:root{
  --ink:#0b2530;
  --ink-2:#173d48;
  --paper:#f4f8f7;
  --white:#ffffff;
  --jade:#2e8b78;
  --mint:#71c8ad;
  --cyan:#5cb8cc;
  --yellow:#f2c45e;
  --coral:#ef806d;
  --muted:#637a82;
  --line:#d7e3e1;
  --font:'Inter','Noto Sans SC','PingFang SC','Microsoft YaHei',sans-serif;
  --serif:'Noto Serif SC','Songti SC',serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--font);-webkit-font-smoothing:antialiased}
a{color:inherit}
img{max-width:100%}
.knowledge-nav{
  height:72px;display:flex;align-items:center;justify-content:space-between;
  padding:0 clamp(20px,5vw,72px);border-bottom:1px solid rgba(11,37,48,.1);
  background:rgba(244,248,247,.94);backdrop-filter:blur(14px);position:sticky;top:0;z-index:20;
}
.knowledge-brand{display:flex;align-items:center;gap:12px;text-decoration:none}
.knowledge-mark{width:38px;height:38px;position:relative;color:var(--jade)}
.knowledge-mark::before,.knowledge-mark::after{content:'';position:absolute;bottom:6px;width:17px;height:25px;border:2px solid currentColor}
.knowledge-mark::before{left:2px;transform:skewY(12deg);border-right-width:1px}
.knowledge-mark::after{right:2px;transform:skewY(-12deg);border-left-width:1px}
.knowledge-mark i{position:absolute;right:0;top:1px;width:8px;height:8px;border-radius:50%;background:var(--yellow);box-shadow:0 0 0 5px rgba(242,196,94,.18)}
.brand-text strong{display:block;font-size:16px;letter-spacing:.08em}
.brand-text span{display:block;margin-top:3px;color:var(--muted);font-size:9px;letter-spacing:.16em;text-transform:uppercase}
.nav-links{display:flex;gap:24px;align-items:center}
.nav-links a{text-decoration:none;color:#45616a;font-size:13px;font-weight:600}
.nav-links a:hover{color:var(--jade)}
.home-link{display:inline-flex;align-items:center;gap:7px}
.home-link::before{content:'←';font-size:17px}
.knowledge-shell{width:min(1180px,calc(100% - 40px));margin:0 auto}
.knowledge-hero{padding:72px 0 56px;display:grid;grid-template-columns:minmax(0,1.05fr) minmax(380px,.95fr);gap:70px;align-items:center}
.hero-copy h1{margin:0;font-size:clamp(48px,6vw,82px);line-height:1.04;letter-spacing:0;font-weight:900}
.hero-copy h1 span{color:var(--jade)}
.hero-copy p{max-width:600px;margin:24px 0 0;color:#506a72;font-size:17px;line-height:1.9}
.hero-principle{margin-top:34px;padding-top:18px;border-top:1px solid var(--line);display:flex;gap:26px;color:#5b7178;font-size:12px}
.hero-principle span{display:flex;align-items:center;gap:8px}
.hero-principle i{width:7px;height:7px;background:var(--yellow);transform:rotate(45deg)}
.hero-visual{position:relative;aspect-ratio:1.22;overflow:hidden;border-radius:6px;background:#dce9ed}
.hero-visual img{display:block;width:100%;height:100%;object-fit:cover}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:30px;padding:28px 0 22px;border-top:1px solid var(--ink)}
.section-head h2{margin:0;font-size:30px}
.section-head p{margin:0;color:var(--muted);font-size:13px}
.featured-article{display:grid;grid-template-columns:1.2fr .8fr;min-height:410px;background:var(--white);border:1px solid var(--line);text-decoration:none;overflow:hidden}
.featured-article img{width:100%;height:100%;object-fit:cover}
.featured-copy{padding:48px;display:flex;flex-direction:column;justify-content:center}
.article-index{font-size:11px;color:var(--jade);font-weight:800;letter-spacing:.16em}
.featured-copy h3{margin:17px 0 18px;font-size:36px;line-height:1.24}
.featured-copy p{margin:0;color:#5d737a;line-height:1.85;font-size:15px}
