:root {
  --paper: #F5F0E8;
  --paper-deep: #ECE5D8;
  --ink: #10243E;
  --ink-light: #1C3A5E;
  --neon: #C8F04A;
  --orange: #FF8A3C;
  --silver: #C9D2DE;
  --white: #FFFFFF;
  --muted: #5F738C;
  --deep-blue: #0B1B2E;
  --light-blue: #E2ECF5;
  --font-body: "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, monospace;
  --radius: 6px;
  --shadow-card: 0 2px 8px rgba(11, 27, 46, 0.06);
  --shadow-card-hover: 0 10px 26px rgba(11, 27, 46, 0.12);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  background: var(--paper);
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
}

main {
  display: block;
}

#main-content {
  display: block;
  scroll-margin-top: 16px;
  min-height: 50vh;
}

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

a {
  color: var(--ink-light);
}

p {
  margin: 0 0 1em;
}

h1,
h2,
h3,
h4 {
  margin: 0 0 0.6em;
  font-weight: 800;
  line-height: 1.25;
  color: var(--ink);
}

ul,
ol {
  margin: 0 0 1em 1.4em;
  padding: 0;
}

::selection {
  background: var(--neon);
  color: var(--ink);
}

:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 2px;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.container-narrow {
  max-width: 840px;
}

.skip-link {
  position: fixed;
  top: -80px;
  left: 16px;
  z-index: 1200;
  background: var(--ink);
  color: var(--neon);
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 700;
  border-radius: 0 0 6px 6px;
  box-shadow: 0 4px 12px rgba(11, 27, 46, 0.25);
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
  outline: 2px solid var(--orange);
  outline-offset: 0;
}

.site-header {
  position: relative;
  z-index: 100;
  background: var(--paper);
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 1100;
  pointer-events: none;
  background: rgba(16, 36, 62, 0.06);
}

.scroll-progress-bar {
  display: block;
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--neon), var(--orange));
  transform-origin: 0 50%;
  transition: width 0.08s linear;
}

.header-cn {
  position: relative;
  background: var(--deep-blue);
  color: var(--silver);
  border-bottom: 1px solid rgba(201, 210, 222, 0.14);
  overflow: hidden;
}

.header-cn::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(135deg, rgba(201, 210, 222, 0.05) 0 6px, transparent 6px 12px);
  pointer-events: none;
}

.header-cn-inner {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 38px;
  padding-top: 4px;
  padding-bottom: 4px;
}

.header-cn-index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--silver);
}

.header-cn-text {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--silver);
}

.header-cn-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--neon);
}

.header-cn-tag::before {
  content: "";
  width: 8px;
  height: 8px;
  background: var(--neon);
  transform: rotate(45deg);
  box-shadow: 0 0 8px rgba(200, 240, 74, 0.6);
}

.header-main {
  position: relative;
  background: var(--white);
  border-bottom: 1px solid var(--silver);
  box-shadow: 0 1px 0 rgba(16, 36, 62, 0.03), 0 2px 12px rgba(16, 36, 62, 0.04);
}

.header-main::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 96px;
  height: 2px;
  background: var(--orange);
  z-index: 1;
}

.header-main-inner {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 76px;
}

.header-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  text-decoration: none;
  color: var(--ink);
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--ink);
  color: var(--neon);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 800;
  padding: 7px 9px;
  letter-spacing: 0.08em;
  clip-path: polygon(0 0, 100% 0, 100% 68%, 76% 100%, 0 100%);
}

.brand-name {
  font-size: 24px;
  font-weight: 900;
  letter-spacing: 0.08em;
  line-height: 1.1;
  white-space: nowrap;
}

.brand-name::after {
  content: "/";
  font-family: var(--font-mono);
  color: var(--orange);
  font-weight: 400;
  margin-left: 3px;
}

.brand-descriptor {
  display: none;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--muted);
  border-left: 1px solid var(--silver);
  padding-left: 12px;
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  position: relative;
  z-index: 2;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border: 1px solid var(--silver);
  border-radius: 4px;
  background: var(--white);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease;
}

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

.nav-toggle[aria-expanded="true"] {
  background: var(--ink);
  color: var(--neon);
  border-color: var(--ink);
}

.nav-toggle-line,
.nav-toggle-line::before,
.nav-toggle-line::after {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
}

.nav-toggle-line {
  position: relative;
}

.nav-toggle-line::before,
.nav-toggle-line::after {
  content: "";
  position: absolute;
  left: 0;
  transition: top 0.2s ease, transform 0.2s ease;
}

