/* NKS-471 / ALAN-82 — approved Notes support-page style; system fonts only. */
:root {
  --canvas: #EEF0F4;
  --surface: #FBFCFE;
  --card: #FFFFFF;
  --border: #DCE0E8;
  --ink: #1E2230;
  --ink-2: #5A6072;
  --ink-3: #9AA0AE;
  --accent: #4257B5;
  --accent-ink: #35468F;
  --accent-soft: #E9ECF7;
  --serif: "Iowan Old Style", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", sans-serif;
  --radius: 10px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
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: 760px; margin: 0 auto; padding: 0 24px; }

/* nav（与首页同构） */
.nav { display: flex; align-items: center; justify-content: space-between; padding: 22px 0; }
.logo {
  font-family: var(--serif); font-weight: 600; font-size: 22px;
  letter-spacing: -0.01em; color: var(--ink); text-decoration: none;
  display: inline-flex; align-items: center; gap: 9px;
}
.logo .dot { color: var(--accent); }
.logo svg { display: block; }
.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);
  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); }
.nav-right { display: flex; align-items: center; gap: 18px; }
.nav-link { font-size: 14px; font-weight: 550; color: var(--ink-2); text-decoration: none; }
.nav-link:hover { color: var(--accent-ink); }

/* 正文 */
main { padding: 32px 0 72px; }
h1 {
  font-family: var(--serif); font-weight: 500; font-size: clamp(30px, 5vw, 40px);
  line-height: 1.15; letter-spacing: -0.01em;
}
.meta { margin-top: 12px; font-size: 14px; color: var(--ink-3); }
h2 {
  font-family: var(--serif); font-weight: 550; font-size: 22px;
  line-height: 1.3; margin-top: 44px;
}
main p, main ul, main ol { margin-top: 14px; color: var(--ink-2); }
main strong { color: var(--ink); font-weight: 600; }
main ul, main ol { padding-left: 24px; }
main li + li { margin-top: 6px; }
main a { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }
main a:hover { color: var(--accent); }

/* footer（与首页同构） */
footer { padding: 48px 0 64px; }
.foot-row { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
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); }
/* Notes page navigation and contents. */
.subnav{display:flex;gap:28px;border-bottom:1px solid var(--border)}
.subnav a{padding:14px 0;color:var(--ink-2);text-decoration:none;font-size:15px}
.subnav a[aria-current]{color:var(--accent-ink);border-bottom:2px solid var(--accent)}
main.wrap{padding-top:44px;padding-bottom:30px}.eyebrow{font-size:12px;letter-spacing:.14em;margin-bottom:14px!important;color:var(--accent-ink)!important}
.intro{font-size:18px;margin-top:20px}.contents{padding:20px 24px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);margin-top:28px}
.contents p{margin-top:0;font-size:13px;font-weight:600}.contents ol{display:grid;grid-template-columns:1fr 1fr;gap:4px 30px;margin-top:12px}.contents a{font-size:14px}
section{scroll-margin-top:24px}a:focus-visible{outline:2px solid var(--accent);outline-offset:5px}footer{border-top:1px solid var(--border);margin-top:36px!important}
@media(max-width:540px){.wrap{padding-left:22px;padding-right:22px}.contents ol{grid-template-columns:1fr}.logo{font-size:21px}.nav{gap:16px}.subnav{gap:24px}main.wrap{padding-top:30px}.intro{font-size:17px}h2{font-size:21px}}