/* ===== 基础与变量 ===== */
:root {
  --navy: #0A1B3D;
  --navy-2: #13295A;
  --gold: #D4AF37;
  --gold-soft: rgba(212, 175, 55, 0.55);
  --red: #E23B3B;
  --blue: #00D0FF;
  --purple: #7B61FF;
  --gray-light: #F2F4F7;
  --slate: #2D3748;
  --white: #FFFFFF;
  --font-heading: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", "Consolas", monospace;
  --radius: 16px;
  --radius-sm: 8px;
  --radius-pill: 999px;
  --content-width: 1200px;
  --content-pad: 28px;
  --transition: all 0.3s ease;
  --shadow-card: 0 1px 3px rgba(10, 27, 61, 0.06);
  --shadow-lift: 0 6px 20px rgba(10, 27, 61, 0.12);
}

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

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

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--slate);
  background-color: var(--gray-light);
  min-height: 100vh;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  color: inherit;
}

h1 { font-size: clamp(1.75rem, 4vw, 2.25rem); }
h2 { font-size: clamp(1.375rem, 3vw, 1.75rem); }
h3 { font-size: clamp(1.1rem, 2vw, 1.25rem); }

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

a:hover {
  color: var(--navy);
}

ul, ol {
  list-style: none;
}

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

button {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  border: none;
  background: none;
  cursor: pointer;
  color: inherit;
}

/* ===== 焦点与减少动效 ===== */
:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 4px;
}

@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;
  }
  html.js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ===== 通用布局 ===== */
.container {
  width: 100%;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--content-pad);
}

.section {
  padding: clamp(28px, 6vw, 56px) 0;
}

.section--tight {
  padding: 24px 0;
}

#main-content {
  scroll-margin-top: 120px;
}

.prose {
  max-width: 720px;
  margin: 0 auto;
}

.prose p {
  margin-bottom: 1.2em;
  line-height: 1.9;
}

.prose h2,
.prose h3 {
  margin-top: 1.8em;
  margin-bottom: 0.6em;
}

.prose ul {
  padding-left: 1.25em;
  margin-bottom: 1.2em;
  list-style: disc;
}

/* ===== 栅格 ===== */
.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
}

.col--span-3 { grid-column: span 3; }
.col--span-4 { grid-column: span 4; }
.col--span-5 { grid-column: span 5; }
.col--span-6 { grid-column: span 6; }
.col--span-7 { grid-column: span 7; }
.col--span-8 { grid-column: span 8; }
.col--span-9 { grid-column: span 9; }
.col--span-10 { grid-column: span 10; }
.col--span-11 { grid-column: span 11; }
.col--span-12 { grid-column: 1 / -1; }

@media (max-width: 860px) {
  .col--span-3,
  .col--span-4,
  .col--span-5,
  .col--span-6 {
    grid-column: span 6;
  }
  .col--span-7,
  .col--span-8,
  .col--span-9,
  .col--span-10,
  .col--span-11,
  .col--span-12 {
    grid-column: span 12;
  }
}

@media (max-width: 640px) {
  .grid {
    gap: 16px;
  }
  .col--span-3,
  .col--span-4,
  .col--span-5,
  .col--span-6,
  .col--span-7,
  .col--span-8,
  .col--span-9,
  .col--span-10,
  .col--span-11,
  .col--span-12 {
    grid-column: span 12;
  }
}

/* ===== 通用组件 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  background: var(--gold);
  color: var(--navy);
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 500;
  line-height: 1.4;
  text-decoration: none;
  transition: var(--transition);
}

.btn:hover {
  background: color-mix(in srgb, var(--gold) 85%, var(--white));
  color: var(--navy);
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(212, 175, 55, 0.3);
}

.btn:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
}

.btn--ghost {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.4);
  color: var(--white);
}

.btn--ghost:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--white);
  box-shadow: none;
}

.card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid #E8EBF2;
  color: var(--slate);
  box-shadow: var(--shadow-card);
  transition: var(--transition);
}

