:root {
  --color-bg: #0C0D12;
  --color-panel: #13151D;
  --color-panel-raised: #1A1D28;
  --color-border: #272B3A;
  --color-accent: #7C86FF;
  --color-accent-deep: #5560E8;
  --color-text: #EDEEF4;
  --color-text-muted: #9CA1B5;
  --color-success: #4ADE9C;
  --color-warning: #F5C155;
  --color-error: #F26D6D;
  --color-white: #FFFFFF;
  --color-black: #000000;
  --color-dot-page: rgba(156, 161, 181, 0.07);
  --color-dot-canvas: rgba(156, 161, 181, 0.12);
  --color-accent-line: rgba(124, 134, 255, 0.55);
  --color-accent-glow: rgba(124, 134, 255, 0.38);
  --color-accent-glow-soft: rgba(124, 134, 255, 0.16);
  --color-shadow: rgba(0, 0, 0, 0.45);
  --color-overlay: rgba(12, 13, 18, 0.76);
  --color-flag-red: #D8434E;
  --color-flag-blue: #46508F;
  --color-flag-gold: #F5C155;
  --color-flag-white: #F4F5F8;
  --color-flag-ink: #14151A;
  --font-display: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, 'Courier New', monospace;
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-pill: 999px;
  --header-height: 68px;
  --content-width: 1280px;
  --reading-width: 780px;
  --gutter: 40px;
  --section-space: 104px;
  --focus-width: 2px;
  --shadow-panel: 0 24px 64px var(--color-shadow);
  --shadow-card: 0 10px 28px var(--color-shadow);
  --transition-fast: 180ms ease;
  --transition-reveal: 620ms cubic-bezier(0.22, 1, 0.36, 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: 0;
  min-height: 100vh;
  margin: 0;
  overflow-x: clip;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

body::before {
  position: fixed;
  z-index: -1;
  inset: 0;
  background-image: radial-gradient(circle, var(--color-dot-page) 1px, transparent 1px);
  background-size: 24px 24px;
  content: "";
  pointer-events: none;
}

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

img {
  height: auto;
}

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

button {
  cursor: pointer;
}

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

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

p:last-child,
ul:last-child,
ol:last-child,
blockquote:last-child,
pre:last-child {
  margin-bottom: 0;
}

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

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

h1,
h2,
h3 {
  display: block;
}

h1 {
  margin-bottom: 22px;
  font-size: clamp(52px, 5vw, 72px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.12;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(34px, 3.4vw, 48px);
  font-weight: 750;
  letter-spacing: -0.01em;
  line-height: 1.16;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(21px, 2vw, 28px);
  font-weight: 700;
  line-height: 1.3;
}

h4 {
  margin-bottom: 10px;
  font-size: 18px;
  line-height: 1.4;
}

strong {
  color: var(--color-text);
  font-weight: 650;
}

small {
  color: var(--color-text-muted);
}

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

:not(pre) > code {
  padding: 0.12em 0.38em;
  overflow-wrap: anywhere;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-panel-raised);
  color: var(--color-text);
  font-size: 0.88em;
}

pre {
  max-width: 100%;
  padding: 20px;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel);
  color: var(--color-text);
  font-family: var(--font-mono);
  line-height: 1.65;
  tab-size: 2;
  -webkit-overflow-scrolling: touch;
}

pre code {
  padding: 0;
  border: 0;
  background: transparent;
  white-space: pre;
}

hr {
  height: 1px;
  margin: 48px 0;
  border: 0;
  background: var(--color-border);
}

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

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

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

.accent-text,
.hl {
  color: var(--color-accent);
  text-shadow: 0 0 26px var(--color-accent-glow-soft);
}

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

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

.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) + var(--gutter));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  position: relative;
  min-width: 0;
  overflow-x: clip;
  padding-top: var(--section-space);
  padding-bottom: var(--section-space);
}

