:root{
  --bg:#ffffff;
  --bg-soft:#f6f8f9;
  --bg-card:#ffffff;
  --text:#1f2933;
  --text-soft:#52606d;
  --text-mute:#7b8794;
  --primary:#0f766e;
  --primary-dark:#0b5a54;
  --primary-soft:#e6f4f1;
  --accent:#b45309;
  --border:#e4e7eb;
  --radius:14px;
  --shadow:0 6px 24px rgba(15,118,110,.08);
  --maxw:1080px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC",sans-serif;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--bg-soft);color:var(--text);
  font-family:var(--font);line-height:1.75;font-size:17px;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto;display:block}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{line-height:1.4;color:var(--text);font-weight:700}
h1{font-size:30px;margin:.2em 0 .5em}
h2{font-size:24px;margin:1.8em 0 .6em;padding-bottom:.3em;border-bottom:2px solid var(--primary-soft)}
h3{font-size:19px;margin:1.4em 0 .5em;color:var(--primary-dark)}
p{margin:.8em 0}
ul,ol{padding-left:1.4em;margin:.8em 0}
li{margin:.35em 0}
blockquote{margin:1.2em 0;padding:.8em 1.1em;background:var(--primary-soft);border-left:4px solid var(--primary);border-radius:8px;color:var(--text-soft)}
code{background:var(--bg-soft);padding:.1em .4em;border-radius:4px;font-size:.92em}

/* layout */
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 18px}
.site-header{background:var(--bg);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:50;box-shadow:0 1px 0 rgba(0,0,0,.02)}
.nav{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:20px;color:var(--primary)}
.brand .dot{width:12px;height:12px;border-radius:50%;background:var(--primary);display:inline-block}
.nav-links{display:flex;gap:22px;list-style:none;margin:0;padding:0;align-items:center}
.nav-links a{color:var(--text-soft);font-size:15px;font-weight:600}
.nav-links a:hover{color:var(--primary);text-decoration:none}
.nav-toggle{display:none;background:none;border:0;font-size:24px;color:var(--primary);cursor:pointer}

/* hero */
.hero{background:linear-gradient(135deg,#0f766e,#138a7e);color:#fff;padding:54px 0 48px}
.hero h1{color:#fff;font-size:34px;margin:0 0 .4em}
.hero p{color:#d7f0ec;font-size:18px;max-width:680px;margin:0}
.hero .tags{margin-top:18px;display:flex;flex-wrap:wrap;gap:8px}
.hero .tags span{background:rgba(255,255,255,.16);padding:5px 12px;border-radius:999px;font-size:13px}

/* sections */
.section{padding:38px 0}
.section h2.section-title{font-size:22px;border:0;margin:0 0 18px;display:flex;align-items:center;gap:10px}
.section-title::before{content:"";width:6px;height:22px;background:var(--primary);border-radius:3px;display:inline-block}
.muted{color:var(--text-mute)}

/* cards */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:18px}
.card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);display:flex;flex-direction:column;transition:transform .15s ease,box-shadow .15s ease}
.card:hover{transform:translateY(-3px);box-shadow:0 10px 30px rgba(15,118,110,.14)}
.card .thumb{aspect-ratio:16/9;background:linear-gradient(135deg,#e6f4f1,#cdeadc);display:flex;align-items:center;justify-content:center;color:var(--primary);font-weight:700;font-size:15px;text-align:center;padding:12px}
.card .body{padding:16px 18px 20px;display:flex;flex-direction:column;flex:1}
.card .cat{font-size:12px;color:var(--accent);font-weight:700;letter-spacing:.04em}
.card h3{font-size:18px;margin:.3em 0 .4em}
.card h3 a{color:var(--text)}
.card .excerpt{color:var(--text-soft);font-size:14.5px;flex:1}
.card .meta{margin-top:12px;font-size:12.5px;color:var(--text-mute);display:flex;gap:12px}

/* article page */
.article{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);margin:26px auto;max-width:820px;padding:30px 34px 40px}
.breadcrumb{font-size:13px;color:var(--text-mute);margin:18px auto 0;max-width:820px;padding:0 18px}
.breadcrumb a{color:var(--text-soft)}
.article .post-meta{font-size:13.5px;color:var(--text-mute);margin:.4em 0 1.2em;display:flex;flex-wrap:wrap;gap:14px}
.article .lead{font-size:18px;color:var(--text-soft)}
.key-points{background:var(--primary-soft);border:1px solid #bfe3dc;border-radius:12px;padding:16px 20px;margin:22px 0}
.key-points h3{margin-top:0;color:var(--primary-dark)}
.key-points ul{margin:.4em 0}
.figure{margin:24px 0}
.figure .ph{background:linear-gradient(135deg,#e6f4f1,#cdeadc);border-radius:12px;aspect-ratio:16/9;display:flex;align-items:center;justify-content:center;color:var(--primary-dark);font-weight:600;text-align:center;padding:16px;border:1px dashed #9fcabf}
.figure figcaption{font-size:13px;color:var(--text-mute);margin-top:8px;text-align:center}

/* tables */
table{border-collapse:collapse;width:100%;margin:20px 0;font-size:15px;background:var(--bg-card);border-radius:10px;overflow:hidden;box-shadow:var(--shadow)}
th,td{border:1px solid var(--border);padding:10px 12px;text-align:left;vertical-align:top}
thead th{background:var(--primary);color:#fff;font-weight:700}
tbody tr:nth-child(even){background:var(--bg-soft)}

/* callout */
.note{background:#fff7ed;border:1px solid #fed7aa;border-left:4px solid var(--accent);border-radius:8px;padding:12px 16px;margin:18px 0;color:#7c2d12}

/* related */
.related{margin:30px auto;max-width:820px;padding:0 18px}
.related h3{font-size:18px}
.related ul{list-style:none;padding:0;display:grid;gap:10px}
.related a{display:block;background:var(--bg-card);border:1px solid var(--border);border-radius:10px;padding:12px 16px;color:var(--text);font-weight:600}
.related a:hover{background:var(--primary-soft);text-decoration:none}

/* footer */
.site-footer{background:var(--text);color:#cbd5e0;margin-top:40px;padding:34px 0;font-size:14px}
.site-footer a{color:#9fe3d6}
.site-footer .cols{display:flex;flex-wrap:wrap;gap:30px;justify-content:space-between}
.site-footer h4{color:#fff;font-size:15px;margin:0 0 10px}
.site-footer ul{list-style:none;padding:0;margin:0}
.site-footer li{margin:.3em 0}
.foot-bottom{border-top:1px solid #2d3748;margin-top:24px;padding-top:16px;color:#8a98a8;font-size:13px}

/* 404 */
.notfound{text-align:center;padding:80px 20px}
.notfound h1{font-size:64px;color:var(--primary)}

/* responsive */
@media (max-width:760px){
  body{font-size:16px}
  .nav-links{position:absolute;top:60px;left:0;right:0;background:var(--bg);border-bottom:1px solid var(--border);flex-direction:column;gap:0;padding:8px 18px;display:none}
  .nav-links.open{display:flex}
  .nav-links a{padding:12px 0;border-bottom:1px solid var(--border);width:100%}
  .nav-toggle{display:block}
  .hero h1{font-size:27px}
  h1{font-size:25px}
  h2{font-size:21px}
  .article{padding:22px 18px 30px;border-radius:0;border-left:0;border-right:0}
  table{font-size:13.5px}
  th,td{padding:8px 9px}
}