:root {
  --color-canvas: #FFFFFF;
  --color-panel: #F6F6F5;
  --color-panel-strong: #EDEDEC;
  --color-line: #E3E3E1;
  --color-line-strong: #D3D3D0;
  --color-accent: #EB5E28;
  --color-accent-dark: #C44712;
  --color-ink: #15171B;
  --color-muted: #5C6066;
  --color-success: #1A9E5C;
  --color-warning: #F5C518;
  --color-error: #D93025;
  --color-console: #1B1E24;
  --color-console-raised: #262A32;
  --color-console-line: #363B45;
  --color-console-groove: #101216;
  --color-console-muted: #9BA1AB;
  --color-console-text: #EAECEF;
  --color-flag-white: #F4F5F6;
  --color-flag-red: #CE2E2E;
  --color-flag-blue: #2F4C9E;
  --color-overlay: rgba(21, 23, 27, 0.38);
  --color-accent-soft: rgba(235, 94, 40, 0.1);
  --color-warning-soft: rgba(245, 197, 24, 0.16);
  --color-focus: rgba(235, 94, 40, 0.24);
  --font-display: 'Inter', 'Noto Sans SC', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', Consolas, monospace;
  --radius-xs: 4px;
  --radius-sm: 7px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --content-wide: 1360px;
  --content-main: 1120px;
  --content-prose: 760px;
  --gutter: clamp(16px, 3vw, 40px);
  --header-height: 68px;
  --section-space: clamp(68px, 9vw, 124px);
  --toc-offset: 82px;
  --ease-standard: cubic-bezier(.2, .75, .25, 1);
  --duration-fast: 150ms;
  --duration-reveal: 560ms;
}

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

html {
  min-width: 320px;
  scroll-behavior: smooth;
  background: var(--color-canvas);
  color: var(--color-ink);
  font-family: var(--font-body);
  -webkit-text-size-adjust: 100%;
}

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);
  line-height: 1.65;
  -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;
}

button {
  border: 0;
}

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

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

ul,
ol {
  padding-left: 1.25rem;
}

nav ul,
.footer-list,
.tag-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

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

code {
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  padding: 18px;
  border: 1px solid var(--color-console-line);
  border-radius: var(--radius-sm);
  background: var(--color-console);
  color: var(--color-console-text);
  line-height: 1.7;
  -webkit-overflow-scrolling: touch;
}

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

table {
  border-collapse: collapse;
}

th,
td {
  text-align: left;
}

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

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

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

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

.prose {
  width: 100%;
  max-width: var(--content-prose);
  min-width: 0;
}

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

.section-tight {
  padding-top: clamp(44px, 6vw, 76px);
  padding-bottom: clamp(44px, 6vw, 76px);
}

.section-head {
  max-width: 760px;
  margin-bottom: clamp(30px, 5vw, 54px);
}

.eyebrow {
  margin-bottom: 12px;
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .11em;
  text-transform: uppercase;
}

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

h1,
.hero-title {
  margin-bottom: 0;
  font-size: clamp(52px, 5.2vw, 72px);
  font-weight: 900;
  letter-spacing: -.02em;
  line-height: 1.1;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(34px, 4vw, 52px);
  font-weight: 900;
  letter-spacing: -.018em;
  line-height: 1.14;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(22px, 2.5vw, 30px);
  font-weight: 800;
  line-height: 1.25;
}

h4 {
  margin-bottom: 8px;
  font-size: 18px;
  font-weight: 800;
}

.lead {
  color: var(--color-muted);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.7;
}

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

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

.nowrap-term {
  white-space: nowrap;
}

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

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

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

.badge,
.chip {
  display: inline-flex;
  max-width: 100%;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  text-overflow: ellipsis;
  white-space: nowrap;
}

.badge {
  padding: 6px 12px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 12px;
}

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

.badge-warn {
  border-color: var(--color-warning);
  background: var(--color-warning);
  color: var(--color-ink);
}

.badge-accent {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-canvas);
}

.chip {
  padding: 6px 11px;
  color: var(--color-ink);
  font-size: 13px;
}

.chip svg,
.icon-lock {
  flex-shrink: 0;
}

.button,
.btn-primary,
.btn-secondary,
.btn-dark {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border: 1px solid transparent;
  border-radius: 9px;
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 750;
  line-height: 1.2;
  text-align: center;
  transition:
    color var(--duration-fast),
    background var(--duration-fast),
    border-color var(--duration-fast),
    transform var(--duration-fast);
}

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

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

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

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

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

.button:active,
.btn-primary:active,
.btn-secondary:active,
.btn-dark:active {
  transform: translateY(1px);
}

.button[aria-disabled="true"],
.button:disabled {
  cursor: not-allowed;
  opacity: .55;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
}

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

.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);
}

.header-inner {
  width: 100%;
  max-width: var(--content-wide);
  min-height: var(--header-height);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 30px;
}

.brandmark {
  display: inline-flex;
  min-width: 0;
  flex-shrink: 0;
  align-items: center;
  gap: 9px;
}

