/* ============ RESET & BASE ============ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  font-family: 'Noto Sans SC', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  font-size: 16px;
  line-height: 1.75;
  color: #1B2A36;
  background-color: #F3F9FC;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

#main-content {
  flex: 1 0 auto;
}

/* ============ CSS VARIABLES ============ */
:root {
  --color-primary: #0A5C8A;
  --color-primary-light: #1A7FB5;
  --color-secondary: #FF7A45;
  --color-accent: #F5C96B;
  --color-bg: #F3F9FC;
  --color-surface: #FFFFFF;
  --color-text: #1B2A36;
  --color-muted: #5A6B7A;
  --color-success: #2E8B57;
  --color-warning: #D4A017;

  --font-heading: 'Unbounded', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Noto Sans SC', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-data: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Courier New', monospace;

  --radius-xs: 6px;
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-pill: 999px;

  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 40px;
  --space-2xl: 64px;

  --content-max: 1200px;
  --header-topbar-h: 46px;
  --header-navbar-h: 48px;

  --shadow-sm: 0 2px 8px rgba(27, 42, 54, 0.06);
  --shadow-md: 0 8px 24px rgba(27, 42, 54, 0.08);
  --shadow-lg: 0 16px 40px rgba(10, 92, 138, 0.14);

  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
}

/* ============ TYPOGRAPHY ============ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 900;
  line-height: 1.2;
  color: var(--color-text);
  margin: 0 0 0.6em;
}

h1 { font-size: 36px; }
h2 { font-size: 28px; }
h3 { font-size: 20px; }
h4 { font-size: 16px; }

p {
  margin: 0 0 1em;
}

strong {
  font-weight: 700;
}

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

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

/* ============ LAYOUT ============ */
.container,
.header-shell,
.footer-shell {
  width: min(100% - 48px, var(--content-max));
  margin-inline: auto;
}

.section {
  padding-block: var(--space-xl);
}

.section-sm {
  padding-block: var(--space-lg);
}

[hidden] {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
  white-space: nowrap;
}

.text-center { text-align: center; }
.text-muted { color: var(--color-muted); }
.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: var(--space-md); }
.mb-4 { margin-bottom: var(--space-xl); }

/* ============ BUTTONS ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-pill);
  border: 2px solid transparent;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.2;
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-light);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 8px 20px rgba(10, 92, 138, 0.25);
}

.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-secondary:hover {
  background: rgba(10, 92, 138, 0.08);
  color: var(--color-primary);
}

.btn-orange {
  background: var(--color-secondary);
  color: #fff;
}

.btn-orange:hover {
  background: #FF6A30;
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 8px 20px rgba(255, 122, 69, 0.3);
}

.filter-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(10, 92, 138, 0.2);
  background: var(--color-surface);
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.filter-btn:hover {
  border-color: var(--color-primary-light);
  color: var(--color-primary);
}

.filter-btn.is-active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

/* ============ BREADCRUMB ============ */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  padding: 0;
  margin: 0 0 var(--space-lg);
  font-size: 14px;
  color: var(--color-muted);
}

.breadcrumb li {
  display: flex;
  align-items: center;
}

.breadcrumb li + li::before {
  content: '/';
  margin-right: 8px;
  color: rgba(10, 92, 138, 0.35);
}

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

.breadcrumb a:hover {
  text-decoration: underline;
}

/* ============ CARDS & GRID ============ */
.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border: 1px solid rgba(10, 92, 138, 0.08);
  box-shadow: var(--shadow-sm);
}

.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

/* ============ IMAGES ============ */
.image-frame {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: linear-gradient(135deg, rgba(10, 92, 138, 0.08), rgba(245, 201, 107, 0.15));
}

.image-frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-frame--wide {
  aspect-ratio: 16 / 9;
}

.image-frame--square {
  aspect-ratio: 1 / 1;
}

.image-frame--standard {
  aspect-ratio: 4 / 3;
}

.image-caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 8px 16px;
  font-size: 13px;
  color: #fff;
  background: linear-gradient(to top, rgba(5, 44, 68, 0.55), transparent);
}

.image-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 220px;
  padding: var(--space-lg);
  border-radius: var(--radius-lg);
  border: 1.5px dashed rgba(10, 92, 138, 0.2);
  background: linear-gradient(135deg, rgba(10, 92, 138, 0.04), rgba(245, 201, 107, 0.1));
  color: var(--color-muted);
  font-size: 14px;
  text-align: center;
}

/* ============ HEADER ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(243, 249, 252, 0.88);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(10, 92, 138, 0.12);
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-secondary) 60%, var(--color-accent) 100%);
  z-index: 300;
  pointer-events: none;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 200;
  padding: 10px 20px;
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 14px;
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 12px;
}

.header-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: var(--header-topbar-h);
  position: relative;
  z-index: 2;
}

/* Brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--color-text);
  text-decoration: none;
  flex-shrink: 0;
}

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

.brand-badge {
  width: 36px;
  height: 36px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(10, 92, 138, 0.25);
}

.brand-badge svg {
  display: block;
}

.brand-text {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 20px;
  letter-spacing: 0.02em;
  line-height: 1.2;
  color: var(--color-primary);
}

.brand-text::after {
  content: '';
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-left: 5px;
  border-radius: 50%;
  background: var(--color-secondary);
  vertical-align: middle;
  position: relative;
  top: -1px;
}

/* Header actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.version-switcher {
  display: inline-flex;
  align-items: center;
  padding: 3px;
  background: rgba(10, 92, 138, 0.1);
  border-radius: var(--radius-pill);
}

.version-chip {
  padding: 5px 12px;
  border: none;
  background: transparent;
  border-radius: var(--radius-pill);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  color: var(--color-muted);
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast);
}

