:root {
  --c-primary: #0A1F44;
  --c-card: #122A5C;
  --c-surface: #1B3A6B;
  --c-line: #2A4A7F;
  --c-text: #E5E9F0;
  --c-muted: #A9B4C8;
  --c-accent: #F2B705;
  --c-gold: #FFD75E;
  --c-red: #E63946;
  --c-deep: #081233;

  --f-display: 'Anton', 'Impact', 'Arial Black', sans-serif;
  --f-body: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --f-mono: 'JetBrains Mono', 'Courier New', monospace;

  --fs-display: clamp(2.8rem, 8vw, 6rem);
  --fs-h1: clamp(2.2rem, 5vw, 4rem);
  --fs-h2: clamp(1.6rem, 3.5vw, 2.6rem);
  --fs-h3: 1.4rem;
  --fs-base: 1rem;
  --fs-sm: 0.875rem;
  --fs-xs: 0.75rem;

  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 1rem;
  --sp-4: 1.5rem;
  --sp-5: 2rem;
  --sp-6: 3rem;
  --sp-7: 4rem;
  --sp-8: 5rem;

  --r-sm: 4px;
  --r-md: 10px;
  --r-lg: 18px;
  --r-pill: 999px;

  --w-container: 1280px;
  --w-prose: 68ch;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --dur: 0.3s;
}

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

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

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  font-family: var(--f-body);
  font-size: var(--fs-base);
  line-height: 1.7;
  color: var(--c-text);
  background-color: var(--c-primary);
  background-image:
    radial-gradient(ellipse at 22% -5%, rgba(27, 58, 107, 0.55) 0%, transparent 55%),
    radial-gradient(ellipse at 95% 15%, rgba(242, 183, 5, 0.04) 0%, transparent 35%);
  overflow-x: hidden;
}

.main-content {
  flex: 1;
  width: 100%;
  padding-top: 7rem;
}

#main-content:focus {
  outline: none;
}

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

a {
  color: var(--c-accent);
}

button {
  font: inherit;
}

ul[class],
ol[class] {
  list-style: none;
}

.container {
  width: 100%;
  max-width: var(--w-container);
  margin-inline: auto;
  padding-inline: var(--sp-4);
}

.text-muted {
  color: var(--c-muted);
}

:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 3px;
}

::selection {
  background: rgba(242, 183, 5, 0.3);
}

/* ---------- 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.5rem;
  border: none;
  border-radius: var(--r-pill);
  font-family: var(--f-body);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  white-space: nowrap;
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.btn-primary {
  background: linear-gradient(135deg, var(--c-accent) 0%, var(--c-gold) 100%);
  color: var(--c-primary);
  box-shadow: 0 4px 18px rgba(242, 183, 5, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(242, 183, 5, 0.42);
}

/* ---------- 悬浮导航 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 200;
  padding: 1rem 1.25rem 0;
  pointer-events: none;
}

.nav-shell {
  position: relative;
  max-width: var(--w-container);
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 0.5rem 0.5rem 1.25rem;
  background: linear-gradient(to bottom, rgba(27, 58, 107, 0.92), rgba(13, 31, 68, 0.9));
  border: 1px solid rgba(42, 74, 127, 0.6);
  border-radius: var(--r-pill);
  box-shadow: 0 12px 48px rgba(4, 10, 25, 0.5);
  pointer-events: auto;
}

.nav-shell::after {
  content: '';
  position: absolute;
  left: 1.5rem;
  right: 1rem;
  bottom: 3px;
  height: 1px;
  background: linear-gradient(to right, var(--c-accent), rgba(242, 183, 5, 0.2) 30%, rgba(230, 57, 70, 0.3) 80%, transparent);
  opacity: 0.7;
  border-radius: 2px;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(to right, var(--c-accent), var(--c-red));
  z-index: 300;
  transition: width 0.2s var(--ease);
}

/* ---------- 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: -120px;
  left: 1.25rem;
  z-index: 400;
  padding: 0.75rem 1.5rem;
  background: var(--c-accent);
  color: var(--c-primary);
  font-weight: 700;
  border-radius: var(--r-sm);
  text-decoration: none;
  box-shadow: 0 4px 20px rgba(242, 183, 5, 0.4);
  transition: top var(--dur) var(--ease);
}

.skip-link:focus {
  top: 1rem;
}

/* ---------- 品牌 ---------- */
.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--c-text);
  flex-shrink: 0;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.1em;
  height: 2.1em;
  padding: 0 0.35em;
  font-family: var(--f-display);
  font-size: 1.15rem;
  font-weight: 900;
  color: var(--c-primary);
  background: linear-gradient(135deg, var(--c-accent), var(--c-gold));
  border-radius: 6px;
  transform: skewX(-10deg);
  box-shadow: 0 3px 14px rgba(242, 183, 5, 0.35);
}

.brand-text {
  font-family: var(--f-display);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--c-text);
  line-height: 1.2;
  white-space: nowrap;
}

