:root {
  --color-canvas: #FFFFFF;
  --color-panel: #FAFAFB;
  --color-panel-strong: #F2F3F5;
  --color-line: #E2E4E8;
  --color-signal: #0847F5;
  --color-signal-deep: #0533B8;
  --color-ink: #101215;
  --color-ink-muted: #6C7076;
  --color-positive: #1B7F4D;
  --color-caution: #B37400;
  --color-negative: #C23A2E;
  --color-flag-red: #CE3B33;
  --color-flag-navy: #2E4593;
  --color-overlay: rgba(16, 18, 21, 0.42);
  --font-display: Georgia, "Times New Roman", "Noto Serif CJK SC", "Songti SC", SimSun, serif;
  --font-body: "Inter", "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", -apple-system, "PingFang SC", "Hiragino Sans", "Malgun Gothic", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --radius-small: 8px;
  --radius-medium: 12px;
  --radius-pill: 999px;
  --line-thin: 1px;
  --header-height: 72px;
  --content-wide: 1360px;
  --content-main: 1280px;
  --content-reading: 56rem;
  --gutter: clamp(16px, 3.2vw, 40px);
  --section-space: clamp(72px, 10vw, 144px);
  --toc-offset: 88px;
  --motion-fast: 150ms;
  --motion-base: 420ms;
  --shadow-none: 0 0 0 transparent;
}

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

html {
  min-width: 320px;
  scroll-behavior: smooth;
  background: var(--color-canvas);
}

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 320px;
  margin: 0;
  overflow-x: clip;
  color: var(--color-ink);
  background: var(--color-canvas);
  font-family: var(--font-body);
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body,
button,
input,
select,
textarea {
  font: inherit;
}

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

img {
  height: auto;
}

button,
input,
select,
textarea {
  color: inherit;
}

button,
summary {
  cursor: pointer;
}

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

p,
h1,
h2,
h3,
h4,
ul,
ol,
dl,
dd,
figure,
blockquote,
pre {
  margin: 0;
}

ul,
ol {
  padding: 0;
}

li {
  min-width: 0;
}

table {
  border-collapse: collapse;
  border-spacing: 0;
}

code,
kbd,
samp,
pre {
  font-family: var(--font-mono);
}

code {
  overflow-wrap: anywhere;
  word-break: break-word;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  -webkit-overflow-scrolling: touch;
}

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

::selection {
  color: var(--color-canvas);
  background: var(--color-signal);
}

.wrap {
  width: 100%;
  max-width: var(--content-main);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.wrap-wide {
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.reading-wrap {
  width: 100%;
  max-width: calc(var(--content-reading) + (var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section-space {
  padding-top: var(--section-space);
  padding-bottom: var(--section-space);
}

.flow > * + * {
  margin-top: 1.15em;
}

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

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

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

.grid > *,
.cluster > *,
.site-header__inner > *,
.hero-layout > *,
.site-footer__grid > * {
  min-width: 0;
}

.flex-icon,
.icon-box,
.status-dot,
.chip::before,
.eyebrow::before {
  flex-shrink: 0;
}

.display-title,
h1 {
  max-width: 100%;
  font-family: var(--font-display);
  font-size: clamp(52px, 5.2vw, 72px);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: 0;
  text-wrap: balance;
}

h2 {
  font-family: var(--font-display);
  font-size: clamp(34px, 3.6vw, 52px);
  font-weight: 400;
  line-height: 1.16;
  text-wrap: balance;
}

h3 {
  font-family: var(--font-display);
  font-size: clamp(24px, 2.2vw, 34px);
  font-weight: 400;
  line-height: 1.25;
  text-wrap: balance;
}

h4 {
  font-size: 18px;
  line-height: 1.35;
}

.no-break {
  white-space: nowrap;
}

.kicker,
.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--color-ink-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.eyebrow::before {
  width: 22px;
  height: 1px;
  content: "";
  background: var(--color-ink);
}

.lead {
  max-width: 52ch;
  color: var(--color-ink-muted);
  font-size: clamp(17px, 1.6vw, 21px);
  line-height: 1.75;
}

.muted {
  color: var(--color-ink-muted);
}

.mono {
  font-family: var(--font-mono);
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--color-ink);
  font-weight: 600;
}

.text-link:hover {
  color: var(--color-signal);
  border-color: var(--color-signal);
}

.btn,
.btn-main,
.btn-sub,
.btn-login {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  max-width: 100%;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.2;
  text-align: center;
  transition:
    color var(--motion-fast) ease,
    background-color var(--motion-fast) ease,
    border-color var(--motion-fast) ease,
    opacity var(--motion-fast) ease;
}

