:root {
  --c-ink: #0A0F1E;
  --c-paper: #F4E9D8;
  --c-neon: #C6FF4D;
  --c-orange: #FF6B35;
  --c-ice: #00E5FF;
  --c-stone: #8B93A7;
  --c-brown: #2B1208;
  --c-white: #FFFFFF;
  --c-yellow: #F0E442;
  --font-sans: system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-data: 'Roboto Mono', 'SFMono-Regular', Consolas, monospace;
  --header-h: 64px;
  --sidebar-w: 240px;
  --tabbar-h: 56px;
  --radius: 0px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--c-ink);
  color: var(--c-paper);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  margin: 0;
  font-weight: 900;
  font-style: italic;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

p {
  margin: 0 0 1em;
}

a {
  color: var(--c-ice);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

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

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

.skip-link {
  position: fixed;
  top: -120px;
  left: 16px;
  z-index: 1000;
  background: var(--c-neon);
  color: var(--c-ink);
  padding: 10px 16px;
  font-weight: 700;
  text-decoration: none;
}

.skip-link:focus {
  top: 16px;
}

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

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  background: var(--c-ink);
  border-bottom: 1px solid rgba(0, 229, 255, 0.18);
  z-index: 100;
}

.site-header__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  padding: 0 clamp(16px, 3vw, 48px);
}

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

.brand__mark {
  position: relative;
  overflow: hidden;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  background: linear-gradient(135deg, var(--c-neon) 0%, var(--c-neon) 40%, var(--c-orange) 55%, var(--c-orange) 100%);
  border-radius: 2px;
  transform: skewX(-12deg);
}

.brand__mark::before {
  content: "";
  position: absolute;
  top: 50%;
  left: -12px;
  width: 60px;
  height: 2px;
  background: rgba(10, 15, 30, 0.5);
  transform: rotate(-24deg);
  box-shadow: 0 8px 0 rgba(10, 15, 30, 0.25);
}

.brand__name {
  font-size: 20px;
  font-weight: 900;
  font-style: italic;
  letter-spacing: 0.02em;
  color: var(--c-white);
  white-space: nowrap;
}

.brand__sub {
  font-size: 12px;
  color: var(--c-stone);
  border-left: 1px solid #2A3144;
  padding-left: 10px;
  white-space: nowrap;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 18px;
}

.search-placeholder {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid #2A3144;
  border-radius: 999px;
  color: var(--c-stone);
  font-size: 13px;
  cursor: default;
}

.search-placeholder__icon {
  position: relative;
  display: inline-block;
  width: 14px;
  height: 14px;
}

.search-placeholder__icon::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 10px;
  height: 10px;
  border: 1.5px solid currentColor;
  border-radius: 50%;
}

.search-placeholder__icon::after {
  content: "";
  position: absolute;
  right: -1px;
  bottom: 1px;
  width: 5px;
  height: 1.5px;
  background: currentColor;
  transform: rotate(45deg);
  transform-origin: right center;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid rgba(198, 255, 77, 0.25);
  cursor: pointer;
  color: var(--c-paper);
  font-size: 11px;
  text-transform: uppercase;
}

.nav-toggle__line {
  display: block;
  width: 22px;
  height: 2px;
  background: currentColor;
  transition: transform 0.25s, opacity 0.25s;
}

.nav-toggle__label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(2) {
  transform: translateY(-7px) rotate(-45deg);
}

.header-progress {
  position: absolute;
  bottom: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--c-neon), var(--c-ice));
  transition: width 0.1s linear;
  z-index: 101;
}

.site-nav {
  position: fixed;
  top: var(--header-h);
  left: 0;
  bottom: 0;
  width: var(--sidebar-w);
  background: var(--c-ink);
  border-right: 1px solid rgba(0, 229, 255, 0.18);
  padding: 28px 0;
  z-index: 80;
  display: flex;
  flex-direction: column;
  transform: translateX(0);
  transition: transform 0.3s ease;
}

.site-nav__frame {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 6px;
  background: linear-gradient(180deg, var(--c-neon), var(--c-ice), var(--c-orange));
  opacity: 0.2;
  pointer-events: none;
}

.site-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.nav-link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 20px 10px 24px;
  color: var(--c-paper);
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
  border-left: 3px solid transparent;
  position: relative;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.nav-link::after {
  content: "";
  position: absolute;
  right: 16px;
  top: 50%;
  width: 6px;
  height: 6px;
  background: currentColor;
  opacity: 0;
  transform: translateY(-50%) rotate(45deg);
  transition: opacity 0.2s;
}