.nav-toggle-line::before {
  top: -6px;
}

.nav-toggle-line::after {
  top: 6px;
}

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

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

.site-nav {
  display: flex;
  justify-content: flex-end;
  flex: 1;
}

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

.site-nav-item {
  position: relative;
}

.site-nav-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 12px;
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.site-nav-link::before {
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 500;
  color: var(--muted);
}

.site-nav-item:nth-child(1) .site-nav-link::before { content: "01"; }
.site-nav-item:nth-child(2) .site-nav-link::before { content: "02"; }
.site-nav-item:nth-child(3) .site-nav-link::before { content: "03"; }
.site-nav-item:nth-child(4) .site-nav-link::before { content: "04"; }
.site-nav-item:nth-child(5) .site-nav-link::before { content: "05"; }
.site-nav-item:nth-child(6) .site-nav-link::before { content: "06"; }

.site-nav-link:hover {
  color: var(--ink);
  background: var(--light-blue);
}

.site-nav-link[aria-current="page"] {
  border-bottom-color: var(--orange);
  color: var(--ink);
}

.site-nav-link[aria-current="page"]::before {
  color: var(--orange);
  font-weight: 800;
}

.site-footer {
  position: relative;
  background: var(--deep-blue);
  color: var(--silver);
  border-top: 1px solid rgba(201, 210, 222, 0.16);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  height: 4px;
  width: 100%;
  background: linear-gradient(90deg, var(--neon) 0 16%, var(--orange) 16% 30%, transparent 30%);
  pointer-events: none;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: 40px;
  padding-top: clamp(40px, 6vw, 72px);
  padding-bottom: 40px;
}

.footer-brand {
  font-size: 26px;
  font-weight: 900;
  letter-spacing: 0.1em;
  color: var(--neon);
  margin-bottom: 8px;
}

.footer-brand::after {
  content: "/";
  font-family: var(--font-mono);
  color: var(--orange);
  font-weight: 400;
}

.footer-statement {
  font-size: 14px;
  line-height: 1.7;
  color: var(--silver);
  max-width: 36em;
  margin-bottom: 0;
}

.footer-col-title {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--muted);
  border-bottom: 1px solid rgba(201, 210, 222, 0.14);
  padding-bottom: 10px;
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.footer-links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--silver);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s ease;
}

.footer-links a::before {
  content: "→";
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--orange);
  opacity: 0.85;
  transition: transform 0.2s ease;
}

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

.footer-links a:hover::before {
  transform: translateX(3px);
}

.footer-contact {
  font-style: normal;
  font-size: 14px;
  line-height: 1.8;
  display: grid;
  gap: 6px;
}

.footer-contact span {
  display: block;
}

.footer-meta {
  border-top: 1px solid rgba(201, 210, 222, 0.12);
  background: rgba(0, 0, 0, 0.12);
}

.footer-meta-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 56px;
  padding-top: 12px;
  padding-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted);
}

.footer-meta-note {
  color: rgba(201, 210, 222, 0.7);
}

.section {
  position: relative;
  padding: clamp(48px, 8vw, 96px) 0;
}

.section-header {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  margin-bottom: 32px;
}

.section-index {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 800;
  background: var(--ink);
  color: var(--neon);
  padding: 6px 10px;
  transform: skewX(-8deg);
  letter-spacing: 0.08em;
}

.section-title {
  font-size: clamp(26px, 4vw, 40px);
  margin: 0 0 8px;
}

.section-desc {
  color: var(--muted);
  max-width: 46em;
  margin-bottom: 0;
}

.lead {
  font-size: clamp(18px, 2.4vw, 24px);
  line-height: 1.7;
  font-weight: 500;
  color: var(--ink);
  max-width: 36em;
}

.grid {
  display: grid;
  gap: 24px;
}

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

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

.card {
  background: var(--white);
  border: 1px solid var(--silver);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.card-hover:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  background: var(--light-blue);
  color: var(--ink-light);
  border-radius: 999px;
}

.tag-neon {
  background: var(--neon);
  color: var(--ink);
}

.tag-orange {
  background: var(--orange);
  color: var(--white);
}

.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  border: 1px solid var(--ink);
  border-radius: 4px;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.btn:hover {
  background: var(--ink);
  color: var(--neon);
}

.btn-primary {
  background: var(--neon);
  border-color: var(--neon);
  color: var(--ink);
}

.btn-primary:hover {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--neon);
}

