:root {
  --color-bg: #F8F1E4;
  --color-panel: #FFFCF6;
  --color-panel-soft: #F1E8D8;
  --color-border: #E4D8C4;
  --color-accent: #8F2D6E;
  --color-accent-dark: #6E1F53;
  --color-text: #2B211F;
  --color-muted: #6F625C;
  --color-success: #2F7D4F;
  --color-warning: #C9862B;
  --color-error: #B8382E;
  --color-sun: #E9A23B;
  --color-dusk: #7A6A8C;
  --color-white-alpha: rgba(255, 252, 246, 0.78);
  --color-paper-alpha: rgba(248, 241, 228, 0.92);
  --color-accent-shadow: rgba(143, 45, 110, 0.55);
  --color-success-ring: rgba(47, 125, 79, 0.16);
  --color-sun-soft: rgba(233, 162, 59, 0.2);
  --color-sun-faint: rgba(233, 162, 59, 0.08);
  --color-sun-glow: rgba(233, 162, 59, 0.34);
  --color-dusk-soft: rgba(122, 106, 140, 0.22);
  --color-dusk-faint: rgba(122, 106, 140, 0.08);
  --color-dusk-glow: rgba(122, 106, 140, 0.3);
  --color-ink-04: rgba(43, 33, 31, 0.04);
  --color-ink-06: rgba(43, 33, 31, 0.06);
  --color-ink-10: rgba(43, 33, 31, 0.1);
  --color-ink-14: rgba(43, 33, 31, 0.14);
  --color-ink-18: rgba(43, 33, 31, 0.18);
  --font-display: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', system-ui, sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Menlo, Consolas, 'Liberation Mono', monospace;
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 14px;
  --radius-pill: 999px;
  --header-height: 72px;
  --content-width: 1360px;
  --reading-width: 820px;
  --gutter: clamp(16px, 3vw, 40px);
  --section-space: clamp(64px, 9vw, 124px);
  --grid-gap: 20px;
  --focus-ring: 2px solid var(--color-accent);
  --shadow-card: 0 1px 2px var(--color-ink-06), 0 8px 20px -10px var(--color-ink-10);
  --shadow-window: 0 4px 8px var(--color-ink-10), 0 24px 40px -12px var(--color-ink-18), 0 64px 90px -30px var(--color-ink-14);
  --ease-standard: cubic-bezier(0.2, 0.7, 0.2, 1);
  --toc-offset: 132px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 16px);
  -webkit-text-size-adjust: 100%;
}

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 320px;
  margin: 0;
  overflow-x: clip;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  position: relative;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0.05;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size: 180px 180px;
}

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

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

img {
  height: auto;
}

svg {
  display: block;
  flex-shrink: 0;
}

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

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

button {
  cursor: pointer;
}

a,
button,
summary,
[role="tab"],
[tabindex] {
  -webkit-tap-highlight-color: transparent;
}

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

p,
ul,
ol,
blockquote,
figure {
  margin-top: 0;
}

ul,
ol {
  padding-left: 1.3em;
}

nav ul,
nav ol,
.clean-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

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

h1 {
  margin: 0;
  font-size: clamp(52px, 5vw, 72px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h2 {
  margin: 0 0 20px;
  font-size: clamp(34px, 4vw, 52px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.018em;
}

h3 {
  margin: 0 0 12px;
  font-size: clamp(22px, 2.4vw, 30px);
  line-height: 1.25;
}

p {
  margin-bottom: 1em;
}

strong {
  font-weight: 700;
}

code,
kbd,
samp {
  font-family: var(--font-mono);
  overflow-wrap: anywhere;
}

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

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

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

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

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

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

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

.section-compact {
  padding-top: clamp(42px, 6vw, 76px);
  padding-bottom: clamp(42px, 6vw, 76px);
  overflow-x: clip;
}

.section-head {
  max-width: 760px;
  margin-bottom: 36px;
}

.section-kicker {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.section-kicker::before {
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--color-accent);
  content: "";
  flex-shrink: 0;
}

.lead {
  max-width: 760px;
  color: var(--color-muted);
  font-size: clamp(18px, 2vw, 21px);
}

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

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

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

.panel,
.card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
}

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

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

.card:hover {
  transform: translateY(-2px);
}

.card,
.btn,
.nav-link {
  transition: transform 0.22s var(--ease-standard), color 0.18s var(--ease-standard), background-color 0.18s var(--ease-standard), border-color 0.18s var(--ease-standard), box-shadow 0.22s var(--ease-standard);
}

.grid {
  display: grid;
  gap: var(--grid-gap);
}

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

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.btn {
  display: inline-flex;
  min-width: 24px;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-size: 15.5px;
  font-weight: 700;
  line-height: 1;
  text-align: center;
}

.btn svg {
  width: 16px;
  height: 16px;
}

.btn-primary {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-panel);
  box-shadow: 0 8px 18px -8px var(--color-accent-shadow);
}

.btn-primary:hover {
  border-color: var(--color-accent-dark);
  background: var(--color-accent-dark);
  transform: translateY(-1px);
}

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

.btn-secondary:hover,
.btn-ghost:hover {
  border-color: var(--color-muted);
}

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

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

.btn[aria-disabled="true"],
.btn:disabled {
  cursor: not-allowed;
  opacity: 0.5;
  transform: none;
}

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

.badge,
.chip,
.fact-chip {
  display: inline-flex;
  min-height: 28px;
  max-width: 100%;
  align-items: center;
  gap: 7px;
  padding: 4px 10px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-muted);
  font-size: 12px;
  line-height: 1.4;
  text-overflow: ellipsis;
}

