:root {
  --color-canvas: #FBFAF7;
  --color-surface: #FFFFFF;
  --color-surface-soft: #F1EFE8;
  --color-line: #E4E1D7;
  --color-accent: #F0A11E;
  --color-accent-strong: #C57F08;
  --color-ink: #1A1A1C;
  --color-muted: #5E5C54;
  --color-success: #2E9E5B;
  --color-warning: #B45309;
  --color-error: #D64545;
  --color-dark: #1B1B1E;
  --color-dark-panel: #242428;
  --color-dark-text: #F4F2EC;
  --color-dark-muted: #9B988E;
  --color-grain: rgba(255, 255, 255, .04);
  --color-accent-soft: rgba(240, 161, 30, .16);
  --color-accent-glow: rgba(240, 161, 30, .35);
  --color-shadow-soft: rgba(26, 26, 28, .06);
  --color-shadow-main: rgba(26, 26, 28, .1);
  --color-overlay: rgba(26, 26, 28, .52);
  --color-ribbon: #CBC5B2;
  --color-flag-red: #C63B3F;
  --color-flag-blue: #31519B;
  --color-flag-green: #2E7D4F;
  --color-flag-white: #FFFFFF;

  --font-display: 'Inter', 'Noto Sans SC', -apple-system, 'PingFang SC', 'Hiragino Sans', 'Malgun Gothic', 'Microsoft YaHei', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', -apple-system, 'PingFang SC', 'Hiragino Sans', 'Malgun Gothic', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;

  --radius-xs: 5px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-pill: 999px;

  --shadow-card: 0 1px 2px var(--color-shadow-soft), 0 6px 18px var(--color-shadow-soft);
  --shadow-main: 0 1px 2px var(--color-shadow-main), 0 10px 26px var(--color-accent-glow);
  --shadow-lift: 0 18px 50px var(--color-shadow-soft);

  --page-max: 1240px;
  --content-max: 840px;
  --gutter: clamp(16px, 3vw, 32px);
  --header-height: 64px;
  --section-space: clamp(64px, 9vw, 112px);
  --focus-ring: 2px solid var(--color-accent-strong);
  --transition-fast: 150ms ease;
  --transition-reveal: 560ms cubic-bezier(.22, 1, .36, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 16px);
  background: var(--color-canvas);
}

html.nav-open {
  overflow: hidden;
}

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

main,
section,
article,
aside,
header,
footer,
nav,
div {
  min-width: 0;
}

img,
svg,
video {
  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;
}

a,
button,
summary,
[role="tab"],
input,
select,
textarea {
  -webkit-tap-highlight-color: var(--color-accent-soft);
}

a:focus-visible,
button:focus-visible,
summary:focus-visible,
[role="tab"]:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 3px;
}

p,
ul,
ol,
blockquote,
pre,
table {
  margin-top: 0;
  margin-bottom: 1.25em;
}

ul,
ol {
  padding-left: 1.4em;
}

h1,
h2,
h3,
h4 {
  margin-top: 0;
  color: var(--color-ink);
  font-family: var(--font-display);
  text-wrap: balance;
}

h1 {
  margin-bottom: 24px;
  font-size: clamp(52px, 5.5vw, 72px);
  font-weight: 900;
  letter-spacing: -.015em;
  line-height: 1.1;
}

h2 {
  margin-bottom: 20px;
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 850;
  letter-spacing: -.012em;
  line-height: 1.16;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(21px, 2.5vw, 28px);
  font-weight: 800;
  line-height: 1.3;
}

h4 {
  margin-bottom: 8px;
  font-size: 18px;
  font-weight: 750;
  line-height: 1.4;
}

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

code {
  max-width: 100%;
  padding: .12em .35em;
  overflow-wrap: anywhere;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-xs);
  background: var(--color-surface-soft);
  font-size: .9em;
}

pre {
  max-width: 100%;
  padding: 20px;
  overflow-x: auto;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-dark);
  color: var(--color-dark-text);
  line-height: 1.65;
  -webkit-overflow-scrolling: touch;
}

pre code {
  padding: 0;
  border: 0;
  background: transparent;
  color: inherit;
  overflow-wrap: normal;
}

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

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

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

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

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

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

.prose a:not(.button):not(.btn-main):not(.btn-sub) {
  color: var(--color-accent-strong);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: .2em;
}

