:root {
  --color-bg: #FFFFFF;
  --color-panel: #F6FAF8;
  --color-panel-strong: #EDF4F1;
  --color-border: #DFE8E4;
  --color-accent: #1D9F76;
  --color-accent-dark: #14775A;
  --color-text: #17201C;
  --color-muted: #5D6B65;
  --color-success: #1D9F76;
  --color-warning: #EEB020;
  --color-error: #D64949;
  --color-flag-red: #CC5F5A;
  --color-flag-blue: #51749B;
  --color-white-soft: #FAFCFB;
  --color-overlay: rgba(23, 32, 28, .34);
  --color-shadow: rgba(23, 32, 28, .07);
  --color-shadow-soft: rgba(23, 32, 28, .04);
  --color-accent-shadow: rgba(29, 159, 118, .22);
  --font-display: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', -apple-system, sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Courier New', monospace;
  --radius-xs: 6px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --shadow-card: 0 14px 36px var(--color-shadow), 0 2px 6px var(--color-shadow-soft);
  --shadow-button: 0 6px 16px var(--color-accent-shadow);
  --header-height: 68px;
  --content-width: 1288px;
  --reading-width: 780px;
  --gutter: 32px;
  --section-space: 96px;
  --toc-top: 12px;
  --toc-offset: 84px;
  --transition-fast: 150ms ease;
  --transition-normal: 420ms ease;
}

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

html {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

html.nav-open {
  overflow: hidden;
}

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

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:focus-visible,
button:focus-visible,
summary:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid var(--color-accent-shadow);
  outline-offset: 3px;
}

ul,
ol {
  margin-top: 0;
}

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

code {
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  padding: 18px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-panel);
  -webkit-overflow-scrolling: touch;
}

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

.wrap,
.shell {
  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);
}

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

.overflow-guard,
.hero,
.preview-hero,
.promo-block {
  overflow-x: clip;
}

h1,
h2,
h3,
h4 {
  margin: 0 0 .65em;
  color: var(--color-text);
  font-family: var(--font-display);
  line-height: 1.16;
  text-wrap: balance;
}

h1,
.hero-title {
  max-width: 100%;
  font-size: clamp(52px, 5.3vw, 72px);
  font-weight: 900;
  letter-spacing: -.018em;
  line-height: 1.1;
}

h2 {
  font-size: clamp(32px, 3.4vw, 48px);
  font-weight: 850;
  letter-spacing: -.012em;
}

h3 {
  font-size: clamp(22px, 2vw, 28px);
  font-weight: 800;
}

h4 {
  font-size: 18px;
  font-weight: 750;
}

p {
  margin: 0 0 1em;
}

.lead {
  max-width: 760px;
  color: var(--color-muted);
  font-size: clamp(17px, 1.6vw, 21px);
  line-height: 1.75;
}

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

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

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

.eyebrow,
.kicker,
.badge,
.tag {
  display: inline-flex;
  align-items: center;
  max-width: 100%;
  gap: 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.3;
}

.eyebrow,
.kicker {
  padding: 7px 14px;
  letter-spacing: .02em;
}

.badge,
.tag {
  padding: 5px 10px;
  overflow: hidden;
  overflow-wrap: anywhere;
}

.status-dot,
.kicker-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--color-accent);
}

.badge-warning {
  border-color: var(--color-warning);
  background: var(--color-bg);
  color: var(--color-text);
}

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

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

.button,
.btn-primary,
.btn-secondary,
.btn-ghost,
.login-button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  padding: 12px 24px;
  font-weight: 750;
  line-height: 1.25;
  text-align: center;
  transition: background var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

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

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

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

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

.button[aria-disabled="true"],
.button:disabled {
  opacity: .55;
  cursor: not-allowed;
  transform: none;
}

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

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

.card {
  padding: 28px;
  box-shadow: var(--shadow-card);
}

.panel {
  padding: 28px;
  background: var(--color-panel);
}

.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: 24px;
}

.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));
}

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

.header-inner {
  display: flex;
  min-height: var(--header-height);
  align-items: center;
  gap: 34px;
}