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

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

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-success);
  flex-shrink: 0;
}

.reveal {
  transition: opacity 0.65s var(--ease-standard), transform 0.65s var(--ease-standard);
}

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

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

.site-header {
  position: relative;
  z-index: 40;
  min-height: var(--header-height);
}

.site-header-inner {
  display: flex;
  min-height: var(--header-height);
  align-items: center;
  gap: 28px;
}

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

.brand-logo,
.brand-mark {
  width: 30px;
  height: 30px;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: 0.01em;
}

.brand-name::after {
  color: var(--color-accent);
  content: ".";
}

.brand-local {
  color: var(--color-muted);
  font-size: 14px;
  font-weight: 500;
}

.desktop-nav {
  display: flex;
  flex: 1 1 auto;
  justify-content: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 13px;
  border-radius: var(--radius-sm);
  color: var(--color-muted);
  font-size: 15px;
}

.nav-link:hover {
  background: var(--color-panel-soft);
  color: var(--color-text);
}

.nav-link[aria-current="page"] {
  color: var(--color-text);
  font-weight: 700;
}

.nav-link[aria-current="page"]::after {
  width: 5px;
  height: 5px;
  margin-left: 2px;
  border-radius: 50%;
  background: var(--color-accent);
  content: "";
}

.nav-more-button {
  border: 0;
  background: transparent;
}

.nav-caret {
  color: var(--color-muted);
  font-size: 11px;
}

.nav-menu {
  position: absolute;
  top: calc(100% + 7px);
  left: 0;
  z-index: 44;
  min-width: 190px;
  padding: 6px;
  visibility: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
  opacity: 0;
  transform: translateY(-4px);
  transition: opacity 0.18s var(--ease-standard), transform 0.18s var(--ease-standard), visibility 0.18s;
}

.nav-item-more:hover .nav-menu,
.nav-item-more:focus-within .nav-menu {
  visibility: visible;
  opacity: 1;
  transform: none;
}

.nav-menu a {
  display: flex;
  min-height: 42px;
  align-items: center;
  padding: 8px 11px;
  border-radius: var(--radius-sm);
  font-size: 14px;
}

.nav-menu a:hover {
  background: var(--color-panel-soft);
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

.language-picker {
  position: relative;
}

.language-button {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 7px 10px;
  border: 0;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-muted);
  font-size: 14px;
}

.language-button:hover {
  background: var(--color-panel-soft);
  color: var(--color-text);
}

.language-menu {
  position: absolute;
  top: calc(100% + 7px);
  right: 0;
  z-index: 45;
  min-width: 152px;
  padding: 6px;
  display: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
}

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

.language-menu a {
  display: flex;
  min-height: 40px;
  align-items: center;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
  font-size: 13px;
}

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

.header-login {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  padding: 8px 17px;
  border: 1px solid var(--color-text);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-text);
  font-size: 14px;
  font-weight: 700;
}

.header-login:hover {
  background: var(--color-text);
  color: var(--color-panel);
}

.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-border);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
}

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  width: 19px;
  height: 2px;
  border-radius: var(--radius-pill);
  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: var(--header-height);
  right: var(--gutter);
  left: var(--gutter);
  z-index: 48;
  display: none;
  max-height: calc(100dvh - var(--header-height) - 12px);
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel);
  box-shadow: var(--shadow-window);
}

.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-sm);
}

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

.mobile-language-label {
  margin: 12px 12px 5px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
}

.mobile-nav-separator {
  margin: 8px 0;
  border-top: 1px solid var(--color-border);
}

.nav-veil {
  position: fixed;
  inset: var(--header-height) 0 0;
  z-index: 35;
  display: none;
  background: var(--color-ink-18);
}

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

.site-footer {
  position: relative;
  z-index: 1;
  padding-top: 64px;
  padding-bottom: 28px;
  border-top: 1px solid var(--color-border);
  background: var(--color-panel-soft);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(240px, 1.35fr) repeat(3, minmax(150px, 0.75fr));
  gap: clamp(28px, 5vw, 68px);
}

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

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

.footer-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links li + li {
  margin-top: 7px;
}

.footer-links a {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  color: var(--color-muted);
  font-size: 14px;
}

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 48px;
  padding-top: 20px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 13px;
}

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

.prose {
  color: var(--color-text);
  font-size: 17px;
}

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

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

.prose p,
.prose li {
  overflow-wrap: break-word;
}

.prose a:not(.btn) {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

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

.prose blockquote {
  margin-inline: 0;
}

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

@media (max-width: 1100px) {
  .desktop-nav {
    display: none;
  }

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

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

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

@media (max-width: 768px) {
  h1 {
    font-size: clamp(28px, 9.8vw, 40px);
  }

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

  .section,
  .section-compact {
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .grid-4,
  .grid-3,
  .grid-2 {
    grid-template-columns: minmax(0, 1fr);
  }

  .language-picker {
    display: none;
  }

  .site-header-inner {
    gap: 10px;
  }

  .header-login {
    min-height: 38px;
    padding-inline: 14px;
  }

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

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

@media (max-width: 640px) {
  .no-break {
    white-space: normal;
  }

  .decorative-tilt,
  .tilt-card,
  [data-tilt] {
    transform: none;
  }

  .brand-local {
    display: none;
  }

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

  .brand-logo,
  .brand-mark {
    width: 28px;
    height: 28px;
  }

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

  .prose {
    font-size: 16px;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto;
    animation: none !important;
    transition: none !important;
  }

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