:root {
  --c-dark: #0A1D3A;
  --c-primary: #163A6B;
  --c-ocean: #1B5EBE;
  --c-orange: #FF6B35;
  --c-green: #39FF14;
  --c-white: #F4F6F9;
  --c-ink: #0D1B2A;
  --c-mist: #B8C7D9;
  --c-purple: #7B61FF;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Roboto Mono", "Cascadia Mono", Consolas, monospace;
  --header-h: 72px;
  --container-w: 1200px;
  --radius: 12px;
  --radius-sm: 6px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--c-ink);
  background: var(--c-white);
  padding-top: var(--header-h);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

img, svg, video, canvas {
  display: block;
  max-width: 100%;
  height: auto;
}

input, textarea, select, button {
  font: inherit;
  color: inherit;
}

button {
  background: none;
  border: none;
  cursor: pointer;
}

ul, ol {
  list-style: none;
}

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

h1, h2, h3, h4 {
  line-height: 1.2;
  font-weight: 800;
  color: var(--c-ink);
}

[hidden] {
  display: none !important;
}

/* ===== 容器与主体 ===== */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.main-content {
  display: block;
  min-height: 70vh;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 16px 0;
  font-size: 14px;
  color: var(--c-mist);
}
.breadcrumb a {
  color: var(--c-primary);
  transition: color 0.2s;
}
.breadcrumb a:hover {
  color: var(--c-orange);
}
.breadcrumb__sep {
  display: inline-block;
  color: var(--c-mist);
  font-family: var(--font-mono);
}

/* ===== 跳过链接 ===== */
.skip-link {
  position: fixed;
  top: -100px;
  left: 16px;
  z-index: 3000;
  display: inline-flex;
  align-items: center;
  padding: 12px 24px;
  background: var(--c-orange);
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  border-radius: 0 0 8px 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
  transition: top 0.3s ease;
}
.skip-link:focus {
  top: 0;
}

/* ===== 品牌 ===== */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: #fff;
}
.brand__logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--c-orange) 0%, #E55A2B 100%);
  color: #fff;
  font-weight: 900;
  font-size: 20px;
  line-height: 1;
  clip-path: polygon(0 0, 100% 0, 100% 72%, 72% 100%, 0 100%);
  transition: transform var(--transition);
  flex-shrink: 0;
}
.brand:hover .brand__logo {
  transform: rotate(-8deg) scale(1.05);
}
.brand__logo-text {
  transform: translate(-1px, -1px);
}
.brand__name {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0.04em;
  line-height: 1.2;
  white-space: nowrap;
}
.brand--footer .brand__logo {
  width: 44px;
  height: 44px;
  font-size: 22px;
}
.brand--footer .brand__name {
  color: #fff;
  font-size: 22px;
}

/* ===== 头部 ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 29, 58, 0.78);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(184, 199, 217, 0.1);
  transition: background 0.3s ease, box-shadow 0.3s ease;
}
.site-header--scrolled {
  background: rgba(10, 29, 58, 0.94);
  box-shadow: 0 10px 40px rgba(2, 8, 20, 0.4);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
}
.site-header__progress {
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 2;
  background: linear-gradient(90deg, var(--c-orange) 0%, var(--c-green) 55%, var(--c-ocean) 100%);
  transform: scaleX(0);
  transform-origin: left center;
  will-change: transform;
  pointer-events: none;
}

/* ===== 导航 ===== */
.site-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(20px, 2.2vw, 40px);
}
.site-nav a {
  position: relative;
  display: inline-block;
  padding: 8px 4px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.03em;
  color: rgba(244, 246, 249, 0.75);
  transition: color var(--transition);
}
.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--c-orange), var(--c-green));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}
.site-nav a:hover {
  color: #fff;
}
.site-nav a:hover::after,
.site-nav a[aria-current="page"]::after {
  transform: scaleX(1);
}
.site-nav a[aria-current="page"] {
  color: #fff;
}

