:root {
  --color-page: #FFFFFF;
  --color-panel: #F7F8FA;
  --color-panel-strong: #EFF1F5;
  --color-line: #E4E6EC;
  --color-brand: #3B2ED0;
  --color-brand-deep: #2B1FA3;
  --color-ink: #171A24;
  --color-ink-muted: #5C6272;
  --color-positive: #149A57;
  --color-caution: #DE8F0A;
  --color-danger: #D6403A;
  --color-device: #12141F;
  --color-device-panel: #1A1D2C;
  --color-device-raised: #222639;
  --color-device-line: #2A2E44;
  --color-device-ink: #E9EBF4;
  --color-device-muted: #A5AABD;
  --color-white: #FFFFFF;
  --color-shadow-soft: rgba(23, 26, 36, 0.05);
  --color-shadow-mid: rgba(23, 26, 36, 0.14);
  --color-shadow-device: rgba(18, 20, 31, 0.22);
  --color-shadow-brand: rgba(59, 46, 208, 0.28);
  --color-shadow-brand-deep: rgba(43, 31, 163, 0.30);
  --color-overlay: rgba(18, 20, 31, 0.46);
  --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, "Courier New", monospace;
  --radius-small: 8px;
  --radius-medium: 12px;
  --radius-pill: 999px;
  --shadow-card: 0 1px 2px var(--color-shadow-soft), 0 4px 10px var(--color-shadow-soft);
  --shadow-float: 0 1px 2px var(--color-shadow-mid), 0 10px 24px var(--color-shadow-mid), 0 26px 52px var(--color-shadow-soft);
  --shadow-device: 0 2px 4px var(--color-shadow-mid), 0 18px 40px var(--color-shadow-device), 0 44px 88px var(--color-shadow-device);
  --shadow-button: 0 1px 2px var(--color-shadow-brand-deep), 0 6px 16px var(--color-shadow-brand);
  --content-width: 1160px;
  --header-width: 1280px;
  --reading-width: 820px;
  --gutter: clamp(16px, 4vw, 40px);
  --header-height: 70px;
  --section-space: clamp(64px, 9vw, 112px);
  --transition-fast: 160ms ease;
  --transition-reveal: 520ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background: var(--color-page);
}

html.nav-open {
  overflow: hidden;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: clip;
  color: var(--color-ink);
  background: var(--color-page);
  font-family: var(--font-body);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

svg {
  flex-shrink: 0;
}

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

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  border: 0;
}

a {
  color: var(--color-brand);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--color-brand-deep);
}

p,
ul,
ol,
dl,
blockquote,
pre,
table {
  margin-top: 0;
  margin-bottom: 1.25rem;
}

ul,
ol {
  padding-left: 1.4rem;
}

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

h1 {
  margin-bottom: 1.25rem;
  font-size: clamp(34px, 4.2vw, 48px);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.14;
}

h2 {
  margin-bottom: 1rem;
  font-size: clamp(28px, 3vw, 38px);
  font-weight: 850;
  letter-spacing: -0.018em;
  line-height: 1.22;
}

h3 {
  margin-bottom: 0.75rem;
  font-size: clamp(20px, 2vw, 26px);
  font-weight: 800;
  line-height: 1.3;
}

h4 {
  margin-bottom: 0.6rem;
  font-size: 1.05rem;
  font-weight: 750;
}

strong {
  color: var(--color-ink);
  font-weight: 750;
}

small {
  font-size: 0.875rem;
}

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

:not(pre) > code {
  padding: 0.12em 0.36em;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  color: var(--color-ink);
  background: var(--color-panel);
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  padding: 18px 20px;
  overflow-x: auto;
  border: 1px solid var(--color-device-line);
  border-radius: var(--radius-medium);
  color: var(--color-device-ink);
  background: var(--color-device);
  font-family: var(--font-mono);
  line-height: 1.65;
  -webkit-overflow-scrolling: touch;
}

pre code {
  color: inherit;
  background: transparent;
  white-space: pre;
}

hr {
  margin: 2.5rem 0;
  border: 0;
  border-top: 1px solid var(--color-line);
}

table {
  width: 100%;
  border-collapse: collapse;
  color: var(--color-ink);
  background: var(--color-page);
}

th,
td {
  padding: 13px 15px;
  border: 1px solid var(--color-line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--color-ink);
  background: var(--color-panel-strong);
  font-weight: 750;
}