.section-compact {
  padding-top: 64px;
  padding-bottom: 64px;
}

.section-head {
  max-width: 760px;
  margin-bottom: 42px;
}

.section-head p {
  color: var(--color-text-muted);
  font-size: 18px;
}

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

.panel {
  padding: 28px;
}

.card {
  padding: 24px;
  box-shadow: var(--shadow-card);
}

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

.eyebrow,
.badge,
.fact-chip {
  display: inline-flex;
  max-width: 100%;
  align-items: center;
  gap: 9px;
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
}

.eyebrow {
  min-height: 30px;
  padding: 4px 14px;
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  font-size: 12px;
  letter-spacing: 0.04em;
}

.eyebrow-dot,
.status-dot {
  width: 6px;
  height: 6px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent-glow);
}

.badge,
.fact-chip {
  min-height: 26px;
  padding: 3px 9px;
  overflow: hidden;
  border-radius: var(--radius-sm);
  background: var(--color-panel-raised);
  font-size: 11px;
  letter-spacing: 0.04em;
}

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

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

.button,
.btn-primary,
.btn-ghost,
.btn-login {
  display: inline-flex;
  min-width: 24px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  font-weight: 700;
  line-height: 1.2;
  text-align: center;
  transition:
    border-color var(--transition-fast),
    background var(--transition-fast),
    color var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast);
}

.btn-primary {
  min-height: 48px;
  padding: 0 32px;
  border: 1px solid var(--color-accent-line);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-deep));
  box-shadow: 0 10px 32px var(--color-accent-glow-soft);
  color: var(--color-white);
  font-size: 15px;
}

.btn-primary:hover {
  box-shadow: 0 14px 40px var(--color-accent-glow);
  transform: translateY(-1px);
}

.btn-ghost {
  min-height: 48px;
  padding: 0 28px;
  border: 1px solid var(--color-border);
  background: var(--color-panel);
  color: var(--color-text);
  font-size: 15px;
}

.btn-ghost:hover {
  border-color: var(--color-accent);
  background: var(--color-panel-raised);
}

.btn-login {
  min-height: 36px;
  padding: 0 18px;
  border: 1px solid var(--color-border);
  background: var(--color-panel);
  color: var(--color-text);
  font-size: 13px;
}

.btn-login:hover {
  border-color: var(--color-accent);
  background: var(--color-panel-raised);
}

.button[aria-disabled="true"],
.button:disabled,
.btn-primary:disabled,
.btn-ghost:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.button-row,
.cta-row {
  display: flex;
  min-width: 0;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
}

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

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

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

.site-top {
  position: relative;
  z-index: 50;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
}

.site-top-inner {
  display: flex;
  height: var(--header-height);
  align-items: center;
  gap: 36px;
}

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

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

.site-brand-name {
  color: var(--color-text);
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: 0.02em;
}

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

.desktop-nav {
  display: flex;
  min-width: 0;
  height: var(--header-height);
  flex: 1 1 auto;
  align-items: stretch;
  gap: 2px;
}

.desktop-nav a {
  position: relative;
  display: flex;
  min-width: 24px;
  align-items: center;
  padding-inline: 13px;
  color: var(--color-text-muted);
  font-size: 14px;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

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

.desktop-nav a.is-current::after {
  position: absolute;
  right: 13px;
  bottom: -1px;
  left: 13px;
  height: 2px;
  border-radius: var(--radius-xs);
  background: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent-glow);
  content: "";
}

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

.language-menu {
  position: relative;
}

.language-toggle {
  display: inline-flex;
  min-width: 24px;
  min-height: 44px;
  align-items: center;
  gap: 7px;
  padding: 0 5px;
  border: 0;
  background: transparent;
  color: var(--color-text-muted);
  font-size: 13px;
}

.language-toggle:hover {
  color: var(--color-text);
}

.language-popover {
  position: absolute;
  z-index: 70;
  top: calc(100% + 8px);
  right: 0;
  width: 172px;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel-raised);
  box-shadow: var(--shadow-panel);
}

.language-popover[hidden] {
  display: none;
}

.language-popover a {
  display: flex;
  min-height: 42px;
  align-items: center;
  padding: 8px 11px;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: 13px;
}