/* ===== 移动端导航按钮 ===== */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  transition: background var(--transition);
}
.nav-toggle:hover {
  background: rgba(255, 255, 255, 0.16);
}
.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* ===== 页脚 ===== */
.site-footer {
  background: linear-gradient(180deg, var(--c-dark) 0%, #060F20 100%);
  color: var(--c-mist);
  position: relative;
  overflow: hidden;
}
.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--c-orange) 0%, var(--c-green) 50%, var(--c-ocean) 100%);
  opacity: 0.7;
  pointer-events: none;
}
.site-footer__grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 0.8fr;
  gap: 48px;
  padding: 64px 0 48px;
}
.site-footer__brand-col .site-footer__desc {
  max-width: 340px;
  margin-top: 16px;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(184, 199, 217, 0.75);
}
.site-footer__title {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #fff;
  margin-bottom: 18px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(184, 199, 217, 0.15);
  position: relative;
}
.site-footer__title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 32px;
  height: 2px;
  background: var(--c-green);
}
.site-footer__list {
  display: grid;
  gap: 10px;
  font-size: 14px;
  line-height: 1.6;
  color: rgba(184, 199, 217, 0.85);
}
.site-footer__links {
  display: grid;
  gap: 2px;
}
.site-footer__links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 0;
  font-size: 14px;
  color: rgba(184, 199, 217, 0.85);
  transition: color 0.25s ease, padding-left 0.25s ease;
}
.site-footer__links a::before {
  content: "→";
  font-family: var(--font-mono);
  color: var(--c-orange);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.25s, transform 0.25s;
}
.site-footer__links a:hover {
  color: var(--c-green);
  padding-left: 12px;
}
.site-footer__links a:hover::before {
  opacity: 1;
  transform: translateX(0);
}
.site-footer__bottom {
  border-top: 1px solid rgba(184, 199, 217, 0.12);
  padding: 20px 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  font-size: 13px;
  font-family: var(--font-mono);
  color: rgba(184, 199, 217, 0.6);
}

/* ===== 通用组件 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 16px;
  font-weight: 600;
  line-height: 1;
  border-radius: 8px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.25s ease, color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease, border-color 0.25s ease;
}
.btn--primary {
  background: var(--c-orange);
  color: #fff;
  box-shadow: 0 4px 16px rgba(255, 107, 53, 0.3);
}
.btn--primary:hover {
  background: #E85B26;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(255, 107, 53, 0.4);
}
.btn--ghost {
  border: 1px solid rgba(184, 199, 217, 0.4);
  color: var(--c-ink);
  background: transparent;
}
.btn--ghost:hover {
  border-color: var(--c-ocean);
  color: var(--c-ocean);
  transform: translateY(-2px);
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-ocean);
}
.section-label::before {
  content: "";
  width: 28px;
  height: 2px;
  background: var(--c-orange);
  flex-shrink: 0;
}

.data-num {
  font-family: var(--font-mono);
  font-size: 1.15em;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.03em;
}

.glass-card {
  position: relative;
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.glass-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 40px rgba(10, 29, 58, 0.2);
}

.img-placeholder {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 220px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--c-primary) 0%, var(--c-dark) 100%);
  color: var(--c-mist);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.05em;
  overflow: hidden;
}
.img-placeholder::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 20% 20%, rgba(57, 255, 20, 0.08), transparent 50%),
              radial-gradient(circle at 80% 80%, rgba(255, 107, 53, 0.08), transparent 50%);
  pointer-events: none;
}
.img-placeholder::after {
  content: attr(data-label);
  position: relative;
  z-index: 1;
  padding: 8px 16px;
  border: 1px solid rgba(184, 199, 217, 0.25);
  border-radius: 6px;
  background: rgba(10, 29, 58, 0.4);
  color: rgba(244, 246, 249, 0.9);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ===== 响应式 ===== */
@media (max-width: 991px) {
  .site-nav__list {
    gap: 16px;
  }
  .site-nav a {
    font-size: 14px;
    padding: 6px 2px;
  }
  .site-footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 767px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
  body {
    font-size: 15px;
  }
  .nav-toggle {
    display: inline-flex;
  }
  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    z-index: 999;
    background: rgba(10, 29, 58, 0.97);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    padding: 24px 16px;
    border-bottom: 1px solid rgba(184, 199, 217, 0.15);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-12px);
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s;
  }
  .site-nav[data-open] {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
  }
  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }
  .site-nav__list a {
    display: block;
    padding: 14px 8px;
    font-size: 18px;
    border-bottom: 1px solid rgba(184, 199, 217, 0.08);
  }
  .site-nav__list a::after {
    display: none;
  }
  .site-nav__list a[aria-current="page"] {
    color: var(--c-green);
  }
  .site-header__inner {
    height: 64px;
  }
  :root {
    --header-h: 64px;
  }
  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding: 48px 0 32px;
  }
  .site-footer__bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }
  .breadcrumb {
    padding: 12px 0;
    font-size: 13px;
  }
  .btn {
    padding: 11px 20px;
    font-size: 15px;
  }
  .img-placeholder {
    min-height: 160px;
  }
}

/* ===== 无障碍与动效偏好 ===== */
:focus-visible {
  outline: 3px solid var(--c-orange);
  outline-offset: 2px;
  border-radius: 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;
  }
  .site-header,
  .site-header__progress,
  .nav-toggle__bar,
  .glass-card,
  .btn,
  .brand__logo {
    transition: none !important;
  }
}