.wrap {
  width: 100%;
  max-width: calc(var(--content-width) + var(--gutter) * 2);
  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);
}

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

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

.section-bordered {
  border-top: 1px solid var(--color-line);
}

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

.section-head {
  max-width: 720px;
  margin-bottom: clamp(30px, 5vw, 52px);
}

.kicker {
  margin-bottom: 10px;
  color: var(--color-brand);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.lede {
  max-width: 720px;
  color: var(--color-ink-muted);
  font-size: clamp(17px, 1.8vw, 20px);
  line-height: 1.75;
}

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

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

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

.stack {
  display: grid;
  gap: 20px;
}

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

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

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

.panel {
  padding: clamp(18px, 3vw, 26px);
  background: var(--color-panel);
}

.button {
  display: inline-flex;
  min-height: 46px;
  max-width: 100%;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 11px 22px;
  border: 1px solid transparent;
  border-radius: var(--radius-small);
  font-weight: 750;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast);
}

.button svg {
  width: 18px;
  height: 18px;
}

.button-primary {
  border-color: var(--color-brand);
  color: var(--color-white);
  background: var(--color-brand);
  box-shadow: var(--shadow-button);
}

.button-primary:hover {
  border-color: var(--color-brand-deep);
  color: var(--color-white);
  background: var(--color-brand-deep);
}

.button-secondary {
  border-color: var(--color-line);
  color: var(--color-ink);
  background: var(--color-page);
}

.button-secondary:hover {
  border-color: var(--color-ink-muted);
  color: var(--color-ink);
  background: var(--color-panel);
}

.button:focus-visible,
.site-nav a:focus-visible,
.header-tool:focus-visible,
.mobile-nav a:focus-visible {
  outline: 3px solid var(--color-brand);
  outline-offset: 3px;
}

.button[aria-disabled="true"],
.button:disabled {
  opacity: 0.56;
  cursor: not-allowed;
  box-shadow: none;
}

.badge,
.fact-chip {
  display: inline-flex;
  max-width: 100%;
  align-items: center;
  gap: 7px;
  padding: 6px 11px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  color: var(--color-ink-muted);
  background: var(--color-page);
  font-size: 0.82rem;
  font-weight: 700;
  line-height: 1.25;
  overflow-wrap: anywhere;
}

.status-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-positive);
}

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity var(--transition-reveal), transform var(--transition-reveal);
}

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

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

.header-row {
  display: flex;
  min-height: var(--header-height);
  align-items: center;
  gap: 24px;
}

.site-brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  color: var(--color-ink);
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 850;
  letter-spacing: -0.01em;
  text-decoration: none;
}

.site-brand:hover {
  color: var(--color-ink);
}

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

.site-nav {
  display: flex;
  margin-left: auto;
  align-items: center;
  gap: 4px;
}

.site-nav a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 7px;
  padding: 8px 12px;
  border-radius: var(--radius-small);
  color: var(--color-ink-muted);
  font-size: 0.9rem;
  font-weight: 700;
  text-decoration: none;
}

.site-nav a svg {
  width: 16px;
  height: 16px;
}

.site-nav a:hover {
  color: var(--color-ink);
  background: var(--color-panel);
}

.site-nav a.is-active {
  color: var(--color-brand);
}

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

.header-tool {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 7px 12px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  color: var(--color-ink-muted);
  background: var(--color-page);
  font-weight: 700;
  cursor: pointer;
}

.header-tool svg {
  width: 17px;
  height: 17px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 4;
  width: 180px;
  padding: 7px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-medium);
  color: var(--color-ink);
  background: var(--color-page);
  box-shadow: var(--shadow-float);
}

