:root {
  --bg: #0A1F3C;
  --panel: #0D2A4A;
  --neon: #39FF14;
  --signal: #FF6B00;
  --ink: #EAF6FF;
  --muted: #9BB4D3;
  --line: #1E3A5F;
  --gold: #C9A45C;
  --font-display: Impact, "Arial Black", "Noto Sans SC", sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-data: "JetBrains Mono", "Roboto Mono", monospace;
  --shadow: 0 18px 40px rgba(2, 8, 20, .35), 0 0 0 1px rgba(30, 58, 95, .25);
  --ease: 160ms cubic-bezier(.2, .8, .2, 1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

html,
body {
  min-height: 100%;
}

body {
  margin: 0;
  overflow-x: hidden;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: -.02em;
  line-height: .95;
  margin: 0;
}

p {
  margin: 0;
}

ul,
ol {
  margin: 0;
  padding: 0;
}

li {
  list-style: none;
}

a {
  color: inherit;
  text-decoration: none;
}

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

button {
  border: 0;
  background: transparent;
  color: inherit;
  padding: 0;
  cursor: pointer;
}

[hidden] {
  display: none !important;
}

::selection {
  background: var(--neon);
  color: #0A1F3C;
}

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

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

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 400;
  transform: translateY(-250%);
  background: var(--signal);
  color: #0A1F3C;
  padding: 8px 14px;
  font-weight: 700;
  transition: transform var(--ease);
}

.skip-link:focus {
  transform: none;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 120;
  background: rgba(10, 31, 60, .96);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}

.site-header__progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  z-index: 2;
  pointer-events: none;
  background: linear-gradient(90deg, var(--neon), var(--signal));
}

.site-header__bar {
  max-width: 1440px;
  margin: 0 auto;
  min-height: 72px;
  padding: 12px clamp(20px, 4vw, 48px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

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

.brand__mark {
  position: relative;
  flex: 0 0 44px;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--neon) 0%, #0A1F3C 190%);
  color: #0A1F3C;
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 900;
  font-size: 22px;
  line-height: 1;
}

.brand__mark::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0 0 10px 10px;
  border-color: transparent transparent var(--signal) transparent;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  min-width: 0;
}

.brand__text strong {
  font-family: var(--font-display);
  font-style: italic;
  font-size: 20px;
  letter-spacing: .01em;
  text-transform: uppercase;
}

.brand__text small {
  color: var(--muted);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.site-header__flag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--muted);
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .08em;
  text-transform: uppercase;
  white-space: nowrap;
  padding-left: 18px;
  border-left: 1px solid var(--line);
}

.site-header__flag strong {
  color: var(--signal);
  font-weight: 800;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 10px;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.site-nav__link {
  position: relative;
  display: inline-block;
  padding: 10px 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 600;
  font-size: 14px;
  letter-spacing: .02em;
  transition: color var(--ease);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 100%;
  bottom: 5px;
  height: 2px;
  background: var(--neon);
  transition: right var(--ease);
}

.site-nav__link:hover,
.site-nav__link:focus-visible {
  color: var(--neon);
}

.site-nav__link:hover::after,
.site-nav__link:focus-visible::after {
  right: 10px;
}

.site-nav__link[aria-current="page"] {
  color: var(--neon);
}

.site-nav__link[aria-current="page"]::after {
  right: 10px;
  background: var(--signal);
}

.site-nav__cta {
  white-space: nowrap;
  margin-left: 6px;
}

.nav-toggle {
  display: none;
  width: 46px;
  height: 46px;
  padding: 12px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
}

.nav-toggle__bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--ink);
  transition: transform .16s, opacity .16s;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(6px) 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(-6px) rotate(-45deg);
}

.site-header__meta {
  max-width: 1440px;
  margin: 0 auto;
  padding: 8px clamp(20px, 4vw, 48px);
  display: flex;
  align-items: center;
  gap: 14px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.site-header__meta-item {
  white-space: nowrap;
}

