*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{--accent:#374151;--accent-light:#6b7280;--ink:#111827;--muted:#6b7280;--line:#d1d5db;--bg:#fff;--max:880px;--section-gap:4rem}
html{scroll-behavior:smooth;scroll-padding-top:72px}
body{font-family:"Noto Sans SC",system-ui,sans-serif;background:var(--bg);color:var(--ink);line-height:1.85;font-size:16px;font-weight:400}
img{max-width:100%;height:auto;display:block}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:var(--max);margin:0 auto;padding:0 1.5rem}
.site-header{border-bottom:1px solid var(--line);background:var(--bg);position:sticky;top:0;z-index:100}
.header-row{display:flex;align-items:center;justify-content:space-between;min-height:58px;gap:1rem}
.brand{display:flex;align-items:center;gap:.6rem;color:var(--ink);font-size:.95rem;text-decoration:none;font-weight:500;letter-spacing:.01em}
.nav-toggle{display:none;flex-direction:column;gap:5px;background:none;border:1px solid var(--line);cursor:pointer;padding:8px;border-radius:2px}
.nav-toggle span{display:block;width:20px;height:1px;background:var(--accent)}
.site-nav ul{display:flex;gap:1.5rem;list-style:none;flex-wrap:wrap}
.site-nav a{color:var(--muted);font-size:.88rem;text-decoration:none;font-weight:400;letter-spacing:.02em}
.site-nav a.active,.site-nav a:hover{color:var(--accent)}
.ads-top-bar{border-bottom:1px solid var(--line);padding:.75rem 0;background:var(--bg)}
.applist-title{font-size:.78rem;color:var(--muted);margin-bottom:.4rem;text-align:center;letter-spacing:.05em}
#ads{display:flex;justify-content:center;flex-wrap:wrap;gap:.5rem}
.hero-line{padding:var(--section-gap) 0;border-bottom:1px solid var(--line)}
.hero-inner{max-width:720px}
.hero-line h1{font-size:clamp(1.3rem,3vw,1.75rem);font-weight:500;line-height:1.4;margin-bottom:1.5rem;color:var(--accent);letter-spacing:.01em}
.hero-lead{font-size:1rem;line-height:1.9;color:var(--muted);text-align:justify}
.hero-lead strong{color:var(--ink);font-weight:500}
.link-strip{display:flex;flex-wrap:wrap;gap:1rem;padding:2.5rem 0;border-bottom:1px solid var(--line)}
.link-strip a{padding:.45rem 1rem;border:1px solid var(--line);font-size:.85rem;color:var(--accent);background:var(--bg);font-weight:400;letter-spacing:.02em}
.link-strip a:hover{border-color:var(--accent);text-decoration:none}
.line-section{padding:var(--section-gap) 0;border-bottom:1px solid var(--line)}
.line-section:last-of-type{border-bottom:none}
.line-inner{max-width:720px}
.line-title{font-size:1.1rem;font-weight:500;color:var(--accent);margin-bottom:2rem;padding-bottom:.75rem;border-bottom:1px solid var(--line);letter-spacing:.02em}
.line-body p{margin-bottom:1.25rem;text-align:justify;color:#374151;font-size:.98rem;line-height:1.9}
.content-fig img{width:100%;max-width:560px;margin:2rem auto;border:1px solid var(--line)}
.content-fig figcaption{font-size:.75rem;color:var(--muted);margin-top:.75rem;text-align:center;letter-spacing:.03em}
.faq-inner details{border:1px solid var(--line);margin-bottom:1rem;background:var(--bg)}
.faq-inner summary{cursor:pointer;padding:1rem 1.25rem;font-weight:500;list-style:none;color:var(--accent);font-size:.95rem}
.faq-inner summary::-webkit-details-marker{display:none}
.faq-inner details[open] summary{border-bottom:1px solid var(--line)}
.faq-inner details p{padding:1rem 1.25rem;font-size:.92rem;color:var(--muted);line-height:1.85}
.related-read{padding:var(--section-gap) 0;border-top:1px solid var(--line);margin-top:0}
.related-read h2{font-size:.95rem;margin-bottom:1.5rem;color:var(--accent);font-weight:500;letter-spacing:.03em}
.related-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:1rem}
.related-grid a{display:block;padding:.75rem;border:1px solid var(--line);text-align:center;font-size:.85rem;color:var(--ink);text-decoration:none}
.related-grid a:hover{border-color:var(--accent);color:var(--accent)}
.site-footer{border-top:1px solid var(--line);padding:2.5rem 0 3rem;background:var(--bg);margin-top:0}
.footer-links{display:flex;flex-wrap:wrap;gap:1.25rem;margin-bottom:1rem}
.footer-links a{font-size:.82rem;color:var(--muted);text-decoration:none;letter-spacing:.02em}
.site-footer p{font-size:.78rem;color:var(--muted)}
.page-head{padding:var(--section-gap) 0 2rem;border-bottom:1px solid var(--line)}
.page-head h1{font-size:1.4rem;font-weight:500;color:var(--accent);margin-top:.5rem}
.breadcrumb{font-size:.82rem;color:var(--muted)}
.breadcrumb a{color:var(--muted)}
.prose-page{padding:2.5rem 0 var(--section-gap);max-width:720px}
.prose-page h2{font-size:1.05rem;margin:2rem 0 1rem;color:var(--accent);font-weight:500}
.prose-page p{margin-bottom:1.25rem;text-align:justify;color:#374151;line-height:1.9}
.error-page{min-height:55vh;display:flex;align-items:center;justify-content:center;text-align:center;padding:2rem}
.error-page h1{font-size:3rem;color:var(--accent);font-weight:300}
@media(max-width:768px){
  :root{--section-gap:3rem}
  .nav-toggle{display:flex}
  .site-nav{position:absolute;top:58px;left:0;right:0;background:var(--bg);border-bottom:1px solid var(--line);padding:1.25rem;display:none}
  .site-nav.is-open{display:block}
  .site-nav ul{flex-direction:column;gap:1rem}
  .header-row{position:relative;flex-wrap:wrap}
}