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

.language-menu a {
  display: flex;
  width: 100%;
  min-height: 42px;
  align-items: center;
  padding: 8px 10px;
  border-radius: var(--radius-small);
  color: var(--color-ink);
  text-decoration: none;
}

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

.lang-short {
  display: none;
}

.menu-toggle {
  display: none;
  min-width: 44px;
  min-height: 44px;
  padding: 9px;
}

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

.mobile-nav {
  display: none;
}

.nav-veil {
  display: none;
}

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

.footer-grid {
  display: grid;
  grid-template-columns: minmax(240px, 1.4fr) repeat(3, minmax(150px, 1fr));
  gap: 40px;
  padding-top: 58px;
  padding-bottom: 44px;
}

.footer-brand-copy {
  max-width: 360px;
  margin-top: 15px;
  font-size: 0.92rem;
}

.footer-title {
  margin-bottom: 14px;
  color: var(--color-ink);
  font-size: 0.9rem;
  font-weight: 800;
}

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

.footer-links a {
  color: var(--color-ink-muted);
  font-size: 0.9rem;
  text-decoration: none;
}

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

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 22px;
  align-items: center;
  justify-content: space-between;
  padding-top: 20px;
  padding-bottom: 24px;
  border-top: 1px solid var(--color-line);
  font-size: 0.84rem;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.footer-legal a {
  color: var(--color-ink-muted);
  text-decoration: none;
}

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

.prose h2 {
  margin-top: 3rem;
}

.prose h3 {
  margin-top: 2rem;
}

.prose a {
  overflow-wrap: anywhere;
}

.prose img {
  height: auto;
  margin: 2rem auto;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-medium);
}

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

.table-scroll {
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.tilt-card {
  transform: rotate(-2deg);
  transform-origin: center;
}

.decorated-section {
  position: relative;
  overflow-x: clip;
}

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

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

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

  .mobile-nav {
    position: absolute;
    top: 100%;
    right: var(--gutter);
    left: var(--gutter);
    z-index: 3;
    max-height: calc(100dvh - var(--header-height) - 16px);
    padding: 10px;
    overflow-y: auto;
    overscroll-behavior: contain;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-medium);
    color: var(--color-ink);
    background: var(--color-page);
    box-shadow: var(--shadow-float);
  }

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

  .mobile-nav a {
    display: flex;
    width: 100%;
    min-height: 46px;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: var(--radius-small);
    color: var(--color-ink);
    font-weight: 700;
    text-decoration: none;
  }

  .mobile-nav a svg {
    width: 18px;
    height: 18px;
  }

  .mobile-nav a:hover,
  .mobile-nav a.is-active,
  .mobile-nav a[aria-current="true"] {
    color: var(--color-brand);
    background: var(--color-panel);
  }

  .mobile-nav-separator {
    height: 1px;
    margin: 9px 4px;
    background: var(--color-line);
  }

  .nav-veil {
    position: fixed;
    inset: var(--header-height) 0 0;
    z-index: -1;
    background: var(--color-overlay);
  }

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

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

@media (max-width: 768px) {
  h1 {
    font-size: clamp(24px, 8vw, 30px);
    line-height: 1.18;
  }

  h2 {
    font-size: clamp(24px, 7vw, 30px);
  }

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

  .lang-full {
    display: none;
  }

  .lang-short {
    display: inline;
  }
}

@media (max-width: 640px) {
  :root {
    --header-height: 64px;
  }

  .header-row {
    gap: 10px;
  }

  .site-brand {
    font-size: 1rem;
  }

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

  .desktop-language {
    padding-inline: 10px;
  }

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

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

  .tilt-card,
  [class*="tilt"] {
    transform: none;
  }

  .cluster {
    flex-direction: row;
    flex-wrap: wrap;
  }

  th,
  td {
    padding: 11px 12px;
  }
}

@media (max-width: 390px) {
  .site-brand-name {
    display: none;
  }

  .header-tool {
    padding-inline: 9px;
  }
}

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

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

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