:root {
  --color-bg: #FDFDFD;
  --color-panel: #FFFFFF;
  --color-panel-soft: #F5F5F5;
  --color-border: #E4E4E4;
  --color-accent: #CE4B22;
  --color-accent-dark: #A93A18;
  --color-text: #1B1B1B;
  --color-muted: #6C6C6C;
  --color-success: #1F8A4C;
  --color-warning: #B7791F;
  --color-error: #B02323;
  --color-flag-ink: #8F8F8F;
  --color-flag-tint: #ECECEC;
  --color-overlay: rgba(27, 27, 27, .36);
  --color-shadow-soft: rgba(27, 27, 27, .05);
  --color-shadow-mid: rgba(27, 27, 27, .08);
  --color-shadow-float: rgba(27, 27, 27, .14);
  --font-display: 'Inter', 'Noto Sans SC', -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  --radius-xs: 4px;
  --radius-s: 6px;
  --radius-m: 10px;
  --radius-l: 14px;
  --radius-pill: 999px;
  --shadow-button: 0 1px 2px var(--color-shadow-mid);
  --shadow-card: 0 1px 2px var(--color-shadow-soft), 0 10px 28px var(--color-shadow-soft);
  --shadow-float: 0 2px 4px var(--color-shadow-mid), 0 10px 24px var(--color-shadow-float);
  --content-max: 1360px;
  --reading-max: 820px;
  --header-height: 64px;
  --gutter: clamp(16px, 3vw, 40px);
  --section-space: clamp(64px, 9vw, 112px);
  --toc-offset: 82px;
  --motion-fast: 160ms;
  --motion-base: 360ms;
  --motion-slow: 640ms;
  --ease-standard: cubic-bezier(.22, 1, .36, 1);
}

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

html {
  scroll-behavior: smooth;
  background: var(--color-bg);
}

html.nav-open {
  overflow: hidden;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: clip;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

img {
  height: auto;
}

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

button,
summary {
  cursor: pointer;
}

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

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

h1,
h2,
h3,
h4 {
  color: var(--color-text);
  font-family: var(--font-display);
  text-wrap: balance;
}

h1 {
  margin-bottom: 24px;
  font-size: clamp(52px, 5vw, 72px);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.1;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(32px, 3.5vw, 48px);
  font-weight: 750;
  letter-spacing: -.015em;
  line-height: 1.16;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(21px, 2vw, 28px);
  line-height: 1.3;
}

p {
  margin-bottom: 1.15em;
}

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

li + li {
  margin-top: .45em;
}

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

code {
  overflow-wrap: anywhere;
  color: var(--color-text);
  font-size: .92em;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  padding: 20px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel-soft);
  overscroll-behavior-inline: contain;
  -webkit-overflow-scrolling: touch;
}

pre code {
  overflow-wrap: normal;
  white-space: pre;
}

hr {
  border: 0;
  border-top: 1px solid var(--color-border);
}

::selection {
  background: var(--color-accent);
  color: var(--color-panel);
}

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

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

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

.section-compact {
  padding-top: clamp(40px, 6vw, 72px);
  padding-bottom: clamp(40px, 6vw, 72px);
}

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

.mono,
.kicker,
.section-number {
  font-family: var(--font-mono);
}

.kicker {
  margin-bottom: 12px;
  color: var(--color-muted);
  font-size: 12px;
  letter-spacing: .2em;
  text-transform: uppercase;
}

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

.accent-text {
  color: var(--color-accent);
}

.panel,
.card {
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-m);
  background: var(--color-panel);
}

.card {
  padding: clamp(20px, 3vw, 32px);
  box-shadow: var(--shadow-card);
}

.soft-panel {
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-m);
  background: var(--color-panel-soft);
}

.badge,
.chip,
.tag {
  display: inline-flex;
  max-width: 100%;
  align-items: center;
  gap: 7px;
  min-height: 30px;
  padding: 4px 13px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-muted);
  font-size: 12.5px;
  line-height: 1.35;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.badge-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
}

.badge-success {
  color: var(--color-success);
}

.badge-warning {
  color: var(--color-warning);
}

.btn {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 10px 27px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
  box-shadow: var(--shadow-button);
  color: var(--color-text);
  font-weight: 650;
  line-height: 1.2;
  text-align: center;
  transition: background var(--motion-fast), border-color var(--motion-fast), color var(--motion-fast), transform var(--motion-fast);
}

.btn:hover {
  border-color: var(--color-muted);
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn:focus-visible,
button:focus-visible,
a:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

.btn-primary {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-panel);
}

.btn-primary:hover {
  border-color: var(--color-accent-dark);
  background: var(--color-accent-dark);
}

.btn-secondary {
  border-color: var(--color-border);
  background: var(--color-panel);
}

