:root {
  color-scheme: light;
  --background: #ffffff;
  --surface: #ffffff;
  --ink: #151e2d;
  --muted: #3d4b60;
  --accent: #154fc9;
  --accent-hover: #0d3593;
  --accent-soft: #e8efff;
  --border: #bbc5d3;
  font-family: "Segoe UI", "Microsoft YaHei UI", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink);
  background: var(--background);
  font-synthesis: none;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
  scrollbar-color: #738097 var(--background);
}
* { box-sizing: border-box; }
body { margin: 0; }
::selection { background: #cbdcff; color: #122d60; }
button, a, summary { -webkit-tap-highlight-color: transparent; }
button { font: inherit; cursor: pointer; }
a { color: var(--accent); text-underline-offset: 4px; }
a:hover { color: var(--accent-hover); }
a:focus-visible, button:focus-visible, summary:focus-visible, [tabindex]:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; border-radius: 4px; }
h1, h2, h3, p { margin: 0; }
h1, h2, h3 { text-wrap: balance; }
p { text-wrap: pretty; }
svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; flex: none; }
.page-width, .header-inner { width: min(1040px, calc(100% - 64px)); margin-inline: auto; }
.skip-link { position: fixed; top: 12px; left: 12px; z-index: 10; padding: 8px 16px; background: var(--surface); transform: translateY(-200%); }
.skip-link:focus { transform: none; }
.site-header { position: sticky; top: 0; z-index: 5; background: var(--surface); border-bottom: 1px solid var(--border); }
.header-inner { display: flex; align-items: center; justify-content: space-between; min-height: 72px; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 12px; text-decoration: none; color: var(--ink); flex: none; }
.brand strong { font-size: 22px; letter-spacing: -.02em; }
.brand img { display: block; }
.site-header nav { display: flex; align-items: center; gap: 28px; }
.site-header nav a { display: inline-flex; align-items: center; min-height: 44px; font-size: 15px; font-weight: 600; text-decoration: none; color: var(--ink); }
.site-header nav a:hover, .site-header nav .nav-download { color: var(--accent); }
.intro { padding-block: 64px; display: grid; grid-template-columns: 1.35fr 1fr; gap: 80px; align-items: center; }
h1 { font-size: clamp(36px, 4.1vw, 50px); line-height: 1.35; letter-spacing: -.025em; font-weight: 700; }
.lead { margin-top: 20px; max-width: 28em; color: var(--muted); font-size: 18px; line-height: 1.8; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 10px; padding: 12px 20px; min-height: 48px; border-radius: 8px; border: 1px solid transparent; font-size: 16px; font-weight: 600; text-decoration: none; transition: background-color 160ms, border-color 160ms; }
.button.primary { background: var(--accent); color: white; margin-top: 28px; }
.button.primary:hover { background: var(--accent-hover); }
.button.secondary { background: var(--surface); color: var(--ink); border-color: var(--border); }
.button.secondary:hover { background: var(--accent-soft); border-color: var(--accent); }
.download-meta { margin-top: 12px; font-size: 14px; color: var(--muted); font-variant-numeric: tabular-nums; }
.download-meta span { margin-inline: 5px; }
.start-guide h2 { font-size: 22px; line-height: 1.5; }
.start-guide ol { padding: 0; margin: 24px 0 0; list-style: none; }
.start-guide li { display: flex; gap: 16px; margin-top: 20px; }
.start-guide li:first-child { margin-top: 0; }
.step-index { flex: none; display: flex; justify-content: center; align-items: center; width: 28px; height: 28px; color: var(--accent); font-size: 16px; font-weight: 600; font-variant-numeric: tabular-nums; }
.start-guide h3 { font-size: 16px; }
.start-guide li p { margin-top: 3px; color: var(--muted); font-size: 15px; }
.workflow { border-top: 1px solid var(--border); padding-top: 40px; }
h2 { font-size: 26px; line-height: 1.5; letter-spacing: -.018em; }
.flow-tabs { display: flex; gap: 36px; margin-top: 16px; border-bottom: 1px solid var(--border); }
.flow-tabs button { position: relative; display: inline-flex; align-items: center; gap: 9px; min-height: 56px; padding: 12px 1px; color: var(--muted); background: transparent; border: 0; font-size: 16px; font-weight: 600; }
.flow-tabs button > span { font-size: 15px; font-variant-numeric: tabular-nums; }
