:root {
  --bg: #ffffff;
  --surface: #f8f9fa;
  --surface-blue: #e8f0fe;
  --ink: #202124;
  --muted: #5f6368;
  --line: #dadce0;
  --accent: #1a73e8;
  --accent-dark: #1765cc;
  --accent-ink: #174ea6;
  --warn-bg: #fef7e0;
  --warn-line: #f9ab00;
  --shadow-1: 0 1px 2px rgba(60, 64, 67, 0.3), 0 1px 3px 1px rgba(60, 64, 67, 0.15);
  --shadow-2: 0 1px 3px rgba(60, 64, 67, 0.3), 0 4px 8px 3px rgba(60, 64, 67, 0.15);
  --sans: "Roboto", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --header-h: 64px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-dark); text-decoration: underline; }
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.skip {
  position: absolute;
  left: 16px;
  top: 12px;
  transform: translateY(-160%);
  background: var(--accent);
  color: white;
  padding: 8px 16px;
  border-radius: 4px;
  z-index: 20;
}
.skip:focus { transform: none; color: white; }

.wrap {
  width: min(1200px, calc(100% - 48px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  width: min(1200px, calc(100% - 48px));
  margin: 0 auto;
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.logo {
  color: var(--ink);
  font-size: 22px;
  font-weight: 500;
  flex: none;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.logo::before {
  content: "";
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--accent) url("../favicon.svg?v=3") center / cover no-repeat;
}
.logo:hover { color: var(--ink); text-decoration: none; }
.logo-tag {
  padding-left: 10px;
  border-left: 1px solid var(--line);
  font-size: 15px;
  font-weight: 400;
  color: var(--muted);
  white-space: nowrap;
}
.site-nav {
  display: flex;
  align-items: center;
  align-self: stretch;
  gap: 4px;
  flex-wrap: wrap;
  justify-content: flex-end;
}
.site-nav a:not(.btn) {
  display: inline-flex;
  align-items: center;
  align-self: stretch;
  padding: 0 12px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
  box-shadow: inset 0 -3px 0 transparent;
}
.site-nav a:not(.btn):hover { color: var(--ink); text-decoration: none; background: var(--surface); }
.site-nav a[aria-current="page"] {
  color: var(--accent);
  box-shadow: inset 0 -3px 0 var(--accent);
}
.site-nav .btn { margin-left: 12px; }
.nav-toggle {
  display: none;
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--ink);
  border-radius: 20px;
  min-height: 40px;
  padding: 0 16px;
  font: inherit;
  font-size: 14px;
  font-weight: 500;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 24px;
  border-radius: 20px;
  background: var(--accent);
  color: white !important;
  border: 1px solid var(--accent);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
  text-decoration: none !important;
  transition: background 0.15s, box-shadow 0.15s;
}
.btn:hover { background: var(--accent-dark); border-color: var(--accent-dark); box-shadow: var(--shadow-1); }
.btn.light {
  background: var(--bg);
  color: var(--accent) !important;
  border-color: var(--line);
}
.btn.light:hover { background: var(--surface-blue); border-color: var(--line); box-shadow: none; }

.hero {
  position: relative;
  padding: 64px 0 56px;
  isolation: isolate;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0 calc(50% - 50vw);
  z-index: -1;
  background: linear-gradient(180deg, var(--surface-blue) 0%, var(--bg) 100%);
}
.kicker {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 20px;
}
.kicker span {
  padding: 4px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
  white-space: nowrap;
}
h1 {
  margin: 0;
  font-size: clamp(34px, 6vw, 56px);
  font-weight: 400;
  line-height: 1.15;
  letter-spacing: -0.01em;
}
.lede {
  max-width: 720px;
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 18px;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.crumb {
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 14px;
}
.crumb a { color: var(--accent); }

.section { padding: 40px 0 8px; }
.section h2, .contact-band h2 {
  margin: 0 0 12px;
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 400;
  line-height: 1.3;
}
.section > p, .prose p { color: var(--muted); }
.prose { max-width: 800px; margin-left: max(24px, calc((100% - 1200px) / 2)); }
.prose h2 { margin-top: 8px; }
.prose p { margin: 0 0 12px; }