.btn-small {
  min-height: 36px;
  padding: 7px 15px;
  font-size: 13px;
}

.btn[aria-disabled="true"],
.btn:disabled {
  cursor: not-allowed;
  opacity: .55;
  transform: none;
}

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

.header-inner {
  display: flex;
  min-height: var(--header-height);
  align-items: stretch;
}

.site-brand {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  margin-right: 28px;
}

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

.brand-copy {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  white-space: nowrap;
}

.brand-word {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
}

.brand-local {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 500;
}

.desktop-nav {
  display: flex;
  min-width: 0;
  align-items: stretch;
  gap: 2px;
}

.desktop-nav a {
  position: relative;
  display: flex;
  align-items: center;
  padding-inline: 10px;
  color: var(--color-muted);
  font-size: 13px;
  white-space: nowrap;
}

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

.desktop-nav a.active {
  font-weight: 650;
}

.desktop-nav a.active::after {
  position: absolute;
  right: 10px;
  bottom: -1px;
  left: 10px;
  height: 2px;
  background: var(--color-text);
  content: "";
}

.header-tools {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}

.language-box {
  position: relative;
}

.language-trigger {
  display: inline-flex;
  min-height: 36px;
  align-items: center;
  gap: 6px;
  padding: 5px 8px;
  border: 0;
  background: transparent;
  color: var(--color-muted);
  font-size: 13px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 130;
  display: none;
  width: 150px;
  padding: 6px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
}

.language-box.open .language-menu {
  display: grid;
}

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

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

.login-button {
  display: inline-flex;
  min-height: 34px;
  align-items: center;
  justify-content: center;
  padding: 6px 15px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
  box-shadow: var(--shadow-button);
  font-size: 13px;
  font-weight: 650;
  white-space: nowrap;
}

.menu-toggle {
  display: none;
  width: 44px;
  min-width: 44px;
  height: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  padding: 0;
  border: 0;
  background: transparent;
}

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  width: 20px;
  height: 1px;
  background: var(--color-text);
}

.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: absolute;
  top: 100%;
  right: 0;
  left: 0;
  z-index: 125;
  display: none;
  max-height: calc(100dvh - var(--header-height));
  overflow-y: auto;
  padding: 8px var(--gutter) 18px;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-panel);
  overscroll-behavior: contain;
}

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

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 46px;
  align-items: center;
  padding: 10px 4px;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-muted);
}

.mobile-nav a.active {
  color: var(--color-text);
  font-weight: 700;
}

.mobile-language-links {
  display: grid;
  margin-top: 10px;
}

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

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

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

.footer-main {
  display: grid;
  grid-template-columns: minmax(220px, 1.3fr) repeat(3, minmax(150px, 1fr));
  gap: clamp(28px, 5vw, 72px);
  padding-top: 58px;
  padding-bottom: 44px;
}

.footer-brand {
  max-width: 360px;
}

.footer-brand .site-brand {
  margin-bottom: 17px;
}

.footer-brand p {
  color: var(--color-muted);
  font-size: 14px;
}

.footer-column h2 {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.footer-links {
  display: grid;
  gap: 8px;
}

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

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding-top: 20px;
  padding-bottom: 24px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 12px;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.prose {
  min-width: 0;
  color: var(--color-muted);
}

.prose h2,
.prose h3,
.prose strong {
  color: var(--color-text);
}

.prose h2 {
  margin-top: 2em;
}

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

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

.prose img,
.prose iframe {
  max-width: 100%;
}

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

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

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

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

.tilt,
.tilt-card {
  transform: rotate(-.35deg);
}

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

@media (max-width: 1180px) {
  .desktop-nav a {
    padding-inline: 7px;
    font-size: 12.5px;
  }

  .desktop-nav a.active::after {
    right: 7px;
    left: 7px;
  }

  .brand-local {
    display: none;
  }
}

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

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

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

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

@media (max-width: 768px) {
  h1 {
    font-size: clamp(32px, 9vw, 40px);
    line-height: 1.12;
  }

  h2 {
    font-size: clamp(27px, 7vw, 36px);
  }

  .site-brand {
    margin-right: 10px;
  }

  .brand-local {
    display: none;
  }

  .login-button {
    padding-inline: 12px;
  }

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

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

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

  .grid > *,
  [class*="grid"] > *,
  .card,
  .panel,
  .soft-panel {
    min-width: 0;
  }

  .tilt,
  .tilt-card {
    transform: none;
  }

  .btn {
    max-width: 100%;
  }

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

@media (max-width: 390px) {
  .brand-copy {
    gap: 0;
  }

  .header-tools {
    gap: 4px;
  }

  .login-button {
    min-height: 32px;
    padding-inline: 10px;
    font-size: 12px;
  }
}

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

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

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