.version-chip:hover {
  color: var(--color-primary);
}

.version-chip.is-active {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(10, 92, 138, 0.3);
}

/* Nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  padding: 0;
  border: none;
  background: transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  color: var(--color-primary);
  transition: background var(--transition-fast);
}

.nav-toggle:hover {
  background: rgba(10, 92, 138, 0.08);
}

.nav-toggle-box {
  display: flex;
  flex-direction: column;
  gap: 5px;
  width: 20px;
}

.nav-toggle-line {
  display: block;
  height: 2px;
  width: 100%;
  background: currentColor;
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Header navbar */
.header-navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: var(--header-navbar-h);
  position: relative;
  z-index: 1;
  border-top: 1px solid rgba(10, 92, 138, 0.06);
}

/* ============ NAVIGATION ============ */
.site-nav {
  flex: 1;
}

.nav-list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0;
  margin: 0;
}

.nav-item {
  margin: 0;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  font-size: 14px;
  font-weight: 500;
  color: var(--color-muted);
  text-decoration: none;
  white-space: nowrap;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.nav-link:hover {
  background: rgba(10, 92, 138, 0.08);
  color: var(--color-primary);
}

.nav-link[aria-current="page"] {
  background: var(--color-primary);
  color: #fff;
  font-weight: 700;
}

/* ============ SEARCH ============ */
.search-box {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  border: 1px solid rgba(10, 92, 138, 0.14);
  color: var(--color-muted);
  flex-shrink: 0;
  cursor: text;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-box:focus-within {
  border-color: var(--color-primary-light);
  box-shadow: 0 0 0 4px rgba(26, 127, 181, 0.12);
}

.search-symbol {
  display: inline-flex;
  color: inherit;
}

.search-symbol svg {
  display: block;
}

.search-input {
  -webkit-appearance: none;
  appearance: none;
  border: none;
  background: transparent;
  width: 160px;
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--color-text);
  outline: none;
}

.search-input::placeholder {
  color: var(--color-muted);
  opacity: 0.7;
}

.search-input::-webkit-search-cancel-button {
  -webkit-appearance: none;
  appearance: none;
}

/* ============ MOBILE NAV ============ */
@media (max-width: 767px) {
  .nav-toggle {
    display: inline-flex;
  }

  .header-navbar {
    position: absolute;
    top: 100%;
    left: var(--space-md);
    right: var(--space-md);
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    min-height: auto;
    padding: var(--space-sm);
    background: var(--color-surface);
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border-top: none;
  }

  .header-navbar[data-open] {
    display: flex;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
  }

  .nav-link {
    display: block;
    width: 100%;
    padding: 12px 16px;
    font-size: 15px;
  }

  .search-box {
    margin-top: 12px;
    padding: 10px 16px;
  }

  .search-input {
    width: 100%;
  }
}

/* ============ FOOTER ============ */
.site-footer {
  position: relative;
  margin-top: var(--space-2xl);
  background: linear-gradient(135deg, #052C44 0%, #0A5C8A 55%, #1A7FB5 100%);
  color: rgba(255, 255, 255, 0.85);
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  overflow: hidden;
  padding-top: var(--space-xl);
}

.site-footer::before {
  content: '';
  position: absolute;
  top: -40px;
  left: 15%;
  width: 240px;
  height: 140px;
  background: radial-gradient(ellipse, rgba(255, 122, 69, 0.12), transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.footer-shell {
  padding-bottom: var(--space-lg);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1.3fr 0.9fr;
  gap: 32px;
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.footer-brand .footer-logo {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 20px;
  color: #fff;
  text-decoration: none;
}

.footer-logo:hover {
  color: #fff;
}

.footer-logo::after {
  content: '';
  display: inline-block;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--color-secondary);
  margin-left: 4px;
}

.footer-tagline {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 15px;
  color: var(--color-accent);
  margin: 12px 0 8px;
  padding-left: 12px;
  border-left: 3px solid var(--color-secondary);
  line-height: 1.4;
}

.footer-desc {
  font-size: 14px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.7);
  max-width: 320px;
  margin: 0;
}

.footer-col .footer-title {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 16px;
}

.footer-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-list li {
  margin: 0 0 8px;
}

.footer-list a {
  color: rgba(255, 255, 255, 0.75);
  font-size: 14px;
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.footer-list a:hover {
  color: #fff;
  padding-left: 4px;
}

.footer-contact-list .contact-label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: rgba(255, 255, 255, 0.5);
}

.footer-contact-list .contact-value {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.85);
  word-break: break-word;
}

.footer-contact-list .contact-value.is-data {
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: 0.02em;
}

.footer-contact-list li + li {
  margin-top: 12px;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 20px 0 0;
  text-align: center;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.6);
  padding-bottom: 20px;
  padding-bottom: calc(20px + env(safe-area-inset-bottom));
}

.footer-copy,
.footer-icp,
.footer-trust {
  margin: 0;
}

/* ============ RESPONSIVE ============ */
@media (max-width: 1023px) and (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 767px) {
  .container,
  .header-shell,
  .footer-shell {
    width: min(100% - 32px, var(--content-max));
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: 1fr;
  }

  .version-switcher {
    padding: 2px;
  }

  .version-chip {
    padding: 4px 10px;
    font-size: 12px;
  }

  .brand-text {
    font-size: 17px;
  }

  .brand-text::after {
    width: 4px;
    height: 4px;
    margin-left: 4px;
  }

  .brand-badge {
    width: 32px;
    height: 32px;
    border-radius: 10px;
  }

  .header-actions {
    gap: 8px;
  }

  .header-topbar {
    gap: 8px;
  }
}

/* ============ ACCESSIBILITY ============ */
:focus-visible {
  outline: 3px solid rgba(255, 122, 69, 0.6);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}