:root {
  --color-bg: #FFFFFF;
  --color-panel: #F5F8FC;
  --color-panel-strong: #EDF3FB;
  --color-border: #E3E8EF;
  --color-accent: #2B6BE4;
  --color-accent-dark: #1E4FB8;
  --color-text: #10203A;
  --color-text-muted: #5B6B82;
  --color-success: #12915F;
  --color-warning: #C77E14;
  --color-error: #D3382C;
  --color-field-pink: #F6DCEA;
  --color-field-blue: #D8E5FA;
  --color-field-orange: #FAE4D2;
  --color-field-lilac: #E6E0F6;
  --color-overlay: rgba(16, 32, 58, 0.42);
  --color-shadow-soft: rgba(16, 32, 58, 0.06);
  --color-shadow-card: rgba(16, 32, 58, 0.10);
  --color-shadow-accent: rgba(43, 107, 228, 0.16);
  --color-white-shadow: rgba(255, 255, 255, 0.86);

  --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-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 10px;
  --radius-pill: 999px;

  --shadow-soft: 0 1px 2px var(--color-shadow-soft), 0 4px 14px var(--color-shadow-soft);
  --shadow-card: 0 1px 2px var(--color-shadow-soft), 0 14px 34px var(--color-shadow-card), 0 36px 70px var(--color-shadow-accent);
  --shadow-button: 0 1px 2px rgba(30, 79, 184, 0.28), 0 6px 16px rgba(43, 107, 228, 0.24);
  --shadow-pill: 0 1px 2px var(--color-shadow-soft), 0 3px 10px var(--color-shadow-soft);

  --content-width: 1180px;
  --reading-width: 820px;
  --header-width: 1280px;
  --gutter: clamp(16px, 4vw, 30px);
  --header-height: 64px;
  --section-space: clamp(64px, 9vw, 112px);
  --transition-fast: 160ms ease;
  --transition-base: 240ms ease;
  --stripe-pattern: repeating-linear-gradient(-45deg, var(--color-border) 0, var(--color-border) 1px, transparent 1px, transparent 7px);
  --hero-field: radial-gradient(46% 60% at 16% 78%, var(--color-field-pink) 0%, transparent 100%), radial-gradient(42% 58% at 46% 18%, var(--color-field-blue) 0%, transparent 100%), radial-gradient(38% 52% at 86% 12%, var(--color-field-orange) 0%, transparent 100%), radial-gradient(40% 55% at 74% 92%, var(--color-field-lilac) 0%, transparent 100%), var(--color-panel);
}

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

html {
  min-width: 320px;
  scroll-behavior: smooth;
  background: var(--color-bg);
}

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: 15px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

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

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

svg {
  flex-shrink: 0;
}

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

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

button {
  cursor: pointer;
}

ul,
ol {
  margin: 0;
}

ul[role="list"],
ol[role="list"],
.clean-list {
  padding: 0;
  list-style: none;
}

p,
h1,
h2,
h3,
h4,
figure,
blockquote,
pre {
  margin-top: 0;
}

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

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

h1,
.hero-title {
  margin-bottom: 20px;
  font-size: clamp(34px, 4vw, 48px);
  font-weight: 800;
  letter-spacing: -0.015em;
  line-height: 1.16;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(27px, 3vw, 38px);
  font-weight: 760;
  letter-spacing: -0.012em;
  line-height: 1.24;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(20px, 2vw, 25px);
  font-weight: 720;
  line-height: 1.34;
}

h4 {
  margin-bottom: 8px;
  font-size: 17px;
  font-weight: 700;
}

p {
  margin-bottom: 1em;
}

strong {
  font-weight: 700;
}

::selection {
  background: var(--color-field-blue);
  color: var(--color-text);
}

:focus-visible {
  outline: 3px solid var(--color-field-blue);
  outline-offset: 3px;
}

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

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

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

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

.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);
}

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

.section-panel {
  background: var(--color-panel);
  color: var(--color-text);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.stripe-divider {
  height: 26px;
  background: var(--stripe-pattern);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.eyebrow {
  display: inline-flex;
  max-width: 100%;
  align-items: center;
  gap: 8px;
  padding: 5px 13px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.025em;
}

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

.panel,
.card {
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg);
  color: var(--color-text);
  box-shadow: var(--shadow-soft);
}

