:root {
  --color-page: #F7F1E1;
  --color-panel: #FFFCF2;
  --color-panel-soft: #EFE6CF;
  --color-line: #DFD3B6;
  --color-accent: #35782B;
  --color-accent-deep: #275C20;
  --color-text: #2B241A;
  --color-text-soft: #6E6350;
  --color-success: #337E4C;
  --color-warning: #B07B18;
  --color-error: #B3392B;
  --color-flag-red: #C4382E;
  --color-flag-blue: #31518E;
  --color-flag-white: #FDFBF4;
  --color-flag-yellow: #E7B83F;
  --color-focus: #35782B;
  --color-shadow-soft: color-mix(in srgb, var(--color-text) 6%, transparent);
  --color-shadow-mid: color-mix(in srgb, var(--color-text) 13%, transparent);
  --color-shadow-button: color-mix(in srgb, var(--color-accent) 23%, transparent);
  --color-grid: color-mix(in srgb, var(--color-line) 60%, transparent);
  --color-paper-thread: color-mix(in srgb, var(--color-text) 2%, transparent);
  --color-paper-light: color-mix(in srgb, var(--color-panel) 8%, transparent);
  --font-display: "Inter", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Inter", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --radius-xs: 6px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --shadow-panel: 0 1px 2px var(--color-shadow-soft), 0 3px 8px var(--color-shadow-soft), 0 22px 52px var(--color-shadow-mid);
  --shadow-button: 0 1px 2px var(--color-shadow-button), 0 8px 20px var(--color-shadow-button);
  --content-max: 1320px;
  --reading-max: 780px;
  --header-height: 68px;
  --gutter: clamp(16px, 3vw, 32px);
  --section-space: clamp(64px, 8vw, 112px);
  --toc-offset: 84px;
  --transition-fast: 180ms ease;
  --transition-reveal: 620ms cubic-bezier(.22, .8, .36, 1);
}

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

html {
  min-width: 320px;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 16px);
  background: var(--color-page);
}

html.nav-open {
  overflow: hidden;
}

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

body::before,
body::after {
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  content: "";
}

body::before {
  background-image:
    linear-gradient(var(--color-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
  background-size: 56px 56px;
  opacity: .22;
}

body::after {
  z-index: -1;
  background-image:
    repeating-linear-gradient(63deg, var(--color-paper-thread) 0 1px, transparent 1px 5px),
    repeating-linear-gradient(-27deg, var(--color-paper-light) 0 1px, transparent 1px 4px);
}

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

img {
  height: auto;
}

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

button,
summary,
select {
  cursor: pointer;
}

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

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

ul,
ol {
  padding: 0;
}

ul {
  list-style: none;
}

table {
  border-collapse: collapse;
}

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

code {
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

button,
a,
summary,
select,
input,
textarea,
[role="tab"] {
  touch-action: manipulation;
}

a:focus-visible,
button:focus-visible,
summary:focus-visible,
select:focus-visible,
input:focus-visible,
textarea:focus-visible,
[role="tab"]:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
}

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

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

.section-tight {
  padding-top: clamp(40px, 5vw, 68px);
  padding-bottom: clamp(40px, 5vw, 68px);
}

.grid {
  display: grid;
  gap: 24px;
}

.grid > *,
.flex-row > * {
  min-width: 0;
}

.flex-row {
  display: flex;
  align-items: center;
  gap: 16px;
}

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

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

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

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

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  color: var(--color-text-soft);
  font-size: 13px;
  letter-spacing: .14em;
}

.eyebrow::before {
  width: 26px;
  height: 3px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  content: "";
}

.eyebrow .mono {
  color: var(--color-accent);
  font-size: 12px;
  letter-spacing: .08em;
}

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

h1,
.display-title {
  font-size: clamp(52px, 5vw, 72px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -.015em;
}

h2 {
  font-size: clamp(34px, 4vw, 52px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -.012em;
}

h3 {
  font-size: clamp(22px, 2.3vw, 30px);
  font-weight: 800;
  line-height: 1.24;
}

h4 {
  font-size: 18px;
  font-weight: 800;
  line-height: 1.35;
}

.lead {
  max-width: 42em;
  color: var(--color-text-soft);
  font-size: clamp(17px, 1.8vw, 21px);
  line-height: 1.7;
}

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

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

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

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

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

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

.prose ul {
  list-style: disc;
}

.prose li + li {
  margin-top: .55em;
}

.prose pre {
  padding: 18px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-panel-soft);
}

.btn,
.btn-primary,
.btn-secondary,
.btn-login,
.btn-quiet {
  display: inline-flex;
  min-width: 24px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 700;
  line-height: 1.2;
  text-align: center;
  transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

.btn-primary {
  border: 1px solid var(--color-accent-deep);
  color: var(--color-panel);
  background: var(--color-accent);
  box-shadow: var(--shadow-button);
}

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

.btn-secondary {
  border: 1.5px solid var(--color-line);
  color: var(--color-text);
  background: transparent;
}

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

.btn-login {
  min-height: 40px;
  padding: 8px 20px;
  border: 1.5px solid var(--color-accent);
  border-radius: var(--radius-sm);
  color: var(--color-accent);
  background: var(--color-panel);
  font-size: 14px;
}

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

.btn-quiet {
  border: 1px solid transparent;
  color: var(--color-text-soft);
  background: transparent;
}

.btn-quiet:hover {
  color: var(--color-text);
  background: var(--color-panel-soft);
}

.btn[aria-disabled="true"],
.btn:disabled {
  cursor: not-allowed;
  opacity: .56;
  transform: none;
}

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

.badge,
.fact-chip,
.tag {
  display: inline-flex;
  max-width: 100%;
  min-height: 28px;
  align-items: center;
  gap: 7px;
  padding: 5px 10px;
  overflow: hidden;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  color: var(--color-text-soft);
  background: var(--color-panel);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.35;
}