.nav-link:hover {
  color: var(--c-neon);
  border-left-color: var(--c-neon);
  background: rgba(198, 255, 77, 0.06);
}

.nav-link:hover::after {
  opacity: 0.6;
}

.nav-link[aria-current="page"] {
  color: var(--c-ink);
  background: var(--c-neon);
  border-left-color: var(--c-orange);
  font-style: italic;
}

.nav-link[aria-current="page"]::after {
  opacity: 1;
  color: var(--c-orange);
}

.nav-link__index {
  font-family: var(--font-data);
  font-size: 12px;
  color: inherit;
  opacity: 0.6;
}

.nav-link[aria-current="page"] .nav-link__index {
  opacity: 0.8;
  color: var(--c-ink);
}

.site-nav__foot {
  margin-top: auto;
  padding: 16px 24px 0;
  border-top: 1px solid #1E2536;
  display: flex;
  justify-content: space-between;
  font-family: var(--font-data);
  font-size: 11px;
  color: var(--c-stone);
  letter-spacing: 0.04em;
}

.site-nav__lang {
  color: var(--c-ice);
  font-weight: 700;
}

.mobile-tabbar {
  display: none;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

[data-revealed] {
  opacity: 1;
  transform: none;
}

.site-main {
  padding-top: var(--header-h);
  min-height: 80vh;
}

.container {
  width: min(1200px, 100% - 2 * clamp(16px, 4vw, 64px));
  margin-inline: auto;
}

.content-wrap {
  padding: clamp(24px, 4vw, 64px) clamp(16px, 3vw, 48px);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0 0 24px;
  padding: 8px 0;
  font-size: 14px;
  color: var(--c-stone);
}

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

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

.breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--c-stone);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 10px 24px;
  font-family: var(--font-sans);
  font-weight: 700;
  font-style: italic;
  font-size: 15px;
  border: 0;
  cursor: pointer;
  text-decoration: none;
  background: var(--c-neon);
  color: var(--c-ink);
  transform: skewX(-8deg);
  transition: filter 0.2s, transform 0.2s;
}

.btn:hover {
  filter: brightness(1.1);
  transform: skewX(-8deg) translateY(-1px);
}

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

.btn--accent {
  background: var(--c-orange);
  color: var(--c-white);
}

.btn--ghost {
  background: transparent;
  color: var(--c-ice);
  box-shadow: inset 0 0 0 2px currentColor;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
  border-bottom: 2px solid rgba(244, 233, 216, 0.2);
  padding-bottom: 12px;
}

.section-head__title {
  font-size: clamp(24px, 4vw, 40px);
}

.section-head__link {
  color: var(--c-ice);
  font-weight: 700;
  text-decoration: none;
}

.index-map {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 20px;
}

.topic-card {
  grid-column: span 4;
  background: var(--c-paper);
  color: var(--c-brown);
  padding: 24px;
  border-top: 4px solid var(--c-orange);
  position: relative;
  box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.25);
}

.topic-card__title {
  font-size: 20px;
  margin-bottom: 8px;
}

.data-number {
  font-family: var(--font-data);
  font-size: clamp(28px, 6vw, 48px);
  font-weight: 700;
  color: var(--c-neon);
  line-height: 1;
}

.badge {
  display: inline-block;
  padding: 4px 10px;
  background: var(--c-ice);
  color: var(--c-ink);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.badge--hot {
  background: var(--c-orange);
  color: var(--c-white);
}

.media-frame {
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.12), rgba(198, 255, 77, 0.08));
  border: 1px solid rgba(0, 229, 255, 0.2);
  position: relative;
  overflow: hidden;
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(45deg, rgba(255, 255, 255, 0.03) 0 10px, transparent 10px 20px);
}

.img-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10, 15, 30, 0.35);
  color: var(--c-stone);
  font-size: 13px;
  letter-spacing: 0.1em;
}

.site-footer {
  position: relative;
  background: var(--c-paper);
  color: var(--c-brown);
  padding: 56px clamp(24px, 5vw, 72px) 72px;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: repeating-linear-gradient(90deg, var(--c-orange) 0 20px, var(--c-neon) 20px 40px, var(--c-ice) 40px 60px);
}