.article-meta{display:flex;gap:18px;margin-top:30px;color:#71868c;font-size:11px}
.read-more{display:flex;align-items:center;gap:12px;margin-top:34px;color:var(--jade);font-size:13px;font-weight:700}
.read-more::after{content:'→';font-size:19px;transition:transform .2s}
.featured-article:hover .read-more::after{transform:translateX(5px)}
.article-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px;margin:28px 0 64px}
.archive-card{display:grid;grid-template-columns:180px minmax(0,1fr);gap:22px;padding:18px;background:rgba(255,255,255,.72);border:1px solid var(--line);text-decoration:none;transition:transform .2s,border-color .2s,background .2s}
.archive-card:hover{transform:translateY(-2px);border-color:rgba(46,139,120,.35);background:#fff}
.archive-card img{width:100%;height:140px;object-fit:cover;border-radius:3px}
.archive-card h3{margin:12px 0 10px;font-size:22px;line-height:1.3}
.archive-card p{margin:0;color:#5d737a;line-height:1.75;font-size:13px}
.archive-card .article-meta{margin-top:16px}
.topic-strip{display:grid;grid-template-columns:repeat(4,1fr);border:1px solid var(--line);border-right:none;margin:28px 0 80px}
.topic{min-height:140px;padding:25px;border-right:1px solid var(--line);background:rgba(255,255,255,.55)}
.topic b{display:block;color:var(--coral);font-size:12px}
.topic strong{display:block;margin-top:18px;font-size:17px}
.topic span{display:block;margin-top:8px;color:var(--muted);font-size:12px;line-height:1.55}
.knowledge-footer{padding:30px 0 44px;border-top:1px solid var(--line);color:#708288;font-size:11px;text-align:center}

/* article */
.reading-progress{position:fixed;z-index:40;top:0;left:0;height:3px;width:0;background:linear-gradient(90deg,var(--jade),var(--yellow))}
.article-header{padding:72px 0 44px;border-bottom:1px solid var(--line)}
.article-header-inner{width:min(920px,calc(100% - 40px));margin:0 auto}
.article-kicker{color:var(--jade);font-size:12px;font-weight:800;letter-spacing:.12em}
.article-header h1{margin:18px 0 22px;font-family:var(--serif);font-size:clamp(44px,6vw,72px);line-height:1.16;letter-spacing:0}
.article-deck{max-width:800px;color:#587078;font-size:18px;line-height:1.85}
.article-byline{display:flex;gap:20px;margin-top:28px;color:#74868b;font-size:12px}
.article-layout{width:min(1180px,calc(100% - 40px));margin:0 auto;display:grid;grid-template-columns:190px minmax(0,760px) 190px;gap:30px;padding:48px 0 90px;justify-content:center}
.article-toc{position:sticky;top:100px;align-self:start;border-left:1px solid var(--line);padding-left:18px}
.article-toc strong{font-size:11px;letter-spacing:.12em;color:var(--muted)}
.article-toc a{display:block;margin-top:14px;text-decoration:none;color:#61777e;font-size:12px;line-height:1.5}
.article-toc a:hover{color:var(--jade)}
.article-body{font-family:var(--serif);font-size:17px;line-height:2;color:#213d46}
.article-body .lead{font-size:20px;line-height:1.9;color:#183741}
.article-body h2{margin:52px 0 16px;font-family:var(--font);font-size:28px;line-height:1.35}
.article-body h3{margin:32px 0 10px;font-family:var(--font);font-size:20px}
.article-body p{margin:0 0 22px}
.article-body strong{color:#0a574c}
.article-figure{margin:38px 0}
.article-figure img{display:block;width:100%;border-radius:4px}
.article-figure figcaption{margin-top:10px;color:#73878d;font-family:var(--font);font-size:11px;line-height:1.6}
.plain-box{margin:32px 0;padding:25px 28px;border-left:4px solid var(--yellow);background:#fff}