.btn-main {
  color: var(--color-canvas);
  background: var(--color-signal);
}

.btn-main:hover {
  background: var(--color-signal-deep);
}

.btn-sub {
  color: var(--color-ink);
  border-color: var(--color-line);
  background: var(--color-canvas);
}

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

.btn-dark,
.btn-login {
  color: var(--color-canvas);
  background: var(--color-ink);
}

.btn-dark:hover,
.btn-login:hover {
  opacity: 0.82;
}

.btn:disabled,
.btn-main:disabled,
.btn-sub:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.panel,
.card {
  min-width: 0;
  border: var(--line-thin) solid var(--color-line);
  border-radius: var(--radius-medium);
  background: var(--color-canvas);
  box-shadow: var(--shadow-none);
}

.panel-soft {
  background: var(--color-panel);
}

.rule {
  height: 1px;
  border: 0;
  background: var(--color-line);
}

.chips,
.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip,
.badge,
.tag {
  display: inline-flex;
  min-width: 0;
  max-width: 100%;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  padding: 6px 13px;
  overflow: hidden;
  color: var(--color-ink-muted);
  background: var(--color-canvas);
  font-size: 12px;
  line-height: 1.25;
  text-overflow: ellipsis;
}

.chip::before {
  width: 5px;
  height: 5px;
  content: "";
  border: 1px solid var(--color-ink-muted);
}

.badge--signal,
.tag--signal {
  color: var(--color-canvas);
  border-color: var(--color-signal);
  background: var(--color-signal);
}

.badge--positive {
  color: var(--color-positive);
  border-color: var(--color-positive);
}

.site-header {
  position: relative;
  z-index: 100;
  height: var(--header-height);
  border-bottom: 1px solid var(--color-line);
  background: var(--color-canvas);
}

.site-header__inner {
  position: relative;
  display: flex;
  width: 100%;
  max-width: var(--content-wide);
  height: 100%;
  margin-inline: auto;
  padding-inline: var(--gutter);
  align-items: center;
}

.site-brand {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
  gap: 10px;
}

.site-brand img {
  width: 30px;
  height: 30px;
}

.site-brand__english {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.site-brand__local {
  color: var(--color-ink-muted);
  font-size: 13px;
  font-weight: 500;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 26px;
  margin-left: 52px;
}

.desktop-nav a {
  color: var(--color-ink-muted);
  font-size: 13.5px;
  letter-spacing: 0.01em;
  white-space: nowrap;
  transition: color var(--motion-fast) ease;
}

.desktop-nav a:hover,
.desktop-nav a.is-active {
  color: var(--color-ink);
}

.desktop-nav a.is-active {
  font-weight: 600;
}

.header-tools {
  display: flex;
  margin-left: auto;
  align-items: center;
  gap: 14px;
}

.language-picker {
  position: relative;
}

.language-button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 6px;
  border: 0;
  padding: 0 8px;
  color: var(--color-ink-muted);
  background: transparent;
  font-size: 13px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  display: none;
  width: 156px;
  padding: 7px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  background: var(--color-canvas);
}

.language-picker.is-open .language-menu {
  display: grid;
}

.language-menu a {
  display: flex;
  min-height: 40px;
  align-items: center;
  border-radius: var(--radius-small);
  padding: 8px 10px;
  color: var(--color-ink-muted);
  font-size: 13px;
}

.language-menu a:hover,
.language-menu a[aria-current="true"] {
  color: var(--color-ink);
  background: var(--color-panel-strong);
}

.menu-toggle {
  display: none;
  min-width: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  padding: 0;
  background: var(--color-canvas);
}

.menu-toggle__lines,
.menu-toggle__lines::before,
.menu-toggle__lines::after {
  display: block;
  width: 18px;
  height: 1px;
  background: var(--color-ink);
}

.menu-toggle__lines {
  position: relative;
}

.menu-toggle__lines::before,
.menu-toggle__lines::after {
  position: absolute;
  left: 0;
  content: "";
}

.menu-toggle__lines::before {
  top: -6px;
}

.menu-toggle__lines::after {
  top: 6px;
}

.mobile-nav {
  position: fixed;
  z-index: 110;
  top: var(--header-height);
  right: 0;
  left: 0;
  display: none;
  max-height: calc(100dvh - var(--header-height));
  padding: 10px var(--gutter) 24px;
  overflow-y: auto;
  overscroll-behavior: contain;
  border-bottom: 1px solid var(--color-line);
  background: var(--color-canvas);
}