.site-header__meta-sep {
  width: 3px;
  height: 3px;
  flex: 0 0 3px;
  background: var(--signal);
  transform: rotate(45deg);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 14px;
  line-height: 1;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform var(--ease), box-shadow var(--ease), background var(--ease), color var(--ease), border-color var(--ease);
}

.btn--signal {
  background: var(--signal);
  color: #0A1F3C;
  border-color: var(--signal);
  box-shadow: 4px 4px 0 var(--neon);
}

.btn--signal:hover {
  transform: translate(-1px, -1px);
  box-shadow: 6px 6px 0 var(--neon);
}

.btn--ghost {
  background: rgba(10, 31, 60, .4);
  color: var(--ink);
  border-color: var(--line);
}

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

.site-footer {
  background: var(--panel);
  border-top: 1px solid var(--line);
}

.site-footer__top {
  max-width: 1440px;
  margin: 0 auto;
  padding: clamp(48px, 6vw, 72px) clamp(20px, 4vw, 48px) 40px;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, .8fr) minmax(0, .95fr);
  gap: clamp(32px, 5vw, 64px);
}

.site-footer__brand {
  min-width: 0;
}

.brand--footer .brand__mark {
  flex-basis: 52px;
  width: 52px;
  height: 52px;
  font-size: 26px;
}

.brand--footer .brand__text strong {
  font-size: 24px;
}

.site-footer__note {
  margin-top: 20px;
  color: var(--muted);
  max-width: 48ch;
  font-size: 14px;
  line-height: 1.8;
}

.site-footer__col {
  min-width: 0;
}

.site-footer__title {
  font-family: var(--font-data);
  font-style: normal;
  font-size: 13px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 16px;
}

.site-footer__links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  column-gap: 18px;
}

.site-footer__links li {
  line-height: 1;
}

.site-footer__links a {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 0;
  color: var(--ink);
  text-decoration: none;
  font-size: 15px;
}

.site-footer__links a::before {
  content: "/";
  color: var(--neon);
  font-family: var(--font-data);
  font-size: 13px;
}

.site-footer__links a:hover {
  color: var(--neon);
}

.site-footer__address {
  margin-top: 18px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.9;
  font-style: normal;
}

.site-footer__service {
  margin-top: 16px;
  max-width: 44ch;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.8;
}

.site-footer__bottom {
  border-top: 1px solid var(--line);
}

.site-footer__bottom-inner {
  max-width: 1440px;
  margin: 0 auto;
  padding: 16px clamp(20px, 4vw, 48px);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 24px;
  color: var(--muted);
  font-size: 13px;
}

.site-footer__copy,
.site-footer__contact {
  margin: 0;
}

.site-footer__contact {
  font-family: var(--font-data);
}

.to-top {
  position: fixed;
  right: clamp(16px, 3vw, 40px);
  bottom: clamp(16px, 3vw, 40px);
  z-index: 320;
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border: 1px solid var(--neon);
  background: var(--signal);
  color: #0A1F3C;
  font-size: 24px;
  line-height: 1;
  box-shadow: 4px 4px 0 rgba(57, 255, 20, .35);
  transition: transform var(--ease), box-shadow var(--ease);
}

.to-top:hover {
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 rgba(57, 255, 20, .45);
}

.to-top[hidden] {
  display: none !important;
}

.container {
  max-width: 1440px;
  margin: 0 auto;
  padding-inline: clamp(20px, 4vw, 48px);
}

.section {
  padding-block: clamp(64px, 8vw, 120px);
}

.section--tight {
  padding-block: clamp(32px, 5vw, 64px);
}

.section--neon {
  background: linear-gradient(135deg, rgba(57, 255, 20, .10), transparent 55%);
}

.section--signal {
  background: linear-gradient(135deg, rgba(255, 107, 0, .12), transparent 60%);
}

.split-shell {
  display: grid;
  grid-template-columns: minmax(220px, 300px) minmax(0, 1fr);
  gap: clamp(28px, 5vw, 72px);
  align-items: start;
}

.index-panel {
  position: sticky;
  top: 132px;
  border-left: 3px solid var(--neon);
  padding-left: 18px;
}