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

.prose h3 {
  margin-top: 1.6em;
}

.prose img {
  border-radius: var(--radius-sm);
}

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

.section-compact {
  padding-top: clamp(42px, 6vw, 72px);
  padding-bottom: clamp(42px, 6vw, 72px);
}

.section-head {
  max-width: 760px;
  margin-bottom: clamp(28px, 5vw, 52px);
}

.section-head.center {
  margin-inline: auto;
  text-align: center;
}

.eyebrow {
  margin-bottom: 12px;
  color: var(--color-accent-strong);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.lead {
  color: var(--color-muted);
  font-size: clamp(17px, 2vw, 21px);
  line-height: 1.7;
}

.surface {
  background: var(--color-surface);
}

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

.dark-section {
  position: relative;
  overflow-x: clip;
  background: var(--color-dark);
  color: var(--color-dark-text);
}

.dark-section::before {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(var(--color-grain) 1px, transparent 1px),
    radial-gradient(var(--color-grain) 1px, transparent 1px);
  background-position: 0 0, 4px 6px;
  background-size: 9px 9px, 13px 13px;
  content: "";
  pointer-events: none;
}

.dark-section > * {
  position: relative;
  z-index: 1;
}

.dark-section h1,
.dark-section h2,
.dark-section h3,
.dark-section h4 {
  color: var(--color-dark-text);
}

.dark-section .muted,
.dark-section .lead {
  color: var(--color-dark-muted);
}

.card,
.panel {
  min-width: 0;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  box-shadow: var(--shadow-card);
}

.card {
  padding: clamp(20px, 3vw, 30px);
}

.panel {
  padding: clamp(24px, 4vw, 42px);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.button,
.btn-main,
.btn-sub,
.btn-login {
  display: inline-flex;
  min-width: 24px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 12px 24px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-weight: 750;
  line-height: 1.2;
  text-align: center;
  transition:
    color var(--transition-fast),
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    transform var(--transition-fast),
    box-shadow var(--transition-fast);
}

.button-primary,
.btn-main {
  background: var(--color-accent);
  color: var(--color-ink);
  box-shadow: var(--shadow-main);
}

.button-primary:hover,
.btn-main:hover {
  background: var(--color-accent-strong);
  transform: translateY(-1px);
}

.button-secondary,
.btn-sub,
.btn-login {
  border-color: var(--color-line);
  background: var(--color-surface);
  color: var(--color-ink);
  box-shadow: var(--shadow-card);
}

.button-secondary:hover,
.btn-sub:hover,
.btn-login:hover {
  border-color: var(--color-accent-strong);
}

.button-dark {
  background: var(--color-dark);
  color: var(--color-dark-text);
}

.button-dark:hover {
  background: var(--color-dark-panel);
  transform: translateY(-1px);
}

.button-small {
  min-height: 36px;
  padding: 8px 16px;
  font-size: 13px;
}

.button[aria-disabled="true"],
.button:disabled {
  cursor: not-allowed;
  opacity: .5;
  transform: none;
}

.button svg,
.btn-main svg,
.btn-sub svg {
  width: 18px;
  height: 18px;
  flex: 0 0 auto;
}

.badge,
.chip,
.tag {
  display: inline-flex;
  max-width: 100%;
  min-height: 28px;
  align-items: center;
  gap: 8px;
  padding: 5px 12px;
  overflow: hidden;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  color: var(--color-muted);
  font-size: 12.5px;
  line-height: 1.35;
  text-overflow: ellipsis;
}

.badge-dot,
.status-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-soft);
}

.status-dot.success {
  background: var(--color-success);
  box-shadow: none;
}

.tag {
  min-height: 24px;
  padding: 3px 9px;
  border-radius: var(--radius-xs);
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: 11px;
}

.h1-highlight,
.text-gradient {
  background: linear-gradient(128deg, var(--color-accent), var(--color-accent-strong));
  background-clip: text;
  color: transparent;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

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

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

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

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

.site-header-inner {
  position: relative;
  display: flex;
  min-height: var(--header-height);
  align-items: center;
}

.site-brand {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.site-brand img {
  width: 28px;
  height: 28px;
  flex: 0 0 auto;
}

.site-brand-name {
  color: var(--color-ink);
  font-size: 17px;
  font-weight: 850;
  letter-spacing: .01em;
}

