #000;
}

.exchange-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.status-indicator {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent-green);
  box-shadow: 0 0 10px var(--accent-green);
  animation: pulse 2s ease-in-out infinite;
}

.status-indicator.error {
  background: var(--accent-red);
  box-shadow: 0 0 10px var(--accent-red);
}

.status-indicator.loading {
  background: var(--btc-orange);
  box-shadow: 0 0 10px var(--btc-orange);
}

@keyframes pulse {

  0%,
  100% {
    opacity: 1;
    transform: scale(1);
  }

  50% {
    opacity: 0.5;
    transform: scale(0.9);
  }
}

/* Price Display */
.price-display {
  margin-bottom: var(--spacing-md);
}

.current-price {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
  transition: color var(--transition-fast);
}

.current-price.updating {
  animation: priceFlash 0.5s ease;
}

@keyframes priceFlash {

  0%,
  100% {
    text-shadow: none;
  }

  50% {
    text-shadow: 0 0 20px var(--btc-orange-glow);
  }
}

.price-change {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
}

.price-change.positive {
  background: rgba(0, 212, 170, 0.15);
  color: var(--accent-green);
}

.price-change.negative {
  background: rgba(255, 71, 87, 0.15);
  color: var(--accent-red);
}

/* Card Footer */
.card-footer {
  display: flex;
  justify-content: space-between;
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--glass-border);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Best Price Badge */
.best-badge {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  background: linear-gradient(135deg, var(--accent-green) 0%, #00b894 100%);
  color: #000;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: var(--radius-full);
  animation: badgePulse 2s ease-in-out infinite;
}

@keyframes badgePulse {

  0%,
  100% {
    box-shadow: 0 0 10px var(--accent-green-glow);
  }

  50% {
    box-shadow: 0 0 20px var(--accent-green-glow);
  }
}

/* Spread Section */
.spread-section {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  backdrop-filter: blur(20px);
  margin-bottom: var(--spacing-xl);
}

.spread-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.spread-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

.spread-item {
  text-align: center;
  padding: var(--spacing-md);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--radius-md);
}

.spread-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: var(--spacing-xs);
}

.spread-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--btc-orange);
}

/* Footer */
.footer {
  text-align: center;
  padding: var(--spacing-lg) 0;
  color: var(--text-muted);
  font-size: 0.875rem;
}

.footer a {
  color: var(--btc-orange);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer a:hover {
  color: #ffd700;
}

/* Loading State */
.loading-skeleton {
  background: linear-gradient(90deg,
      rgba(255, 255, 255, 0.05) 25%,
      rgba(255, 255, 255, 0.1) 50%,
      rgba(255, 255, 255, 0.05) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
}

@keyframes shimmer {
  0% {
    background-position: 200% 0;
  }

  100% {
    background-position: -200% 0;
  }
}

/* Error State */
.error-message {
  color: var(--accent-red);
  font-size: 0.875rem;
  padding: var(--spacing-sm);
  background: rgba(255, 71, 87, 0.1);
  border-radius: var(--radius-sm);
  text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
  .logo h1 {
    font-size: 1.75rem;
  }

  .logo-icon {
    font-size: 2rem;
  }

  .current-price {
    font-size: 2rem;
  }

  .stats-bar {
    gap: var(--spacing-md);
  }

  .stat-item {
    flex: 1 1 40%;
  }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

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

::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* Auto-refresh Toggle */
.refresh-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.refresh-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.refresh-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--btc-orange);
}

.refresh-btn.active {
  background: rgba(247, 147, 26, 0.2);
  border-color: var(--btc-orange);
  color: var(--btc-orange);
}

.refresh-btn .icon {
  transition: transform var(--transition-normal);
}

.refresh-btn:hover .icon {
  transform: rotate(180deg);
}

.countdown {
  font-size: 0.875rem;
  color: var(--text-muted);
}