.btn-ghost {
  border-color: var(--silver);
  color: var(--ink);
}

.btn-ghost:hover {
  border-color: var(--ink);
}

.breadcrumb {
  margin-bottom: 24px;
  font-family: var(--font-mono);
  font-size: 13px;
}

.breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb li + li::before {
  content: "/";
  color: var(--muted);
  font-size: 11px;
}

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

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

.breadcrumb .breadcrumb-current {
  color: var(--ink);
  font-weight: 700;
}

.table-of-contents {
  border: 1px solid var(--silver);
  border-radius: var(--radius);
  background: var(--white);
  box-shadow: var(--shadow-card);
  padding: 24px;
}

.toc-title {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.16em;
  color: var(--ink-light);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--silver);
}

.toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: toc;
}

.toc-list li {
  counter-increment: toc;
  border-bottom: 1px dashed var(--silver);
}

.toc-list li:last-child {
  border-bottom: none;
}

.toc-list a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 4px;
  text-decoration: none;
  color: var(--ink);
}

.toc-list a::before {
  content: counter(toc, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--orange);
}

.toc-list a:hover {
  background: var(--light-blue);
}

.note {
  position: relative;
  background: var(--light-blue);
  border-left: 3px solid var(--ink-light);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 20px 24px;
  margin: 24px 0;
  font-size: 14px;
  color: var(--ink);
}

.note::before {
  content: "旁注";
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--ink-light);
  margin-bottom: 6px;
}

.note-accent {
  background: rgba(200, 240, 74, 0.22);
  border-left-color: var(--neon);
}

.note-accent::before {
  content: "导读";
  color: #3A4A14;
}

.stat {
  font-family: var(--font-mono);
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin-bottom: 12px;
}

.stat::after {
  content: "";
  display: block;
  width: 28px;
  height: 3px;
  background: var(--orange);
  margin-top: 8px;
}

.hr-rule {
  border: none;
  border-top: 1px solid var(--silver);
  margin: clamp(32px, 6vw, 64px) 0;
}

.image-frame {
  position: relative;
  overflow: hidden;
  background: var(--light-blue);
  border: 1px solid var(--silver);
  border-radius: var(--radius);
  display: block;
  width: 100%;
}

.image-frame::after {
  content: "";
  display: block;
  padding-bottom: 62.5%;
}

.image-frame-16x9::after {
  padding-bottom: 56.25%;
}

.image-frame-4x3::after {
  padding-bottom: 75%;
}

.image-frame-1x1::after {
  padding-bottom: 100%;
}

.image-frame-dark {
  background: var(--ink);
}

.image-frame-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--muted);
  background:
    linear-gradient(135deg, rgba(16, 36, 62, 0.06) 25%, transparent 25%) 0 0 / 16px 16px,
    linear-gradient(315deg, rgba(16, 36, 62, 0.06) 25%, transparent 25%) 0 0 / 16px 16px;
}

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

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 24px 0;
}

.filter-btn {
  padding: 8px 16px;
  font-family: var(--font-mono);
  font-size: 13px;
  border: 1px solid var(--silver);
  border-radius: 999px;
  background: var(--white);
  color: var(--ink);
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

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

.filter-btn.is-active {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--neon);
}

.filter-item {
  transition: opacity 0.25s ease;
}

.filter-item[data-filter-hidden="true"] {
  display: none !important;
}

@media (min-width: 1024px) {
  .brand-descriptor {
    display: inline-flex;
  }
}

@media (max-width: 900px) {
  .nav-toggle {
    display: inline-flex;
  }

  .header-main-inner {
    min-height: 64px;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: calc(100% + 1px);
    left: 0;
    right: 0;
    background: var(--white);
    border-bottom: 2px solid var(--ink);
    box-shadow: 0 16px 32px rgba(11, 27, 46, 0.14);
    padding: 12px 16px 16px;
    z-index: 90;
  }

  .site-nav[data-open] {
    display: block;
  }

  .site-nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav-item {
    border-bottom: 1px solid var(--silver);
  }

  .site-nav-item:last-child {
    border-bottom: none;
  }

  .site-nav-link {
    display: flex;
    padding: 14px 12px;
    font-size: 16px;
    border-bottom: none;
  }

  .site-nav-link[aria-current="page"] {
    background: var(--light-blue);
    border-left: 3px solid var(--orange);
  }
}

@media (max-width: 960px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

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

@media (max-width: 640px) {
  .header-cn-tag {
    display: none;
  }

  .header-cn-index {
    display: none;
  }

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

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

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
    scroll-behavior: auto !important;
  }
}