.site-brand-local {
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 550;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 25px;
  margin-left: 44px;
}

.desktop-nav a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  color: var(--color-muted);
  font-size: 13.5px;
  font-weight: 550;
  white-space: nowrap;
}

.desktop-nav a:hover,
.desktop-nav a[aria-current="page"] {
  color: var(--color-ink);
}

.desktop-nav a[aria-current="page"] {
  font-weight: 750;
}

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

.language-picker {
  position: relative;
}

.language-toggle {
  display: inline-flex;
  min-width: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 7px 10px;
  border: 0;
  background: transparent;
  color: var(--color-muted);
  font-size: 13px;
}

.language-toggle::after {
  content: "▾";
  font-size: 10px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 120;
  display: none;
  width: 150px;
  padding: 7px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  box-shadow: var(--shadow-lift);
}

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

.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-surface-soft);
  color: var(--color-ink);
}

.header-login {
  min-height: 36px;
  padding: 7px 17px;
  font-size: 13px;
}

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

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  width: 18px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: var(--color-ink);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.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;
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines {
  background: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::before {
  transform: translateY(6px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::after {
  transform: translateY(-6px) rotate(-45deg);
}

.mobile-nav {
  position: absolute;
  top: 100%;
  right: var(--gutter);
  left: var(--gutter);
  z-index: 115;
  display: none;
  max-height: calc(100dvh - var(--header-height) - 16px);
  padding: 10px;
  overflow-y: auto;
  overscroll-behavior: contain;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  box-shadow: var(--shadow-lift);
}

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

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 46px;
  align-items: center;
  padding: 10px 12px;
  border-radius: var(--radius-xs);
  color: var(--color-muted);
  font-size: 14px;
}

.mobile-nav a:hover,
.mobile-nav a[aria-current="page"],
.mobile-nav a[aria-current="true"] {
  background: var(--color-surface-soft);
  color: var(--color-ink);
}

.mobile-nav-divider {
  height: 1px;
  margin: 8px 0;
  background: var(--color-line);
}

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

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

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

.footer-main {
  display: grid;
  grid-template-columns: minmax(240px, 1.25fr) repeat(3, minmax(150px, .75fr));
  gap: 38px;
  padding-top: 64px;
  padding-bottom: 48px;
}

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

.footer-brand .site-brand {
  margin-bottom: 16px;
}

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

.footer-title {
  margin-bottom: 14px;
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 750;
  letter-spacing: .09em;
}

.footer-links {
  display: grid;
  gap: 7px;
}

.footer-links a {
  display: inline-flex;
  min-height: 30px;
  align-items: center;
  color: var(--color-muted);
  font-size: 13.5px;
}

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

.footer-bottom {
  display: flex;
  min-height: 66px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--color-line);
  color: var(--color-muted);
  font-size: 12.5px;
}

.footer-legal,
.footer-languages {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.footer-bottom a {
  min-height: 24px;
}

.tilt-card {
  transform: rotate(-.45deg);
  transform-origin: center;
}

body:has(.toc-tabs) section[id] {
  scroll-margin-top: 132px;
}

@media (max-width: 1080px) {
  .desktop-nav {
    gap: 17px;
    margin-left: 25px;
  }

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

  .site-brand-local {
    display: none;
  }

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

@media (max-width: 860px) {
  h1 {
    font-size: clamp(34px, 7vw, 40px);
  }

  .desktop-nav,
  .language-picker {
    display: none;
  }

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

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

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

@media (max-width: 640px) {
  :root {
    --gutter: 16px;
    --section-space: 64px;
  }

  body {
    font-size: 15px;
  }

  h1 {
    font-size: clamp(28px, 10vw, 40px);
    letter-spacing: -.01em;
  }

  h2 {
    font-size: clamp(27px, 8vw, 36px);
  }

  .wrap,
  .shell {
    width: 100%;
    padding-inline: var(--gutter);
  }

  .site-brand-local {
    display: none;
  }

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

  .mobile-nav {
    right: 12px;
    left: 12px;
  }

  .footer-main {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding-top: 50px;
  }

  .footer-bottom {
    align-items: flex-start;
    flex-direction: column;
    padding-top: 20px;
    padding-bottom: 24px;
  }

  .tilt-card {
    transform: none;
  }

  .button,
  .btn-main,
  .btn-sub {
    max-width: 100%;
  }
}

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

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

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