.mobile-nav.is-open {
  display: block;
}

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 48px;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--color-line);
  color: var(--color-ink);
  font-size: 15px;
}

.mobile-nav a.is-active {
  color: var(--color-signal);
  font-weight: 600;
}

.mobile-nav__languages {
  display: grid;
  margin-top: 12px;
}

.mobile-nav__languages a {
  color: var(--color-ink-muted);
}

.nav-veil {
  position: fixed;
  z-index: 90;
  inset: var(--header-height) 0 0;
  display: none;
  border: 0;
  background: var(--color-overlay);
}

.nav-veil.is-open {
  display: block;
}

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

.site-footer__grid {
  display: grid;
  grid-template-columns: minmax(220px, 1.25fr) repeat(3, minmax(150px, 1fr));
  gap: 54px;
  padding-top: 72px;
  padding-bottom: 54px;
}

.footer-brand {
  display: grid;
  align-content: start;
  gap: 18px;
}

.footer-brand .site-brand {
  width: max-content;
}

.footer-brand p {
  max-width: 34ch;
  color: var(--color-ink-muted);
  font-size: 14px;
}

.footer-column h2 {
  margin-bottom: 18px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

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

.footer-links a {
  color: var(--color-ink-muted);
  font-size: 13.5px;
}

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

.footer-bottom {
  display: flex;
  padding-top: 22px;
  padding-bottom: 26px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--color-line);
  color: var(--color-ink-muted);
  font-size: 12px;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

.reveal {
  transition:
    opacity var(--motion-base) ease,
    transform var(--motion-base) ease;
}

.reveal.pending {
  opacity: 0;
  transform: translateY(16px);
}

.reveal.shown {
  opacity: 1;
  transform: none;
}

.prose {
  color: var(--color-ink);
  font-size: 16px;
  line-height: 1.85;
}

.prose > * + * {
  margin-top: 1.2em;
}

.prose h2 {
  margin-top: 2.1em;
}

.prose h3 {
  margin-top: 1.7em;
}

.prose ul,
.prose ol {
  padding-left: 1.35em;
}

.prose a {
  color: var(--color-signal);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose pre {
  padding: 20px;
  border-radius: var(--radius-small);
  color: var(--color-canvas);
  background: var(--color-ink);
}

body:has(.toc-tabs) section[id] {
  scroll-margin-top: calc(var(--toc-offset) + 24px);
}

@media (max-width: 1180px) {
  .desktop-nav {
    gap: 17px;
    margin-left: 28px;
  }

  .desktop-nav a {
    font-size: 12.5px;
  }
}

@media (max-width: 980px) {
  .desktop-nav,
  .language-picker {
    display: none;
  }

  .header-tools {
    margin-left: auto;
  }

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

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

@media (max-width: 768px) {
  .display-title,
  h1 {
    font-size: clamp(28px, 9.5vw, 40px);
    line-height: 1.14;
    letter-spacing: 0;
  }

  h2 {
    font-size: clamp(28px, 8vw, 38px);
  }

  h3 {
    font-size: clamp(22px, 6.5vw, 30px);
  }

  .site-brand__local {
    display: none;
  }

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

@media (max-width: 640px) {
  :root {
    --gutter: 16px;
    --header-height: 64px;
    --toc-offset: 76px;
  }

  body {
    overflow-x: clip;
  }

  .site-header__inner,
  .wrap,
  .wrap-wide,
  .reading-wrap {
    padding-inline: var(--gutter);
  }

  .site-brand img {
    width: 28px;
    height: 28px;
  }

  .btn,
  .btn-main,
  .btn-sub,
  .btn-login {
    padding-inline: 20px;
  }

  .header-tools {
    margin-left: auto;
    gap: 8px;
  }

  .btn-login {
    min-height: 40px;
    padding: 9px 16px;
    font-size: 13px;
  }

  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .tilt,
  [class*="tilt-"] {
    transform: none;
  }

  .decorative-orbit,
  .decorative-disc,
  .decorative-watermark,
  .hero-atmosphere {
    max-width: 100%;
  }

  .prose > .data-table {
    display: block;
    max-width: 100%;
    min-width: 0;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
}

@media (max-width: 420px) {
  .site-brand__english {
    font-size: 15px;
  }

  .header-tools {
    gap: 6px;
  }

  .btn-login {
    padding-inline: 13px;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .reveal,
  .reveal.pending {
    opacity: 1;
    transform: none;
  }
}