/* NKS-308 — Alayo 帮助中心共享样式。
   Token 与 landing（../Alayo Landing Page.html）、use-cases（../use-cases/use-cases.css）同源：
   Noether Indigo #4257B5 / Ink #1E2230 / Newsreader 衬线。
   不引入框架；改 token 请三处保持一致。 */
:root {
  --canvas: #EEF0F4;
  --surface: #FBFCFE;
  --card: #FFFFFF;
  --border: #DCE0E8;
  --ink: #1E2230;
  --ink-2: #5A6072;
  /* ink-3 与 landing 分叉：帮助页小字（面包屑/文章日期/页脚）直接落在 --canvas 上，
     landing 的 #9AA0AE 仅 2.3:1 违反 WCAG AA；#676B76 在 #EEF0F4 上 4.67:1（codex R3） */
  --ink-3: #676B76;
  --accent: #4257B5;
  --accent-ink: #35468F;
  --accent-soft: #E9ECF7;
  --serif: "Newsreader", "Iowan Old Style", Georgia, "Songti SC", "STSong", serif;
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Segoe UI", sans-serif;
  --radius: 10px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--canvas);
  color: var(--ink);
  line-height: 1.7;
  font-size: 16.5px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
::selection { background: var(--accent-soft); }

.wrap { max-width: 860px; margin: 0 auto; padding: 0 24px; }

/* ---------- header ---------- */
.nav {
  display: flex; align-items: center; justify-content: space-between;
  padding: 22px 0; gap: 16px;
}
.logo {
  font-family: var(--serif); font-weight: 600; font-size: 21px;
  letter-spacing: -0.01em; color: var(--ink); text-decoration: none;
  display: inline-flex; align-items: center; gap: 9px; flex: none;
}
.logo .dot { color: var(--accent); }
.logo svg { display: block; }
.logo .crumb {
  font-family: var(--sans); font-size: 14px; font-weight: 500; color: var(--ink-3);
  margin-left: 2px;
}
.lang-switch {
  font-size: 13.5px; font-weight: 590; color: var(--accent-ink);
  text-decoration: none; padding: 7px 14px; border: 1px solid var(--border);
  border-radius: 99px; background: var(--card); flex: none;
  transition: border-color .15s ease, box-shadow .15s ease;
}
.lang-switch:hover { border-color: var(--accent); box-shadow: 0 1px 6px rgba(66,87,181,.12); }

/* ---------- help index ---------- */
.help-hero { padding: 44px 0 12px; }
.help-hero h1 {
  font-family: var(--serif); font-weight: 500; font-size: clamp(32px, 5vw, 44px);
  line-height: 1.15; letter-spacing: -0.012em; text-wrap: balance;
}
.help-hero .subhead { margin-top: 14px; font-size: 17.5px; color: var(--ink-2); max-width: 620px; text-wrap: pretty; }

.article-list { display: grid; gap: 14px; margin: 36px 0 0; }
.article-card {
  display: block; background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 22px 24px; text-decoration: none; color: inherit;
  transition: border-color .15s ease, box-shadow .15s ease, transform .12s ease;
}
.article-card:hover {
  border-color: var(--accent); transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(66,87,181,.10);
}
.article-card h2 {
  font-family: var(--serif); font-weight: 550; font-size: 21px;
  letter-spacing: -0.008em; margin-bottom: 6px;
}
.article-card h2 .arrow { color: var(--accent); font-family: var(--sans); font-size: 17px; }
.article-card p { font-size: 15px; color: var(--ink-2); text-wrap: pretty; }
.section-label {
  font-size: 12.5px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase;
  color: var(--ink-3); margin: 40px 0 0;
}
.section-label + .article-list { margin-top: 14px; }
.coming { opacity: .62; pointer-events: none; }
.coming h2 .arrow { display: none; }

/* ---------- article page ---------- */
.article { padding: 40px 0 8px; }
.article h1 {
  font-family: var(--serif); font-weight: 500; font-size: clamp(30px, 4.6vw, 40px);
  line-height: 1.18; letter-spacing: -0.012em; text-wrap: balance;
}
.article .article-meta { margin-top: 10px; font-size: 13.5px; color: var(--ink-3); }
.article .lede { margin-top: 18px; font-size: 18px; color: var(--ink-2); text-wrap: pretty; }
.prose { margin-top: 12px; max-width: 720px; }
.prose h2 {
  font-family: var(--serif); font-weight: 550; font-size: 26px; line-height: 1.25;
  letter-spacing: -0.008em; margin: 44px 0 12px;
}
.prose h3 { font-size: 17.5px; font-weight: 650; margin: 30px 0 8px; letter-spacing: -0.005em; }
.prose p { margin: 12px 0; font-size: 16.5px; color: var(--ink); text-wrap: pretty; }
.prose p.note { font-size: 15px; color: var(--ink-2); }
.prose ul, .prose ol { margin: 12px 0 12px 22px; }
.prose li { margin: 6px 0; }
.prose li::marker { color: var(--accent); }
.prose strong { font-weight: 650; }
.prose em { font-style: italic; }
.prose a { color: var(--accent-ink); text-decoration: underline; text-decoration-color: rgba(66,87,181,.35); text-underline-offset: 3px; }
.prose a:hover { text-decoration-color: var(--accent); }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 36px 0; }
.prose blockquote {
  margin: 16px 0; padding: 14px 20px; background: var(--surface);
  border-left: 3px solid var(--accent); border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--ink-2); font-size: 15.5px;
}
kbd {
  display: inline-block; font-family: var(--sans); font-size: .82em; font-weight: 600;
  color: var(--ink-2); background: var(--surface); border: 1px solid var(--border);
  border-bottom-width: 2px; border-radius: 6px; padding: 1px 7px; margin: 0 1px;
  white-space: nowrap;
}
.prose img, .prose video {
  max-width: 100%; border: 1px solid var(--border); border-radius: 12px;
  box-shadow: 0 12px 32px -16px rgba(30,34,48,.18); margin: 8px 0;
}
.prose .callout {
  margin: 18px 0; padding: 16px 20px; background: var(--accent-soft);
  border-radius: var(--radius); font-size: 15.5px; color: var(--accent-ink);
}

/* FAQ 列表（与 landing faq-list 同形） */
.faq-list { margin-top: 28px; border-top: 1px solid var(--border); }
.faq-item { border-bottom: 1px solid var(--border); padding: 22px 0; }
.faq-item h3 { font-size: 17px; font-weight: 650; margin-bottom: 8px; letter-spacing: -0.005em; }
.faq-item p { font-size: 15.5px; color: var(--ink-2); text-wrap: pretty; margin: 8px 0 0; }

/* 文章尾导航 */
.article-footer-nav {
  margin-top: 52px; padding-top: 20px; border-top: 1px solid var(--border);
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  font-size: 14.5px;
}
.article-footer-nav a { color: var(--accent-ink); text-decoration: none; font-weight: 550; }
.article-footer-nav a:hover { text-decoration: underline; }

/* ---------- footer ---------- */
footer { padding: 56px 0 64px; }
.foot-row {
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  border-top: 1px solid var(--border); padding-top: 28px;
}
footer p { font-size: 13.5px; color: var(--ink-3); }
footer a { color: var(--ink-2); text-decoration: none; }
footer a:hover { color: var(--accent-ink); }

@media (max-width: 640px) {
  .help-hero { padding: 28px 0 8px; }
  .article { padding: 28px 0 8px; }
  .article-card { padding: 18px 20px; }
  .logo .crumb { display: none; }
}