.index-panel__title {
  font-family: var(--font-data);
  color: var(--signal);
  font-size: 13px;
  letter-spacing: .16em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.index-panel__list {
  border-top: 1px solid var(--line);
}

.index-panel__item {
  border-bottom: 1px solid var(--line);
}

.index-panel__item a {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: 12px 4px;
  color: var(--ink);
  text-decoration: none;
  font-size: 15px;
}

.index-panel__item .index-panel__num {
  font-family: var(--font-data);
  color: var(--muted);
  font-size: 12px;
}

.index-panel__item a:hover,
.index-panel__item.is-active a {
  color: var(--neon);
}

.content-panel {
  min-width: 0;
}

.chapter {
  display: grid;
  grid-template-columns: minmax(64px, .12fr) minmax(0, 1fr);
  gap: clamp(20px, 4vw, 48px);
  border-top: 1px solid var(--line);
  padding-top: 32px;
  margin-top: 32px;
  position: relative;
  animation: site-rise 120ms ease backwards;
}

@keyframes site-rise {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.chapter__number {
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(64px, 8vw, 120px);
  line-height: .8;
  color: rgba(155, 180, 211, .12);
  -webkit-text-stroke: 1px var(--line);
}

.chapter__kicker {
  font-family: var(--font-data);
  color: var(--signal);
  font-size: 13px;
  letter-spacing: .18em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.chapter__title {
  font-family: var(--font-display);
  font-size: clamp(28px, 4vw, 56px);
  margin-bottom: 14px;
}

.chapter__abstract {
  color: var(--muted);
  max-width: 58ch;
  font-size: 16px;
}

.data-card {
  position: relative;
  background: linear-gradient(145deg, rgba(13, 42, 74, .9), rgba(10, 31, 60, .5));
  border: 1px solid var(--line);
  padding: clamp(18px, 2vw, 26px);
  box-shadow: var(--shadow);
  transition: transform var(--ease), border-color var(--ease);
}

.data-card::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;
  width: 0;
  background: var(--neon);
  transition: width .2s;
}

.data-card:hover,
.data-card:focus-within {
  transform: translateY(-2px);
  border-color: var(--neon);
}

.data-card:hover::after,
.data-card:focus-within::after {
  width: 100%;
}

.data-card__meta {
  font-family: var(--font-data);
  color: var(--muted);
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  margin-bottom: 10px;
}

.data-card__title {
  font-family: var(--font-display);
  font-size: 24px;
  margin-bottom: 8px;
}

.data-card__value {
  font-family: var(--font-data);
  font-size: clamp(24px, 3vw, 40px);
  font-weight: 700;
  color: var(--neon);
}

.data-card__label {
  color: var(--muted);
  font-size: 14px;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  background: var(--signal);
  color: #0A1F3C;
  font-family: var(--font-data);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
  text-transform: uppercase;
}

.badge--neon {
  background: var(--neon);
  color: #0A1F3C;
}

.badge--ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--muted);
}

.badge--gold {
  background: var(--gold);
  color: #0A1F3C;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.card-grid > * {
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.grid {
  display: grid;
  gap: clamp(18px, 2vw, 28px);
}

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

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

.stat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.stat-grid__cell {
  background: var(--bg);
  padding: 16px 18px;
}

.stat-grid__value {
  display: block;
  font-family: var(--font-data);
  font-size: clamp(24px, 3vw, 40px);
  font-weight: 700;
  color: var(--neon);
}

.stat-grid__label {
  color: var(--muted);
  font-size: 13px;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-data);
  font-size: 14px;
  color: var(--ink);
}

.data-table th,
.data-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

.data-table th {
  color: var(--muted);
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  font-size: 12px;
}

.media-frame {
  position: relative;
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, rgba(13, 42, 74, .9), rgba(10, 31, 60, .4));
  border: 1px solid var(--line);
  overflow: hidden;
}

.media-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 0 58%, rgba(57, 255, 20, .22) 58%, transparent 60%);
}

.media-frame::after {
  content: "MEDIA";
  position: absolute;
  right: 12px;
  bottom: 8px;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--muted);
}