.plain-box b{display:block;font-family:var(--font);font-size:13px;color:#7a5a12}
.plain-box p{margin:10px 0 0;font-size:16px;line-height:1.8}
.usage-table{width:100%;margin:30px 0 38px;border-collapse:collapse;font-family:var(--font);font-size:13px;background:#fff}
.table-scroll{width:100%;overflow-x:auto}
.usage-table th,.usage-table td{padding:16px 14px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
.usage-table th{color:#466169;font-size:11px;letter-spacing:.04em;background:#edf4f2}
.usage-table td{color:#455f67;line-height:1.65}
.usage-table td:first-child{width:22%;color:#123d47;font-weight:700}
.usage-table strong{color:var(--jade)}
.precision-note{margin:-20px 0 35px;color:#71858b;font-family:var(--font);font-size:11px;line-height:1.7}
.data-band{display:grid;grid-template-columns:repeat(3,1fr);margin:35px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.data-item{padding:22px 16px;border-right:1px solid var(--line);font-family:var(--font)}
.data-item:last-child{border-right:none}
.data-item strong{display:block;font-size:25px;color:var(--jade)}
.data-item span{display:block;margin-top:7px;color:#667c83;font-size:11px;line-height:1.5}
.side-note{position:sticky;top:100px;align-self:start;font-size:11px;line-height:1.65;color:#71858b}
.side-note strong{display:block;color:var(--coral);font-size:11px;letter-spacing:.1em;margin-bottom:9px}
.sources{margin-top:55px;padding-top:24px;border-top:1px solid var(--ink);font-family:var(--font)}
.sources h2{margin-top:0;font-size:20px}
.sources ol{padding-left:20px}
.sources li{margin:11px 0;color:#5f747b;font-size:12px;line-height:1.65}
.sources a{color:#286f74}
.next-reading{margin-top:48px;padding:28px;background:var(--ink);color:white;font-family:var(--font)}
.next-reading span{font-size:11px;color:var(--mint)}
.next-reading strong{display:block;margin-top:10px;font-size:20px}

@media(max-width:980px){
  .knowledge-hero{grid-template-columns:1fr;gap:40px}
  .hero-visual{max-width:650px}
  .article-layout{grid-template-columns:minmax(0,760px)}
  .article-toc,.side-note{display:none}
}
@media(max-width:720px){
  .knowledge-nav{height:64px;padding:0 16px}
  .brand-text span,.nav-links a:not(.home-link){display:none}
  .knowledge-shell{width:min(100% - 28px,1180px)}
  .knowledge-hero{padding:48px 0 38px}
  .hero-copy h1{font-size:48px}
  .hero-copy p{font-size:15px}
  .hero-principle{display:block}
  .hero-principle span{margin-top:10px}
  .featured-article{grid-template-columns:1fr}
  .featured-article img{aspect-ratio:16/9}
  .featured-copy{padding:28px 24px}
  .featured-copy h3{font-size:28px}
  .article-grid{grid-template-columns:1fr}
  .archive-card{grid-template-columns:1fr}
  .archive-card img{height:auto;aspect-ratio:16/9}
  .topic-strip{grid-template-columns:1fr 1fr}
  .topic{border-bottom:1px solid var(--line)}
  .article-header{padding:48px 0 32px}
  .article-header h1{font-size:42px}
  .article-deck{font-size:16px}
  .article-layout{width:min(100% - 30px,760px);padding-top:30px}
  .article-body{font-size:16px;line-height:1.95}
  .article-body .lead{font-size:18px}
  .data-band{grid-template-columns:1fr}
  .data-item{border-right:none;border-bottom:1px solid var(--line)}
  .data-item:last-child{border-bottom:none}
  .usage-table{min-width:680px}
}
@media(max-width:420px){
  .topic-strip{grid-template-columns:1fr}
  .hero-copy h1{font-size:40px}
  .article-header h1{font-size:36px}
}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}