.panel {
  padding: clamp(20px, 4vw, 34px);
}

.card {
  padding: 22px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.card-grid > * {
  min-width: 0;
}

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

.button {
  display: inline-flex;
  min-height: 46px;
  max-width: 100%;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 22px;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  background: var(--color-accent);
  color: var(--color-bg);
  font-weight: 700;
  line-height: 1.35;
  text-align: center;
  transition: border-color var(--transition-fast), background-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

.button:hover {
  background: var(--color-accent-dark);
  color: var(--color-bg);
  box-shadow: var(--shadow-button);
  transform: translateY(-1px);
}

.button:active {
  transform: translateY(0);
  box-shadow: none;
}

.button-secondary {
  border-color: var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  box-shadow: var(--shadow-pill);
}

.button-secondary:hover {
  border-color: var(--color-accent);
  background: var(--color-bg);
  color: var(--color-accent-dark);
}

.button-quiet {
  border-color: transparent;
  background: var(--color-panel);
  color: var(--color-text);
  box-shadow: none;
}

.button-quiet:hover {
  background: var(--color-panel-strong);
  color: var(--color-accent-dark);
}

.button[disabled],
.button.is-disabled {
  cursor: not-allowed;
  border-color: var(--color-border);
  background: var(--color-panel-strong);
  color: var(--color-text-muted);
  box-shadow: none;
  opacity: 0.72;
  transform: none;
}

code {
  padding: 0.12em 0.34em;
  overflow-wrap: anywhere;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-panel);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 0.9em;
}

pre {
  max-width: 100%;
  padding: 18px;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-text);
  color: var(--color-bg);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  -webkit-overflow-scrolling: touch;
}

pre code {
  padding: 0;
  overflow-wrap: normal;
  border: 0;
  background: transparent;
  color: inherit;
  white-space: pre;
}

.table-scroll {
  display: block;
  width: 100%;
  max-width: 100%;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  -webkit-overflow-scrolling: touch;
}

.data-table {
  width: 100%;
  min-width: 640px;
  border-collapse: collapse;
  background: var(--color-bg);
  color: var(--color-text);
  text-align: left;
}

.data-table th,
.data-table td {
  padding: 13px 15px;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.data-table th {
  background: var(--color-panel);
  color: var(--color-text);
  font-size: 13px;
  font-weight: 750;
}

.data-table tr:last-child td {
  border-bottom: 0;
}

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

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

.prose a {
  color: var(--color-accent-dark);
  font-weight: 600;
  text-decoration: underline;
  text-decoration-color: var(--color-field-blue);
  text-underline-offset: 3px;
}

.prose ul,
.prose ol {
  margin-bottom: 1.2em;
  padding-left: 1.35em;
}

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

.prose h2 {
  margin-top: 2.25em;
}

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

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

.tilt-soft {
  transform: rotate(-0.35deg);
  transform-origin: center;
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 560ms ease, transform 560ms ease;
}

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

/* Header */
.site-header {
  position: relative;
  z-index: 100;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
}

.header-shell {
  display: flex;
  width: 100%;
  max-width: min(100%, calc(var(--header-width) + var(--gutter) * 2));
  height: var(--header-height);
  margin-inline: auto;
  padding-inline: var(--gutter);
  align-items: center;
  gap: 28px;
}

.site-brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  font-size: 16px;
  font-weight: 750;
}

.site-brand img {
  width: 30px;
  height: 30px;
  flex: 0 0 30px;
}

.desktop-nav {
  display: flex;
  height: var(--header-height);
  margin-left: auto;
  align-items: stretch;
  gap: 2px;
}

.desktop-nav a {
  position: relative;
  display: flex;
  min-height: 44px;
  align-items: center;
  padding-inline: 13px;
  color: var(--color-text-muted);
  font-size: 14px;
  font-weight: 550;
}

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

.desktop-nav a.is-active {
  font-weight: 700;
}

.desktop-nav a.is-active::after {
  position: absolute;
  right: 11px;
  bottom: -1px;
  left: 11px;
  height: 2px;
  border-radius: 2px 2px 0 0;
  background: var(--color-accent);
  content: "";
}

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

.language-control {
  position: relative;
}

.language-button {
  display: inline-flex;
  min-height: 38px;
  align-items: center;
  gap: 5px;
  padding: 6px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  color: var(--color-text-muted);
  font-size: 13px;
  white-space: nowrap;
}