.media-frame--wide {
  aspect-ratio: 21 / 9;
}

.media-frame--tall {
  aspect-ratio: 4 / 5;
}

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

.study-board {
  border: 1px solid var(--line);
  background: linear-gradient(145deg, rgba(13, 42, 74, .9), rgba(10, 31, 60, .55));
  box-shadow: var(--shadow);
}

.study-board__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--line);
}

.study-board__tag {
  font-family: var(--font-data);
  color: var(--neon);
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
}

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

.study-board__summary {
  padding: 20px;
  border-right: 1px solid var(--line);
}

.study-board__aside {
  padding: 20px;
  background: rgba(10, 31, 60, .35);
}

.study-board__aside h3 {
  font-family: var(--font-data);
  font-style: normal;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: .14em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.study-board__aside ul {
  margin: 0;
  padding: 0;
}

.study-board__aside li {
  padding: 10px 0;
  border-top: 1px solid var(--line);
  font-size: 14px;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin: 0 0 24px;
  padding: 0;
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--muted);
}

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

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

.breadcrumb__sep {
  color: var(--signal);
}

.section-label {
  font-family: var(--font-data);
  color: var(--signal);
  font-size: 13px;
  letter-spacing: .16em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.section-title {
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(32px, 5vw, 64px);
  line-height: .95;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.prose {
  max-width: 76ch;
  color: var(--ink);
}

.prose p {
  margin-bottom: 1em;
}

.prose h2,
.prose h3,
.prose h4 {
  margin: 1.5em 0 .5em;
}

.prose a {
  color: var(--neon);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.prose ul {
  padding-left: 1.25em;
  margin-bottom: 1em;
}

.prose li {
  list-style-type: disc;
  margin: .4em 0;
}

.prose ol {
  padding-left: 1.25em;
  margin-bottom: 1em;
}

.prose ol li {
  list-style-type: decimal;
}

.prose blockquote {
  border-left: 3px solid var(--signal);
  padding: 4px 0 4px 16px;
  color: var(--muted);
  margin: 1em 0;
}

.data-positive {
  color: var(--neon);
}

.data-negative {
  color: var(--signal);
}

@media (max-width: 1280px) {
  .site-header__flag {
    display: none;
  }
}

@media (max-width: 1024px) {
  .site-header__bar {
    min-height: 64px;
  }

  .site-header__actions {
    gap: 10px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    top: auto;
    z-index: 260;
    max-height: 84vh;
    overflow-y: auto;
    background: var(--panel);
    border-top: 2px solid var(--neon);
    box-shadow: 0 -20px 60px rgba(2, 8, 20, .5);
    padding: 18px clamp(20px, 4vw, 32px) calc(18px + env(safe-area-inset-bottom));
    transform: translateY(105%);
    visibility: hidden;
    transition: transform .2s ease, visibility .2s ease;
    display: block;
  }

  .site-nav[data-open] {
    transform: translateY(0);
    visibility: visible;
  }

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

  .site-nav__link {
    width: 100%;
    padding: 14px 8px;
    border-bottom: 1px solid var(--line);
    font-size: 16px;
  }

  .site-nav__link::after {
    content: none;
  }

  .site-nav__link[aria-current="page"] {
    border-left: 3px solid var(--signal);
    color: var(--neon);
    padding-left: 16px;
  }

  .site-nav__cta {
    width: 100%;
    margin: 18px 0 0;
  }

  .split-shell {
    grid-template-columns: 1fr;
  }

  .index-panel {
    position: static;
  }

  .study-board__body {
    grid-template-columns: 1fr;
  }

  .study-board__summary {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
}

@media (max-width: 768px) {
  .site-header__meta {
    display: none;
  }

  .site-footer__top {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .site-footer__links {
    grid-template-columns: 1fr;
  }

  .stat-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 560px) {
  .brand__text small {
    display: none;
  }

  .stat-grid {
    grid-template-columns: 1fr;
  }

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

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

  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }

  .site-nav {
    transition: none;
  }

  .data-card {
    transform: none;
  }
}