.brandmark img {
  width: 26px;
  height: 26px;
  flex-shrink: 0;
}

.brand-word {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 900;
  letter-spacing: -.01em;
}

.brand-local {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 600;
}

.desktop-nav {
  display: flex;
  min-width: 0;
  align-items: center;
  gap: clamp(14px, 1.8vw, 27px);
}

.desktop-nav a {
  color: var(--color-muted);
  font-size: 14px;
  font-weight: 520;
  white-space: nowrap;
  transition: color var(--duration-fast);
}

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

.desktop-nav a.is-active {
  font-weight: 750;
}

.header-tools {
  position: relative;
  margin-left: auto;
  display: flex;
  flex-shrink: 0;
  align-items: center;
  gap: 12px;
}

.login-button {
  display: inline-flex;
  min-height: 38px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-line-strong);
  border-radius: var(--radius-sm);
  padding: 8px 19px;
  color: var(--color-ink);
  font-size: 14px;
  font-weight: 650;
  white-space: nowrap;
}

.login-button:hover {
  border-color: var(--color-ink);
}

.language-wrap {
  position: relative;
}

.language-button {
  min-height: 38px;
  padding: 7px 8px;
  background: transparent;
  color: var(--color-muted);
  font-size: 13px;
  white-space: nowrap;
}

.language-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 120;
  display: none;
  min-width: 156px;
  padding: 7px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-canvas);
}

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

.language-menu a {
  display: block;
  min-height: 40px;
  padding: 9px 11px;
  border-radius: var(--radius-xs);
  font-size: 13px;
}

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

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

.menu-button-lines,
.menu-button-lines::before,
.menu-button-lines::after {
  width: 20px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: var(--color-ink);
}

.menu-button-lines {
  position: relative;
}

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

.menu-button-lines::before {
  top: -6px;
}

.menu-button-lines::after {
  top: 6px;
}

.mobile-nav {
  position: absolute;
  top: 100%;
  right: 0;
  left: 0;
  z-index: 115;
  display: none;
  max-height: calc(100dvh - var(--header-height));
  overflow-y: auto;
  overscroll-behavior: contain;
  border-top: 1px solid var(--color-line);
  border-bottom: 1px solid var(--color-line);
  background: var(--color-canvas);
  -webkit-overflow-scrolling: touch;
}

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

.mobile-nav-inner {
  padding: 8px var(--gutter) 18px;
}

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 48px;
  align-items: center;
  border-bottom: 1px solid var(--color-line);
  color: var(--color-muted);
  font-weight: 650;
}

.mobile-nav a.is-active {
  color: var(--color-accent-dark);
}

.mobile-language-label {
  margin: 18px 0 4px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
}

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

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

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

.footer-grid {
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding: 62px var(--gutter) 42px;
  display: grid;
  grid-template-columns: minmax(240px, 1.4fr) repeat(3, minmax(150px, 1fr));
  gap: 48px;
}

.footer-brand p {
  max-width: 360px;
  margin-top: 18px;
  color: var(--color-muted);
  font-size: 14px;
}

.footer-title {
  margin-bottom: 15px;
  font-size: 13px;
  font-weight: 800;
}

.footer-list {
  display: grid;
  gap: 9px;
}

.footer-list a {
  color: var(--color-muted);
  font-size: 13px;
}

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

.footer-legal {
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding: 20px var(--gutter) 28px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 22px;
  border-top: 1px solid var(--color-line);
  color: var(--color-muted);
  font-size: 12px;
}

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

.prose > * {
  max-width: 100%;
}

.prose h2,
.prose h3 {
  scroll-margin-top: var(--toc-offset);
}

.prose p,
.prose li {
  color: var(--color-muted);
}

.prose strong {
  color: var(--color-ink);
}

.prose a {
  color: var(--color-accent-dark);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.prose blockquote {
  margin-inline: 0;
}

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

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

@media (max-width: 1180px) {
  .desktop-nav {
    gap: 14px;
  }

  .desktop-nav a {
    font-size: 13px;
  }

  .brand-local {
    display: none;
  }
}

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

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

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

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

@media (max-width: 768px) {
  h1,
  .hero-title {
    font-size: clamp(28px, 9.8vw, 40px);
    letter-spacing: -.018em;
  }

  h2 {
    font-size: clamp(30px, 8vw, 40px);
  }

  .section {
    padding-top: 72px;
    padding-bottom: 72px;
  }
}

@media (max-width: 640px) {
  :root {
    --gutter: 18px;
  }

  .header-inner {
    gap: 8px;
  }

  .brand-local {
    display: none;
  }

  .language-button {
    display: none;
  }

  .login-button {
    min-height: 36px;
    padding-inline: 14px;
  }

  .button-row,
  .button-row .button,
  .button-row .btn-primary,
  .button-row .btn-secondary {
    width: 100%;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 34px;
    padding-top: 46px;
  }

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

  .decor-orb,
  .decor-disc,
  .decor-watermark {
    display: none;
  }
}

@media (max-width: 360px) {
  :root {
    --gutter: 16px;
  }

  .brand-word {
    font-size: 17px;
  }

  .login-button {
    padding-inline: 11px;
  }
}

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

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

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