.card--interactive:hover {
  transform: translateY(-2px);
  border-color: var(--gold-soft);
  box-shadow: var(--shadow-lift);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0 0 24px;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: #8A93A6;
}

.breadcrumb a {
  color: var(--blue);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--navy);
  text-decoration: underline;
}

.breadcrumb .sep {
  color: #B6BDCC;
  margin: 0 4px;
}

.breadcrumb .current {
  color: var(--slate);
}

.img-frame {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  border-radius: var(--radius);
  background:
    linear-gradient(135deg, rgba(0, 208, 255, 0.10), transparent 60%),
    linear-gradient(45deg, rgba(123, 97, 255, 0.12), transparent 50%),
    var(--navy);
}

.img-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 24px 24px;
  pointer-events: none;
}

.img-frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ===== 跳过链接 ===== */
.skip-link {
  position: fixed;
  top: 16px;
  left: 16px;
  z-index: 9999;
  padding: 10px 20px;
  background: var(--gold);
  color: var(--navy);
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: var(--radius-pill);
  text-decoration: none;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.25);
  transform: translateY(-120px);
  transition: transform 0.3s ease;
}

.skip-link:focus {
  transform: translateY(0);
  color: var(--navy);
  outline: 2px solid var(--blue);
  outline-offset: 3px;
}

/* ===== 页头 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--navy);
  color: var(--white);
  border-bottom: 1px solid rgba(212, 175, 55, 0.2);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.18);
}

.site-header a {
  color: inherit;
}

.scroll-progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--gold), var(--blue));
  pointer-events: none;
  z-index: 3;
}

.masthead {
  position: relative;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 16px;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 16px var(--content-pad) 6px;
  overflow: hidden;
}

.masthead::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.025) 1px, transparent 1px);
  background-size: 36px 36px;
  pointer-events: none;
}

.masthead-side {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: rgba(255, 255, 255, 0.5);
}

.masthead-side--left {
  justify-content: flex-start;
}

.masthead-side--right {
  justify-content: flex-end;
}

.masthead-edition {
  color: rgba(255, 255, 255, 0.65);
  white-space: nowrap;
}

.masthead-edition::before {
  content: "[";
}

.masthead-edition::after {
  content: "]";
}

.masthead-center {
  position: relative;
  z-index: 1;
  text-align: center;
  min-width: 0;
}

.brand-link {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: inherit;
  text-decoration: none;
}

.brand-link:hover {
  color: inherit;
}

.brand-name {
  font-family: var(--font-heading);
  font-size: 1.9rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.16em;
  text-indent: 0.16em;
  color: var(--white);
  white-space: nowrap;
}

.brand-slogan {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.34em;
  text-indent: 0.34em;
  color: var(--gold);
  text-transform: uppercase;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.1);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: rgba(255, 255, 255, 0.7);
  white-space: nowrap;
}

.status-label {
  text-transform: uppercase;
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: var(--red);
  flex-shrink: 0;
}

.nav-section {
  position: relative;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 6px var(--content-pad) 10px;
}

.site-nav {
  position: relative;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.site-nav::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 15%;
  right: 15%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(212, 175, 55, 0.55), transparent);
  pointer-events: none;
}

.nav-list {
  display: flex;
  justify-content: center;
  align-items: stretch;
  gap: 2px;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9rem;
  text-decoration: none;
  position: relative;
  transition: var(--transition);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: -1px;
  height: 2px;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.nav-link:hover {
  color: var(--white);
  background: rgba(255, 255, 255, 0.04);
}

.nav-link:hover::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--gold);
}

.nav-index {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--blue);
  opacity: 0.65;
  transition: var(--transition);
}

.nav-link:hover .nav-index,
.nav-link[aria-current="page"] .nav-index {
  opacity: 1;
  color: var(--blue);
}

.nav-label {
  line-height: 1.2;
}

.nav-toggle {
  display: none;
  width: 100%;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 10px 16px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-pill);
  color: var(--white);
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: var(--transition);
}