.flow-tabs button::after { content: ""; position: absolute; bottom: -1px; left: 0; right: 0; height: 3px; border-radius: 2px; background: transparent; }
.flow-tabs button[aria-selected="true"], .flow-tabs button:hover { color: var(--accent); }
.flow-tabs button[aria-selected="true"]::after { background: var(--accent); }
.flow-tabs button:focus-visible { outline-offset: -5px; }
.flow-panel { display: grid; grid-template-columns: 1.3fr 1fr; gap: 20px 64px; padding-block: 28px; min-height: 210px; }
.flow-panel[hidden] { display: none; }
.flow-panel h3 { font-size: 20px; line-height: 1.6; margin-bottom: 12px; }
.flow-panel p { color: var(--muted); max-width: 31em; }
.flow-panel dl { margin: 0; display: flex; flex-direction: column; gap: 14px; font-size: 15px; }
.flow-panel dt { font-weight: 600; color: var(--ink); }
.flow-panel dd { margin: 3px 0 0; color: var(--muted); }
.flow-panel .automation-note { grid-column: 1 / -1; max-width: none; padding-top: 12px; border-top: 1px solid var(--border); color: var(--ink); font-size: 14px; }
.no-script-note { padding-bottom: 24px; color: var(--muted); }
.questions { padding-top: 24px; }
.faq-list { border-top: 1px solid var(--border); margin-top: 20px; }
summary { cursor: pointer; }
.faq-list details { border-bottom: 1px solid var(--border); }
.faq-list summary { position: relative; padding: 18px 36px 18px 0; font-size: 16px; font-weight: 600; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: ""; position: absolute; right: 8px; top: 24px; width: 8px; height: 8px; border-right: 1.5px solid var(--ink); border-bottom: 1.5px solid var(--ink); transform: rotate(45deg); transition: transform 160ms; }
.faq-list details[open] summary::after { transform: rotate(225deg); }
.faq-list details p { max-width: 72ch; color: var(--muted); margin: 0 0 16px; padding-right: 20px; }
.faq-list details p:last-child { margin-bottom: 20px; }
.checksum { margin-block: 28px 40px; font-size: 14px; color: var(--muted); }
.checksum summary { width: fit-content; min-height: 44px; padding-block: 10px; }
.checksum p { margin: 12px 0 8px; }
.checksum code { display: block; font: 14px/1.8 Consolas, monospace; overflow-wrap: anywhere; color: var(--ink); }
.checksum-actions { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; margin-top: 12px; }
.checksum-actions .button { min-height: 44px; padding: 8px 12px; font-size: 14px; }
#copy-status { color: var(--ink); }
.site-footer { display: flex; align-items: center; justify-content: space-between; gap: 20px; border-top: 1px solid var(--border); padding-block: 20px 28px; color: var(--muted); font-size: 14px; }
.site-footer > div { display: flex; gap: 24px; }
.site-footer a { color: var(--muted); padding-block: 10px; }
.panel-enter { animation: panel-reveal 180ms cubic-bezier(.16,1,.3,1); }
@keyframes panel-reveal { from { clip-path: inset(0 1% 0 0); } to { clip-path: inset(0); } }
@media (max-width: 960px) {
  .intro { gap: 40px; }
  .flow-panel { gap: 20px 40px; }
}
@media (max-width: 720px) {
  :root { scroll-padding-top: 78px; }
  .page-width, .header-inner { width: calc(100% - 40px); }
  .header-inner { min-height: 64px; gap: 12px; }
  .brand { gap: 8px; }
  .brand strong { font-size: 19px; }
  .brand img { width: 30px; height: 30px; }
  .site-header nav { gap: 16px; }
  .site-header nav a { font-size: 14px; }
  .site-header nav a[href="#questions"] { display: none; }
  .intro { grid-template-columns: 1fr; gap: 32px; padding-block: 40px; }
  h1 { font-size: clamp(34px, 8.7vw, 46px); }
  .lead { font-size: 16px; margin-top: 16px; }
  .button.primary { margin-top: 24px; }
  .start-guide { padding-top: 24px; border-top: 1px solid var(--border); }
  .start-guide ol { margin-top: 20px; }
  h2 { font-size: 24px; }
  .workflow { padding-top: 32px; }
  .flow-tabs { gap: 24px; }
  .flow-tabs button { font-size: 15px; gap: 6px; }
  .flow-tabs button > span { font-size: 14px; }
  .flow-panel { grid-template-columns: 1fr; padding-block: 24px; gap: 20px; }
  .flow-panel h3 { font-size: 19px; }
  .flow-panel dl { gap: 12px; }
  .questions { padding-top: 12px; }
  .faq-list summary { padding-block: 17px; }
  .site-footer { align-items: start; flex-direction: column; gap: 8px; }
}
@media (prefers-reduced-motion: reduce) {
  :root { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}