/* Reset & Base */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: #0A1628;
  color: #E8ECF0;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
ul { list-style: none; }
a { color: inherit; text-decoration: none; }

/* CSS Variables */
:root {
  --color-deep-blue: #0B1D3A;
  --color-snow-white: #F5F7FA;
  --color-gold: #D4AF37;
  --color-orange: #FF6B35;
  --color-bg-dark: #0A1628;
  --color-card-bg: rgba(255,255,255,0.08);
  --color-text-primary: #E8ECF0;
  --color-text-secondary: #A0AAB5;
  --color-border-subtle: rgba(212,175,55,0.3);
  --color-hover-overlay: rgba(212,175,55,0.1);
  --gradient-hero: linear-gradient(135deg, #0A1628 0%, #1A2A4A 100%);
  --font-heading: 'Noto Sans Tibetan', 'Tibetan Serif', serif;
  --font-body: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --max-width: 1200px;
  --header-height: 64px;
  --transition-base: 0.3s ease;
}

/* Shared Container */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-gold);
  color: #0A1628;
  padding: 8px 16px;
  z-index: 1000;
  font-weight: 600;
  transition: top 0.2s;
}
.skip-link:focus {
  top: 0;
}

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 500;
  background: rgba(10,22,40,0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border-subtle);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}
.logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  background: var(--color-deep-blue);
  color: var(--color-gold);
  padding: 0.3rem 0.8rem;
  border-radius: 4px;
  letter-spacing: 0.05em;
  transition: opacity var(--transition-base);
}
.logo:hover { opacity: 0.9; }

/* Navigation Toggle (Hamburger) */
.nav-toggle {
  display: none; /* shown on mobile */
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--color-snow-white);
  font-size: 1.5rem;
}
.nav-toggle-icon {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-snow-white);
  position: relative;
  transition: background var(--transition-base);
}
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-snow-white);
  position: absolute;
  left: 0;
  transition: transform var(--transition-base);
}
.nav-toggle-icon::before { top: -7px; }
.nav-toggle-icon::after { top: 7px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after { transform: translateY(-7px) rotate(-45deg); }

.primary-nav ul {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}
.primary-nav a {
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-primary);
  padding: 0.5rem 0;
  border-bottom: 2px solid transparent;
  transition: color var(--transition-base), border-color var(--transition-base);
}
.primary-nav a:hover,
.primary-nav a:focus-visible {
  color: var(--color-gold);
  border-bottom-color: var(--color-gold);
}
.primary-nav a[aria-current="page"] {
  color: var(--color-gold);
  border-bottom-color: var(--color-gold);
}

/* Footer */
.site-footer {
  background: var(--color-bg-dark);
  border-top: 1px solid var(--color-border-subtle);
  padding: 2.5rem 0 1rem;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 2rem;
}
.footer-left { flex: 1 1 300px; }
.footer-right { flex: 0 1 auto; }
.footer-brand {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--color-gold);
  margin-bottom: 0.5rem;
}
.footer-legal, .footer-contact {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
}
.footer-contact a { color: var(--color-gold); text-decoration: underline; }
.footer-links {
  display: flex;
  gap: 1.5rem;
}
.footer-links a {
  font-size: 0.85rem;
  color: var(--color-text-primary);
  border-bottom: 1px solid transparent;
  transition: color var(--transition-base), border-color var(--transition-base);
}
.footer-links a:hover { color: var(--color-gold); border-bottom-color: var(--color-gold); }
.footer-bottom {
  max-width: var(--max-width);
  margin: 1.5rem auto 0;
  padding: 1rem 1.5rem 0;
  border-top: 1px solid rgba(255,255,255,0.1);
  text-align: center;
}
.footer-slogan {
  font-family: var(--font-heading);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  letter-spacing: 0.1em;
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-gold);
  color: var(--color-bg-dark);
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  z-index: 900;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: opacity 0.3s, visibility 0.3s, transform 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}
.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.back-to-top:hover { background: var(--color-orange); color: var(--color-snow-white); }
.back-to-top:focus-visible { outline: 2px solid var(--color-snow-white); outline-offset: 2px; }

/* Generic Button */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.4rem;
  border: 2px solid var(--color-gold);
  background: transparent;
  color: var(--color-gold);
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
  transition: background var(--transition-base), color var(--transition-base);
}
.btn:hover { background: var(--color-gold); color: var(--color-bg-dark); }
.btn--gold { background: var(--color-gold); color: var(--color-bg-dark); }
.btn--gold:hover { background: var(--color-orange); border-color: var(--color-orange); }

/* Badge component */
.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2rem;
  height: 2rem;
  padding: 0 0.6rem;
  background: var(--color-card-bg);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border-subtle);
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  line-height: 1;
}
.badge--orange { background: var(--color-orange); color: var(--color-snow-white); border: none; }

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.75rem 0;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}
.breadcrumb a { color: var(--color-gold); transition: opacity var(--transition-base); }
.breadcrumb a:hover { opacity: 0.8; }
.breadcrumb [aria-current="page"] { color: var(--color-text-primary); }

/* Responsive */
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .primary-nav {
    position: absolute;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: rgba(10,22,40,0.98);
    backdrop-filter: blur(10px);
    padding: 0 1.5rem 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    border-bottom: 1px solid var(--color-border-subtle);
  }
  .primary-nav[data-open] {
    max-height: 600px;
    padding-bottom: 1.5rem;
  }
  .primary-nav ul {
    flex-direction: column;
    gap: 0.5rem;
    align-items: flex-start;
  }
  .primary-nav a {
    display: block;
    padding: 0.6rem 0;
    width: 100%;
    border-bottom: none;
  }
  .footer-inner { flex-direction: column; gap: 1.5rem; }
  .footer-links { flex-direction: column; gap: 0.8rem; }
  .back-to-top { bottom: 1rem; right: 1rem; width: 40px; height: 40px; font-size: 1.2rem; }
}

/* Tablet & up */
@media (min-width: 769px) {
  .primary-nav[data-open] { display: flex; }
}

/* Focus-visible */
:focus-visible { outline: 2px solid var(--color-gold); outline-offset: 2px; }

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}