.site-footer__inner {
  max-width: 1200px;
  margin: 0 auto;
}

.site-footer__top {
  display: grid;
  grid-template-columns: 1.5fr 0.8fr 1.2fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand__name {
  display: block;
  font-size: 26px;
  font-weight: 900;
  font-style: italic;
  color: var(--c-brown);
}

.footer-brand__tagline {
  margin-top: 8px;
  font-size: 14px;
  color: var(--c-brown);
  opacity: 0.7;
}

.footer-links__title {
  font-size: 14px;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 14px;
  color: var(--c-brown);
  border-bottom: 2px solid var(--c-orange);
  display: inline-block;
  padding-bottom: 4px;
}

.footer-links__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.footer-links a {
  color: var(--c-brown);
  text-decoration: none;
  font-weight: 600;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s, color 0.2s;
}

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

.footer-meta p {
  margin: 0 0 6px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--c-brown);
}

.site-footer__bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  border-top: 1px solid rgba(43, 18, 8, 0.18);
  padding-top: 20px;
}

.site-footer__claim {
  font-size: 13px;
  max-width: 720px;
  color: var(--c-brown);
  opacity: 0.75;
  margin: 0;
}

.site-footer__copy {
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--c-brown);
  margin: 0;
  white-space: nowrap;
}

@media (max-width: 959px) {
  .site-nav {
    transform: translateX(-100%);
    width: min(320px, 86vw);
    padding-bottom: calc(var(--tabbar-h) + 24px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  }

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

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

  .mobile-tabbar {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--tabbar-h);
    background: rgba(10, 15, 30, 0.95);
    border-top: 1px solid rgba(198, 255, 77, 0.2);
    z-index: 120;
  }

  .mobile-tabbar .tabbar-link {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    color: var(--c-stone);
    text-decoration: none;
    font-size: 11px;
    font-weight: 600;
  }

  .mobile-tabbar .tabbar-link[aria-current="page"] {
    color: var(--c-neon);
  }

  .tabbar-link__icon {
    width: 20px;
    height: 20px;
    display: inline-block;
    position: relative;
  }

  .tabbar-link__icon--home::before {
    content: "";
    position: absolute;
    top: 2px;
    left: 4px;
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-bottom: 7px solid currentColor;
  }

  .tabbar-link__icon--home::after {
    content: "";
    position: absolute;
    bottom: 2px;
    left: 6px;
    width: 8px;
    height: 5px;
    background: currentColor;
  }

  .tabbar-link__icon--data::before {
    content: "";
    position: absolute;
    left: 2px;
    bottom: 2px;
    width: 3px;
    height: 8px;
    background: currentColor;
  }

  .tabbar-link__icon--data::after {
    content: "";
    position: absolute;
    left: 8px;
    bottom: 2px;
    width: 3px;
    height: 14px;
    background: currentColor;
    box-shadow: 6px 0 0 currentColor;
  }

  .tabbar-link__icon--update::before {
    content: "";
    position: absolute;
    left: 2px;
    top: 3px;
    width: 13px;
    height: 13px;
    border: 2px solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
  }

  .tabbar-link__icon--update::after {
    content: "";
    position: absolute;
    left: 3px;
    top: 5px;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-bottom: 6px solid currentColor;
    transform: rotate(-35deg);
  }

  .tabbar-link__icon--faq::before {
    content: "?";
    position: absolute;
    left: 2px;
    top: 2px;
    width: 16px;
    height: 16px;
    font-size: 16px;
    font-weight: 900;
    line-height: 16px;
    text-align: center;
    background: currentColor;
    color: var(--c-ink);
    border-radius: 50%;
  }

  .tabbar-link__icon--faq::after {
    content: "";
    position: absolute;
    left: 14px;
    bottom: 2px;
    width: 0;
    height: 0;
    border-left: 4px solid transparent;
    border-right: 0;
    border-top: 6px solid currentColor;
    transform: rotate(20deg);
  }

  body {
    padding-bottom: var(--tabbar-h);
  }

  .site-footer {
    padding-bottom: calc(var(--tabbar-h) + 32px);
  }

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

  .topic-card {
    grid-column: span 6;
  }
}

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

  .search-placeholder__text {
    display: none;
  }

  .search-placeholder {
    padding: 8px;
  }

  .site-footer__top {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .topic-card {
    grid-column: span 12;
  }

  .site-footer__bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (min-width: 960px) {
  .site-main {
    margin-left: var(--sidebar-w);
  }

  .site-footer {
    margin-left: var(--sidebar-w);
  }
}

.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;
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}