.language-button:hover,
.language-button[aria-expanded="true"] {
  border-color: var(--color-accent);
  color: var(--color-text);
}

.language-short {
  display: none;
}

.language-menu {
  position: absolute;
  top: calc(100% + 9px);
  right: 0;
  z-index: 5;
  width: 158px;
  padding: 6px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text);
  box-shadow: var(--shadow-card);
}

.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-sm);
  color: var(--color-text-muted);
  font-size: 13px;
}

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

.menu-toggle {
  display: none;
  min-width: 44px;
  min-height: 44px;
  padding: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  color: var(--color-text);
}

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  display: block;
  width: 20px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: currentColor;
  content: "";
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

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

.menu-toggle-lines::before {
  position: absolute;
  top: -6px;
  left: 0;
}

.menu-toggle-lines::after {
  position: absolute;
  top: 6px;
  left: 0;
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines {
  background: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::before {
  transform: translateY(6px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::after {
  transform: translateY(-6px) rotate(-45deg);
}

.mobile-nav {
  display: none;
}

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

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 48px;
  align-items: center;
  padding: 12px var(--gutter);
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text);
  font-weight: 650;
}

.mobile-nav a.is-active {
  color: var(--color-accent-dark);
}

.mobile-nav-languages {
  padding: 8px 0;
  background: var(--color-panel);
  color: var(--color-text);
}

.mobile-nav-languages strong {
  display: block;
  padding: 8px var(--gutter);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
}

.mobile-nav-languages a {
  background: var(--color-panel);
}

.nav-veil {
  display: none;
}

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

.footer-grid {
  display: grid;
  grid-template-columns: minmax(250px, 1.25fr) repeat(3, minmax(150px, 1fr));
  gap: 42px;
  padding-top: 58px;
  padding-bottom: 46px;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 750;
}

.footer-brand img {
  width: 34px;
  height: 34px;
  flex: 0 0 34px;
}

.footer-intro {
  max-width: 360px;
  margin-top: 16px;
  color: var(--color-text-muted);
  font-size: 14px;
}

.footer-heading {
  margin-bottom: 14px;
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 750;
  letter-spacing: 0.08em;
}

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

.footer-links li + li {
  margin-top: 8px;
}

.footer-links a {
  color: var(--color-text-muted);
  font-size: 14px;
}

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

.footer-bottom {
  display: flex;
  min-height: 62px;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 13px;
}

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

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

@media (max-width: 1040px) {
  .header-shell {
    gap: 16px;
  }

  .desktop-nav a {
    padding-inline: 9px;
  }

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

@media (max-width: 860px) {
  h1,
  .hero-title {
    font-size: clamp(28px, 7vw, 30px);
  }

  .desktop-nav {
    display: none;
  }

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

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

  .mobile-nav {
    position: absolute;
    top: var(--header-height);
    right: 0;
    left: 0;
    z-index: 102;
    display: block;
    max-height: calc(100dvh - var(--header-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    border-top: 1px solid var(--color-border);
    background: var(--color-bg);
    color: var(--color-text);
    box-shadow: var(--shadow-card);
  }

  .nav-veil {
    position: fixed;
    top: var(--header-height);
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 99;
    display: block;
    border: 0;
    background: var(--color-overlay);
  }

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

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

@media (max-width: 640px) {
  :root {
    --gutter: 16px;
    --section-space: 58px;
  }

  body {
    font-size: 14px;
  }

  h1,
  .hero-title {
    font-size: clamp(24px, 8vw, 30px);
    letter-spacing: -0.01em;
  }

  h2 {
    font-size: clamp(23px, 7vw, 29px);
  }

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

  .language-full {
    display: none;
  }

  .language-short {
    display: inline;
  }

  .language-button {
    min-width: 52px;
    justify-content: center;
    padding-inline: 9px;
  }

  .site-brand {
    gap: 8px;
  }

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

  .site-brand span {
    font-size: 15px;
  }

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

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

  .button-row .button {
    flex: 1 1 160px;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .footer-bottom {
    padding-top: 18px;
    padding-bottom: 18px;
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (max-width: 390px) {
  .site-brand span {
    max-width: 102px;
    overflow-wrap: anywhere;
    line-height: 1.2;
  }

  .header-shell {
    gap: 8px;
  }

  .header-tools {
    gap: 5px;
  }
}

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

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

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