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

/* ---------- 主导航 ---------- */
.main-nav {
  flex: 1;
  display: flex;
  justify-content: center;
  margin-inline: 0.25rem;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  margin: 0;
  padding: 0;
}

.nav-link {
  position: relative;
  display: block;
  padding: 0.45rem 0.9rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--c-text);
  text-decoration: none;
  border-radius: var(--r-pill);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.nav-link:hover {
  color: var(--c-gold);
  background: rgba(42, 74, 127, 0.3);
}

.nav-link[aria-current="page"] {
  color: var(--c-accent);
  background: rgba(242, 183, 5, 0.12);
}

.nav-link[aria-current="page"]::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c-accent);
}

.nav-cta {
  flex-shrink: 0;
}

/* ---------- 汉堡按钮 ---------- */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid var(--c-line);
  border-radius: 50%;
  cursor: pointer;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.nav-toggle:hover {
  border-color: var(--c-accent);
}

.nav-toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--c-text);
  border-radius: 2px;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease), background var(--dur) var(--ease);
}

.nav-toggle:hover .nav-toggle-bar {
  background: var(--c-accent);
}

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

/* ---------- 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: var(--sp-8);
  background: var(--c-deep);
  color: var(--c-text);
  overflow: hidden;
}

.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(to right, var(--c-accent) 0%, var(--c-red) 22%, transparent 65%);
  z-index: 2;
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(200px, 0.8fr) minmax(280px, 1.2fr);
  gap: 3rem;
  max-width: var(--w-container);
  margin-inline: auto;
  padding: var(--sp-7) var(--sp-4) var(--sp-6);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--f-display);
  font-size: 1.5rem;
  font-weight: 900;
  letter-spacing: 0.04em;
  color: var(--c-text);
  text-transform: uppercase;
}

.footer-logo .brand-mark {
  font-size: 1rem;
  min-width: 2em;
  height: 2em;
}

.footer-logo-text {
  color: var(--c-text);
}

.footer-desc {
  color: var(--c-muted);
  font-size: var(--fs-sm);
  line-height: 1.8;
  max-width: 34ch;
}

.footer-slogan {
  font-family: var(--f-mono);
  font-size: var(--fs-xs);
  color: var(--c-accent);
  letter-spacing: 0.1em;
  padding-top: 1rem;
  border-top: 1px solid rgba(42, 74, 127, 0.5);
}

.footer-col {
  padding-top: 0.1rem;
}

.footer-heading {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  font-family: var(--f-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--c-text);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.footer-num {
  font-family: var(--f-mono);
  font-size: 0.75rem;
  color: var(--c-accent);
  background: rgba(242, 183, 5, 0.1);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.55rem;
}

.footer-links a {
  position: relative;
  padding-left: 1.25rem;
  color: var(--c-muted);
  text-decoration: none;
  font-size: var(--fs-sm);
  transition: color var(--dur) var(--ease);
}

.footer-links a::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  width: 10px;
  height: 1px;
  background: var(--c-accent);
  transform: skewX(-14deg);
}

.footer-links a:hover {
  color: var(--c-gold);
}

.footer-contact {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.7rem;
}

.footer-contact li {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  font-size: var(--fs-sm);
  color: var(--c-muted);
  line-height: 1.6;
}

.footer-contact-label {
  flex-shrink: 0;
  min-width: 3em;
  font-family: var(--f-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.05em;
  color: var(--c-accent);
  text-transform: uppercase;
}

.footer-msg {
  margin-top: 1.25rem;
  font-size: var(--fs-sm);
  color: var(--c-muted);
  line-height: 1.7;
  border-left: 2px solid var(--c-accent);
  padding-left: 0.9rem;
}

.footer-bottom {
  border-top: 1px solid rgba(42, 74, 127, 0.4);
}

.footer-bottom-inner {
  max-width: var(--w-container);
  margin-inline: auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 1.4rem var(--sp-4) 2rem;
}

.footer-legal {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: var(--fs-sm);
}

.footer-legal a {
  color: var(--c-muted);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.footer-legal a:hover {
  color: var(--c-accent);
}

.footer-sep {
  color: var(--c-line);
}

.footer-copy {
  font-family: var(--f-mono);
  font-size: var(--fs-sm);
  color: var(--c-muted);
}

/* ---------- 返回顶部 ---------- */
.back-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 150;
  width: 46px;
  height: 46px;
  background: linear-gradient(135deg, var(--c-accent), var(--c-gold));
  color: var(--c-primary);
  border: none;
  border-radius: 50%;
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 6px 24px rgba(242, 183, 5, 0.35);
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease), visibility var(--dur), box-shadow var(--dur) var(--ease);
}

.back-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-top:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 32px rgba(242, 183, 5, 0.5);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0 0 2rem;
  padding: 0;
  list-style: none;
  font-size: var(--fs-sm);
  color: var(--c-muted);
}

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

.breadcrumb li + li::before {
  content: '/';
  margin-right: 0.5rem;
  color: var(--c-line);
}