.nav-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(212, 175, 55, 0.4);
}

.nav-toggle-text {
  font-family: var(--font-body);
  font-size: 0.9rem;
}

.nav-toggle-bars {
  position: relative;
  width: 16px;
  height: 2px;
  background: var(--gold);
  transition: var(--transition);
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--gold);
  transition: var(--transition);
}

.nav-toggle-bars::before {
  top: -5px;
}

.nav-toggle-bars::after {
  bottom: -5px;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bars {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after {
  bottom: 0;
  transform: rotate(-45deg);
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--navy);
  color: rgba(255, 255, 255, 0.75);
  position: relative;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(212, 175, 55, 0.7), rgba(0, 208, 255, 0.4), transparent);
  z-index: 1;
}

.site-footer a {
  color: inherit;
}

.footer-grid {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 44px var(--content-pad) 28px;
  display: grid;
  grid-template-columns: 1.5fr 0.8fr 1fr;
  gap: 44px;
}

.footer-brand,
.footer-links,
.footer-contact {
  min-width: 0;
}

.footer-brand .brand-name {
  font-size: 1.5rem;
}

.footer-brand .brand-slogan {
  font-size: 0.64rem;
}

.footer-trust {
  margin-top: 14px;
  font-size: 0.85rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.6);
  max-width: 320px;
}

.footer-heading {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--gold);
  text-transform: uppercase;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.footer-heading::before {
  content: "/";
  color: var(--blue);
  font-size: 0.9rem;
}

.footer-links-list,
.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links-list a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.7);
  text-decoration: none;
  transition: var(--transition);
}

.footer-links-list a::before {
  content: "→";
  font-family: var(--font-mono);
  color: var(--blue);
  font-size: 0.7rem;
  transition: transform 0.3s ease;
}

.footer-links-list a:hover {
  color: var(--gold);
  padding-left: 4px;
}

.footer-contact-list li {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: 6px;
  align-items: baseline;
}

.contact-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--blue);
  letter-spacing: 0.08em;
}

.contact-value {
  font-size: 0.88rem;
  color: rgba(255, 255, 255, 0.82);
  line-height: 1.6;
}

.footer-bottom {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 14px var(--content-pad) 26px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: rgba(255, 255, 255, 0.45);
}

.footer-copyright,
.footer-icp {
  margin: 0;
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 860px) {
  .masthead {
    padding: 12px 16px 6px;
    gap: 8px;
  }

  .brand-name {
    font-size: 1.5rem;
  }

  .brand-slogan {
    font-size: 0.58rem;
    letter-spacing: 0.2em;
    text-indent: 0.2em;
  }

  .masthead-side {
    font-size: 0.62rem;
  }

  .status-pill {
    padding: 2px 8px;
    font-size: 0.6rem;
  }

  .nav-toggle {
    display: flex;
    width: 100%;
  }

  .site-nav {
    display: none;
    border-top: none;
    border-bottom: none;
  }

  .site-nav[data-open] {
    display: block;
    padding-top: 8px;
  }

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

  .nav-link {
    padding: 12px 14px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  }

  .nav-link::after {
    left: 0;
    right: auto;
    top: 0;
    bottom: 0;
    width: 2px;
    height: auto;
    transform: scaleY(0);
    transform-origin: top;
  }

  .nav-link:hover::after,
  .nav-link[aria-current="page"]::after {
    transform: scaleY(1);
  }
}

@media (max-width: 640px) {
  :root {
    --content-pad: 16px;
  }
}

@media (max-width: 560px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 32px 16px 20px;
  }
  .footer-brand {
    grid-column: auto;
  }
  .footer-bottom {
    padding-left: 16px;
    padding-right: 16px;
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 420px) {
  .masthead {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .masthead-side--left {
    display: none;
  }

  .masthead-side--right {
    justify-content: center;
  }

  .masthead-center {
    justify-self: center;
  }
}

/* ===== 滚动显现与 JS 协议 ===== */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

html.js [data-reveal][data-visible] {
  opacity: 1;
  transform: none;
}