/* ============================================
   Shared Layout Styles - Navbar & Footer
   ============================================ */

/* CSS Variables */
:root {
  --color-primary: #2563EB;
  --color-secondary: #3B82F6;
  --color-cta: #F97316;
  --color-bg: #FFFFFF;
  --color-text: #1E293B;
  --color-glass-bg: rgba(255, 255, 255, 0.7);
  --color-glass-border: rgba(255, 255, 255, 0.2);
  --color-input-bg: rgba(255, 255, 255, 0.9);
  --color-accent: #1D4ED8;
  
  --font-heading: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 60px;
  
  --z-base: 1;
  --z-nav: 20;
  --z-modal: 30;
}

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

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Background Animation */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: 
    radial-gradient(circle at 20% 30%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(59, 130, 246, 0.12) 0%, transparent 50%),
    radial-gradient(circle at 50% 50%, rgba(249, 115, 22, 0.08) 0%, transparent 50%);
  animation: gradientMove 20s ease infinite;
  z-index: 0;
  pointer-events: none;
}

@keyframes gradientMove {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.8; transform: scale(1.05); }
}

/* ============================================
   Navigation Bar
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  padding: 10px 20px;
  z-index: var(--z-nav);
  transition: all var(--transition-smooth);
  background: 
    linear-gradient(135deg, rgba(219, 234, 254, 0.98) 0%, rgba(239, 246, 255, 0.95) 25%, rgba(255, 255, 255, 0.95) 50%, rgba(225, 239, 254, 0.95) 75%, rgba(219, 234, 254, 0.98) 100%),
    linear-gradient(180deg, #EFF6FF 0%, #DBEAFE 100%);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 4px 24px rgba(37, 99, 235, 0.08);
  border-bottom: 1px solid rgba(37, 99, 235, 0.12);
  animation: slideDown 0.5s ease;
}

@keyframes slideDown {
  from {
    transform: translateY(-100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.75);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 4px 24px rgba(37, 99, 235, 0.1);
  border-bottom: 1px solid var(--color-glass-border);
}

.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 700;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  text-decoration: none;
  transition: transform var(--transition-fast);
  white-space: nowrap;
}

.logo img {
  height: 60px;
  width: auto;
}

.logo:hover {
  transform: scale(1.02);
}

.nav-links {
  display: flex;
  gap: var(--space-md);
  align-items: center;
}

.nav-link {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  padding: var(--space-xs) var(--space-sm);
  border-radius: 8px;
  transition: all var(--transition-fast);
  cursor: pointer;
  min-height: 44px;
  display: flex;
  align-items: center;
}

.nav-link:hover {
  background: rgba(37, 99, 235, 0.1);
  color: var(--color-primary);
}

.nav-link:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ============================================
   Site Footer
   ============================================ */
.site-footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 12px var(--space-lg);
  z-index: var(--z-base);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-top: 1px solid rgba(37, 99, 235, 0.1);
  animation: slideUp 0.5s ease 0.1s both;
}

@keyframes slideUp {
  from {
    transform: translateY(100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
}

.beian-info {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: 14px;
  color: var(--color-text);
}

.beian-icon {
  height: 16px;
  width: auto;
}

.beian-info a {
  color: var(--color-text);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.beian-info a:hover {
  color: var(--color-primary);
}

.copyright {
  font-size: 13px;
  color: var(--color-text);
  opacity: 0.7;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
  .navbar {
    padding: 8px 12px;
  }

  .nav-links {
    gap: var(--space-sm);
  }

  .nav-link {
    padding: 6px 12px;
    font-size: 14px;
  }

  .logo {
    font-size: 16px;
  }

  .site-footer {
    padding: 8px 16px;
  }
}

@media (max-width: 480px) {
  .nav-links {
    gap: 8px;
  }

  .nav-link {
    display: none;
  }

  .nav-link.active {
    display: block;
  }

  .logo {
    font-size: 14px;
  }

  .logo img {
    height: 40px;
  }
}