.breadcrumb a {
  color: var(--c-muted);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.breadcrumb a:hover {
  color: var(--c-accent);
}

.breadcrumb [aria-current="page"] {
  color: var(--c-text);
}

/* ---------- 排版 ---------- */
.page-title {
  font-family: var(--f-display);
  font-size: var(--fs-h1);
  font-weight: 900;
  line-height: 1.08;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--c-text);
  margin: 0 0 var(--sp-4);
}

.page-title::after {
  content: '';
  display: block;
  width: 88px;
  height: 3px;
  margin-top: var(--sp-3);
  background: linear-gradient(to right, var(--c-accent), transparent);
  border-radius: 2px;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--f-mono);
  font-size: var(--fs-sm);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--c-accent);
}

.section-label::before {
  content: '';
  width: 26px;
  height: 2px;
  background: var(--c-accent);
  transform: skewX(-16deg);
}

.prose {
  max-width: var(--w-prose);
  line-height: 1.85;
  color: var(--c-muted);
}

.prose p {
  margin-bottom: 1.5rem;
}

.prose h2,
.prose h3 {
  font-family: var(--f-display);
  font-weight: 700;
  color: var(--c-text);
  line-height: 1.25;
  margin: 2.5rem 0 0.75rem;
}

.prose a {
  color: var(--c-accent);
}

.section {
  padding-block: var(--sp-7);
}

/* ---------- 网格 ---------- */
.grid {
  display: grid;
  gap: 2rem;
}

.grid--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid--4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* ---------- 卡片 ---------- */
.card {
  background: var(--c-card);
  border: 1px solid var(--c-line);
  border-radius: var(--r-lg);
  padding: var(--sp-5);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(242, 183, 5, 0.35);
  box-shadow: 0 16px 36px rgba(4, 10, 25, 0.4);
}

/* ---------- 图片占位容器 ---------- */
.img-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  border-radius: var(--r-md);
  border: 1px solid var(--c-line);
  background:
    repeating-linear-gradient(-45deg, rgba(255, 255, 255, 0.02) 0 8px, transparent 8px 16px),
    linear-gradient(160deg, var(--c-card) 0%, var(--c-primary) 100%);
  overflow: hidden;
}

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

.img-frame--portrait {
  aspect-ratio: 3 / 4;
}

.img-frame::before {
  content: attr(data-label);
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 0.5em 1.25em;
  font-family: var(--f-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--c-muted);
  background: rgba(10, 31, 68, 0.55);
  border: 1px solid var(--c-line);
  border-radius: var(--r-pill);
  white-space: nowrap;
}

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .main-content {
    padding-top: 6.5rem;
  }

  .grid--4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .grid--3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-top {
    grid-template-columns: 1.4fr 1fr;
    gap: 2.5rem;
  }

  .footer-col:last-child {
    grid-column: span 2;
  }
}

@media (max-width: 920px) {
  .site-header {
    padding: 0.75rem 1rem 0;
  }

  .nav-shell {
    padding: 0.4rem 0.4rem 0.4rem 1rem;
  }

  .brand-text {
    font-size: 1rem;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .main-nav {
    position: fixed;
    top: calc(4.5rem + 12px);
    right: 1rem;
    left: 1rem;
    flex: initial;
    display: block;
    margin-inline: 0;
    padding: 0.5rem;
    max-height: calc(100vh - 6rem);
    overflow-y: auto;
    background: rgba(14, 30, 66, 0.97);
    border: 1px solid var(--c-line);
    border-radius: var(--r-lg);
    box-shadow: 0 24px 64px rgba(4, 10, 25, 0.55);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0s linear 0.25s;
    z-index: 210;
  }

  .main-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0s;
  }

  .main-nav::before {
    content: '';
    position: absolute;
    top: -6px;
    right: 24px;
    width: 12px;
    height: 12px;
    background: var(--c-deep);
    border-top: 1px solid var(--c-line);
    border-left: 1px solid var(--c-line);
    transform: rotate(45deg);
    z-index: -1;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
  }

  .nav-link {
    padding: 0.8rem 1.25rem;
    font-size: 1rem;
  }

  .nav-link[aria-current="page"]::after {
    right: 1.25rem;
    left: auto;
    bottom: 50%;
    transform: none;
    margin-bottom: -3px;
  }
}

@media (max-width: 640px) {
  .site-header {
    padding-inline: 0.75rem;
  }

  .nav-shell {
    gap: 0.4rem;
  }

  .brand-text {
    font-size: 0.9rem;
  }

  .brand-mark {
    font-size: 0.95rem;
  }

  .nav-cta {
    padding: 0.5rem 0.9rem;
    font-size: 0.88rem;
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: var(--sp-6) var(--sp-4);
  }

  .footer-col:last-child {
    grid-column: auto;
  }

  .footer-bottom-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .back-top {
    bottom: 1rem;
    right: 1rem;
  }

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

/* ---------- 减少动态效果 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }

  .scroll-progress {
    transition: none;
  }

  .main-nav,
  .main-nav[data-open="true"] {
    transition: none;
  }
}