.badge-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--color-success);
}

.badge-accent {
  border-color: color-mix(in srgb, var(--color-accent) 34%, transparent);
  color: var(--color-accent-deep);
  background: color-mix(in srgb, var(--color-accent) 9%, var(--color-panel));
}

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

.card {
  padding: clamp(20px, 3vw, 30px);
  box-shadow: 0 1px 2px var(--color-shadow-soft);
}

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

.divider {
  height: 1px;
  border: 0;
  background: var(--color-line);
}

.site-header {
  position: relative;
  z-index: 40;
  border-bottom: 1px solid var(--color-line);
  background: color-mix(in srgb, var(--color-panel) 82%, var(--color-page));
}

.header-inner {
  width: 100%;
  max-width: var(--content-max);
  height: var(--header-height);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 26px;
}

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

.brand-logo {
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  border-radius: var(--radius-sm);
}

.brand-word {
  color: var(--color-text);
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 900;
  letter-spacing: .02em;
}

.brand-local {
  color: var(--color-text-soft);
  font-size: 14px;
  font-weight: 600;
}

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

.desktop-nav ul {
  display: flex;
  align-items: center;
}

.desktop-nav li {
  display: flex;
  align-items: center;
}

.desktop-nav li + li::before {
  margin-inline: 12px;
  color: var(--color-line);
  font-weight: 800;
  content: "·";
}

.desktop-nav a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  color: var(--color-text-soft);
  font-size: 14px;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

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

.desktop-nav a[aria-current="page"] {
  font-weight: 700;
}

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

.language-picker {
  position: relative;
}

.language-button {
  display: inline-flex;
  min-width: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px;
  border: 0;
  color: var(--color-text-soft);
  background: transparent;
  font-size: 13px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 44;
  width: 168px;
  padding: 7px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-panel);
  box-shadow: var(--shadow-panel);
}

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

.language-menu a {
  display: flex;
  min-height: 44px;
  align-items: center;
  padding: 9px 12px;
  border-radius: var(--radius-xs);
  color: var(--color-text-soft);
  font-size: 14px;
}

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

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

.menu-toggle svg {
  width: 22px;
  height: 22px;
}

.mobile-nav {
  display: none;
}

.mobile-nav[hidden] {
  display: none;
}

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

.mobile-nav ul {
  border-top: 1px solid var(--color-line);
}

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 48px;
  align-items: center;
  padding: 11px 4px;
  border-bottom: 1px solid var(--color-line);
  color: var(--color-text-soft);
}

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

.mobile-languages {
  display: grid;
  margin-top: 10px;
  grid-template-columns: 1fr;
}

.mobile-languages a {
  padding-inline: 4px;
}

.nav-veil {
  position: fixed;
  inset: var(--header-height) 0 0;
  z-index: 30;
  border: 0;
  background: color-mix(in srgb, var(--color-text) 24%, transparent);
}

.nav-veil[hidden] {
  display: none;
}

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

.footer-main {
  display: grid;
  padding-top: 58px;
  padding-bottom: 46px;
  grid-template-columns: minmax(240px, 1.3fr) repeat(3, minmax(150px, 1fr));
  gap: 42px;
}

.footer-brand p {
  max-width: 31em;
  margin-top: 14px;
  color: var(--color-text-soft);
  font-size: 14px;
}

.footer-heading {
  margin-bottom: 15px;
  color: var(--color-text);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: .08em;
}

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

.footer-links a {
  display: inline-flex;
  min-height: 32px;
  align-items: center;
  color: var(--color-text-soft);
  font-size: 14px;
}

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

.footer-bottom {
  display: flex;
  min-height: 66px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-top: 14px;
  padding-bottom: 14px;
  border-top: 1px solid var(--color-line);
  color: var(--color-text-soft);
  font-size: 13px;
}

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

.footer-legal a {
  min-height: 28px;
  display: inline-flex;
  align-items: center;
}

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

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

.reveal.shown {
  opacity: 1;
  transform: translateY(0);
}

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

.icon-fixed,
.status-dot,
.flag-inline,
.platform-icon {
  flex: 0 0 auto;
}

@media (max-width: 1120px) {
  .desktop-nav {
    display: none;
  }

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

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

  .mobile-nav {
    position: absolute;
    top: var(--header-height);
    left: 0;
    z-index: 42;
    display: block;
    width: 100%;
    max-height: calc(100dvh - var(--header-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    border-bottom: 1px solid var(--color-line);
    background: var(--color-panel);
    box-shadow: var(--shadow-panel);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
    --toc-offset: 78px;
  }

  h1,
  .display-title {
    font-size: clamp(28px, 9vw, 40px);
    line-height: 1.12;
    letter-spacing: -.01em;
  }

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

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

  .header-inner {
    gap: 10px;
  }

  .brand-logo {
    width: 32px;
    height: 32px;
  }

  .brand-local {
    display: none;
  }

  .language-picker {
    display: none;
  }

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

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

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

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

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

  .button-row {
    align-items: stretch;
    flex-direction: column;
  }

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

  .btn-login {
    min-width: 64px;
    padding-inline: 13px;
  }

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

  .tilt {
    transform: none;
  }

  .footer-main {
    grid-template-columns: 1fr;
    gap: 30px;
  }

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

@media (max-width: 374px) {
  .brand-logo {
    width: 29px;
    height: 29px;
  }

  .brand-word {
    font-size: 16px;
  }

  .header-tools {
    gap: 6px;
  }

  .btn-login {
    min-width: 58px;
    padding-inline: 10px;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto;
    transition-duration: 0s;
    animation-duration: 0s;
    animation-iteration-count: 1;
  }

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