.grid-3, .grid-2 { display: grid; gap: 24px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  display: flex;
  flex-direction: column;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 24px;
  transition: box-shadow 0.2s, border-color 0.2s;
}
.card:hover { border-color: transparent; box-shadow: var(--shadow-2); }
.card h3 {
  margin: 0 0 8px;
  font-size: 20px;
  font-weight: 500;
  line-height: 1.4;
}
.card p { margin: 0; color: var(--muted); }
.card a.more {
  margin-top: auto;
  padding-top: 20px;
  color: var(--accent);
  font-size: 14px;
  font-weight: 500;
}
.card a.more::after { content: " →"; }
.index {
  align-self: flex-start;
  margin-bottom: 16px;
  padding: 2px 10px;
  border-radius: 12px;
  background: var(--surface-blue);
  color: var(--accent-ink);
  font-size: 12px;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}

.section.wrap { overflow-x: auto; }
table {
  width: 100%;
  min-width: 640px;
  border-collapse: separate;
  border-spacing: 0;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  font-size: 15px;
}
th, td {
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
th { background: var(--surface); color: var(--ink); font-weight: 500; }
td { color: var(--muted); }
tr:last-child td { border-bottom: 0; }
td a { font-weight: 500; }

.faq {
  border-top: 1px solid var(--line);
}
.faq details { border-bottom: 1px solid var(--line); }
.faq summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 18px 4px;
  cursor: pointer;
  font-weight: 500;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "";
  flex: none;
  width: 8px;
  height: 8px;
  margin-right: 6px;
  border-right: 2px solid var(--muted);
  border-bottom: 2px solid var(--muted);
  transform: rotate(45deg) translateY(-3px);
  transition: transform 0.2s;
}
.faq details[open] summary::after { transform: rotate(-135deg) translateY(-3px); }
.faq summary:hover { color: var(--accent); }
.faq p { margin: 0; padding: 0 4px 18px; color: var(--muted); }

.callout {
  margin-top: 16px;
  padding: 16px 20px;
  border-left: 4px solid var(--warn-line);
  border-radius: 4px;
  background: var(--warn-bg);
  color: var(--ink) !important;
}

#contact { scroll-margin-top: calc(var(--header-h) + 16px); }
.contact-band {
  margin: 56px 0 24px;
  padding: 40px;
  border-radius: 16px;
  background: var(--surface-blue);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
}
.contact-band h2 { color: var(--ink); }
.contact-band p { margin: 6px 0 0; color: var(--muted); max-width: 680px; }
.contact-band a:not(.btn) { color: var(--accent-ink); font-weight: 500; }
.contact-band .btn { flex: none; }

.site-footer {
  margin-top: 40px;
  padding: 40px 0 24px;
  background: var(--surface);
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: 32px;
}
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--ink); }
.site-footer p a { color: var(--accent); }
.site-footer h2 {
  margin: 0 0 12px;
  color: var(--ink);
  font-size: 15px;
  font-weight: 500;
}
.site-footer p { margin: 0; }
.site-footer ul { margin: 0; padding: 0; list-style: none; }
.site-footer li { margin: 8px 0; }
.fine {
  margin: 28px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
}

@media (max-width: 1080px) {
  .logo-tag { display: none; }
}

@media (max-width: 900px) {
  .grid-3, .grid-2, .footer-grid { grid-template-columns: 1fr; }
  .nav-toggle { display: inline-flex; align-items: center; }
  .header-inner { position: relative; }
  .site-nav {
    display: none;
    position: absolute;
    left: -24px;
    right: -24px;
    top: var(--header-h);
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    padding: 8px 0 16px;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }
  .site-nav[data-open="true"] { display: flex; z-index: 11; }
  .site-nav[data-open="true"]::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    height: 100vh;
    background: rgba(32, 33, 36, 0.32);
  }
  .site-nav a:not(.btn) { padding: 12px 24px; box-shadow: none; }
  .site-nav a[aria-current="page"] {
    box-shadow: inset 4px 0 0 var(--accent);
    background: var(--surface-blue);
  }
  .site-nav .btn { margin: 12px 24px 0; }
  .contact-band { flex-direction: column; align-items: flex-start; padding: 28px; }
  .hero { padding: 40px 0 36px; }
  .prose { margin-left: auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .card, .btn, .faq summary::after { transition: none; }
}