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

.brand-logo {
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
}

.brand-copy {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
}

.brand-name {
  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;
  flex: 1 1 auto;
  align-items: center;
  gap: 25px;
}

.desktop-nav a {
  color: var(--color-muted);
  font-size: 14px;
  font-weight: 550;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

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

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

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

.language-switcher {
  position: relative;
}

.language-button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 6px;
  border: 0;
  background: transparent;
  color: var(--color-muted);
  font-size: 13px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 55;
  display: none;
  width: 168px;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  box-shadow: var(--shadow-card);
}

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

.language-menu a {
  display: flex;
  min-height: 42px;
  align-items: center;
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  font-size: 13px;
}

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

.login-button {
  min-height: 38px;
  border-color: var(--color-accent);
  border-radius: var(--radius-sm);
  padding: 8px 18px;
  color: var(--color-accent-dark);
  font-size: 14px;
}

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

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

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  width: 18px;
  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: 100%;
  right: 0;
  left: 0;
  z-index: 54;
  display: none;
  max-height: calc(100dvh - var(--header-height));
  overflow-y: auto;
  overscroll-behavior: contain;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
}

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

.mobile-nav-inner {
  padding-block: 8px 16px;
}

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 46px;
  align-items: center;
  border-bottom: 1px solid var(--color-border);
  padding: 10px 2px;
  color: var(--color-text);
}

.mobile-language-list {
  padding-top: 10px;
}

.mobile-language-list strong {
  display: block;
  padding: 8px 2px;
  color: var(--color-muted);
  font-size: 12px;
}

.nav-veil {
  position: fixed;
  inset: var(--header-height) 0 0;
  z-index: 40;
  display: none;
  border: 0;
  background: var(--color-overlay);
}

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

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

.footer-main {
  display: grid;
  grid-template-columns: minmax(240px, 1.25fr) repeat(3, minmax(150px, .75fr));
  gap: 42px;
  padding-top: 58px;
  padding-bottom: 44px;
}

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

.footer-column h2 {
  margin-bottom: 14px;
  font-size: 14px;
  letter-spacing: .02em;
}

.footer-links {
  display: grid;
  gap: 9px;
  margin: 0;
  padding: 0;
  list-style: none;
}

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

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

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px 24px;
  padding-top: 20px;
  padding-bottom: 24px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 12px;
}

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

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

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

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

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

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

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

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

.prose table {
  width: 100%;
  border-collapse: collapse;
}

.prose > .data-table {
  display: block;
  min-width: 0;
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

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

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

@media (max-width: 1120px) {
  .desktop-nav {
    gap: 16px;
  }

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

  .brand-local {
    display: none;
  }
}

@media (max-width: 960px) {
  .desktop-nav,
  .language-switcher {
    display: none;
  }

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

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

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

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

@media (max-width: 768px) {
  :root {
    --gutter: 20px;
    --section-space: 72px;
  }

  h1,
  .hero-title {
    font-size: clamp(28px, 9.6vw, 40px);
    letter-spacing: -.015em;
  }

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

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

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

  .absolute-decoration,
  .decorative-label {
    display: none;
  }
}

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

  .header-inner {
    gap: 10px;
  }

  .brand-copy {
    gap: 0;
  }

  .brand-local {
    display: none;
  }

  .login-button {
    min-height: 40px;
    padding-inline: 13px;
  }

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

  .button-row > .button,
  .cta-row > .btn-primary,
  .cta-row > .btn-secondary,
  .cta-row > .btn-ghost {
    flex: 1 1 100%;
  }

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

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

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

@media (max-width: 360px) {
  .brand-name {
    font-size: 17px;
  }

  .brand-logo {
    width: 31px;
    height: 31px;
  }

  .header-tools {
    gap: 6px;
  }
}

@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;
  }
}