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

.menu-toggle {
  display: none;
  min-width: 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);
  color: var(--color-text);
}

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  width: 18px;
  height: 1px;
  background: currentColor;
}

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

.menu-toggle-lines::before,
.menu-toggle-lines::after {
  position: absolute;
  left: 0;
  content: "";
  transition: transform var(--transition-fast), top var(--transition-fast);
}

.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 {
  top: 0;
  transform: rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::after {
  top: 0;
  transform: rotate(-45deg);
}

.mobile-drawer {
  display: none;
}

.mobile-veil {
  display: none;
}

.site-footer {
  position: relative;
  z-index: 2;
  overflow-x: clip;
  border-top: 1px solid var(--color-border);
  background: var(--color-panel);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.15fr 1fr 1fr 0.8fr;
  gap: 42px;
  padding-top: 64px;
  padding-bottom: 52px;
}

.footer-brand {
  max-width: 330px;
}

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

.footer-title {
  margin-bottom: 14px;
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

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

.footer-links a {
  display: inline-flex;
  width: fit-content;
  min-height: 28px;
  align-items: center;
  color: var(--color-text-muted);
  font-size: 13px;
}

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

.footer-bottom {
  display: flex;
  min-height: 68px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 11px;
}

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

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

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

.prose > * + * {
  margin-top: 1.25em;
}

.prose h2 {
  margin-top: 2.2em;
  color: var(--color-text);
}

.prose h3 {
  margin-top: 1.8em;
  color: var(--color-text);
}

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

.prose li + li {
  margin-top: 0.45em;
}

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

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

@media (max-width: 1180px) {
  .desktop-nav a {
    padding-inline: 9px;
    font-size: 13px;
  }

  .site-top-inner {
    gap: 22px;
  }
}

@media (max-width: 1040px) {
  .desktop-nav {
    display: none;
  }

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

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

  .language-menu {
    display: none;
  }

  .mobile-veil {
    position: fixed;
    z-index: 48;
    inset: var(--header-height) 0 0;
    background: var(--color-overlay);
  }

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

  .mobile-drawer {
    position: absolute;
    z-index: 55;
    top: var(--header-height);
    right: 0;
    left: 0;
    max-height: calc(100dvh - var(--header-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-panel);
    box-shadow: var(--shadow-panel);
    -webkit-overflow-scrolling: touch;
  }

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

  .mobile-drawer-inner {
    padding-top: 12px;
    padding-bottom: 20px;
  }

  .mobile-drawer-group {
    display: grid;
  }

  .mobile-drawer a {
    display: flex;
    width: 100%;
    min-height: 48px;
    align-items: center;
    padding: 11px 12px;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-muted);
  }

  .mobile-drawer a.is-current,
  .mobile-drawer a:hover {
    color: var(--color-text);
  }

  .mobile-language-title {
    margin: 22px 12px 7px;
    color: var(--color-accent);
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: 0.14em;
  }
}

@media (max-width: 768px) {
  :root {
    --gutter: 22px;
    --section-space: 76px;
  }

  h1 {
    font-size: clamp(28px, 9vw, 40px);
    line-height: 1.14;
  }

  h2 {
    font-size: clamp(28px, 7vw, 38px);
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }
}

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

  body {
    font-size: 15px;
  }

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

  .site-brand-name {
    font-size: 16px;
  }

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

  .section {
    padding-top: 64px;
    padding-bottom: 64px;
  }

  .panel,
  .card {
    padding: 20px;
  }

  .button-row,
  .cta-row {
    align-items: stretch;
  }

  .button-row > *,
  .cta-row > * {
    flex: 1 1 145px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-brand {
    grid-column: auto;
  }

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

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

@media (max-width: 380px) {
  :root {
    --gutter: 16px;
  }

  .site-brand img {
    width: 26px;
    height: 26px;
  }

  .header-tools {
    gap: 7px;
  }

  .btn-login {
    padding-inline: 10px;
  }
}

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

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

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

  .btn-primary:hover {
    transform: none;
  }
}