:root{
  --ink:#1b1e23;
  --ink-2:#3d434d;
  --gray:#6b7280;
  --line:#dfdbd4;
  --bg:#f6f4f0;
  --card:#ffffff;
  --rust:#c14c19;
  --rust-d:#9c3a10;
  --green:#1f7a45;
  --steel:#eceae5;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.72;font-size:16px;
}
a{color:inherit;text-decoration:none}
.wrap{width:100%;max-width:1120px;margin:0 auto;padding:0 20px}
.sr-only{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}

/* header */
header{
  position:sticky;top:0;z-index:50;background:rgba(246,244,240,.95);
  backdrop-filter:blur(8px);border-bottom:1px solid var(--line);
}
.nav{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.brand{display:flex;align-items:baseline;gap:8px;font-weight:800;font-size:19px;letter-spacing:.5px;white-space:nowrap;flex-shrink:0}
.brand em{font-style:normal;color:var(--rust)}
.brand span{font-size:12px;font-weight:500;color:var(--gray);letter-spacing:1px}
.nav-links{display:flex;gap:24px;font-size:15px;color:var(--ink-2);white-space:nowrap;flex-shrink:0}
.nav-links a:hover{color:var(--rust)}
.nav-links a.on{color:var(--rust);font-weight:700}
.nav-tels{display:flex;align-items:center;gap:8px}
.nav-tel{
  display:inline-flex;align-items:center;gap:8px;background:var(--ink);color:#fff;
  padding:10px 18px;border-radius:4px;font-weight:700;font-size:15px;white-space:nowrap;
}
.nav-tel:hover{background:var(--rust)}

/* article hero */
.art-hero{background:#fff;border-bottom:1px solid var(--line);padding:44px 0 34px}
.crumb{font-size:13.5px;color:var(--gray);margin-bottom:18px;letter-spacing:.3px}
.crumb a:hover{color:var(--rust)}
.crumb i{font-style:normal;margin:0 7px;color:#c3bdb4}
.art-hero h1{font-size:38px;line-height:1.3;font-weight:800;letter-spacing:-.4px;max-width:860px}
.art-meta{margin-top:16px;font-size:13.5px;color:var(--gray);display:flex;flex-wrap:wrap;gap:18px}
.art-meta b{color:var(--ink-2);font-weight:600}
.art-lead{margin-top:20px;font-size:17.5px;line-height:1.85;color:var(--ink-2);max-width:820px}
.art-lead strong{color:var(--ink)}

/* layout */
.art-wrap{display:grid;grid-template-columns:1fr 300px;gap:48px;align-items:start;padding:48px 0 64px}
.art-body{min-width:0;font-size:17px;line-height:1.95;color:var(--ink-2)}
.art-body p{margin:0 0 20px}
.art-body strong{color:var(--ink);font-weight:700}
.art-body h2{
  font-size:25px;line-height:1.45;font-weight:800;color:var(--ink);
  margin:44px 0 16px;padding-left:14px;border-left:4px solid var(--rust);letter-spacing:-.2px;
}
.art-body h2:first-child{margin-top:0}
.art-body h3{font-size:18.5px;font-weight:700;color:var(--ink);margin:30px 0 10px}
.art-body ul,.art-body ol{margin:0 0 20px;padding-left:22px}
.art-body li{margin-bottom:9px}
.art-body a.link{color:var(--rust);border-bottom:1px solid rgba(193,76,25,.35)}
.art-body a.link:hover{border-bottom-color:var(--rust)}

/* answer box */
.answer{
  background:#fdf6ec;border:1px solid #efdcc2;border-left:4px solid var(--rust);
  border-radius:0 6px 6px 0;padding:22px 24px;margin:0 0 28px;
}
.answer .t{font-size:12.5px;font-weight:800;letter-spacing:2px;color:var(--rust);margin-bottom:10px}
.answer p{font-size:16.5px;line-height:1.9;color:var(--ink);margin:0}
.answer p + p{margin-top:12px}

/* key points */
.keypoints{background:#fff;border:1px solid var(--line);border-radius:6px;padding:22px 26px;margin:0 0 30px}
.keypoints h3{font-size:14px;letter-spacing:1.5px;color:var(--gray);margin:0 0 14px;font-weight:700}
.keypoints ul{margin:0;padding-left:0;list-style:none}
.keypoints li{position:relative;padding-left:24px;font-size:16px;line-height:1.8;margin-bottom:10px;color:var(--ink-2)}
.keypoints li:last-child{margin-bottom:0}
.keypoints li:before{content:"";position:absolute;left:0;top:10px;width:8px;height:8px;background:var(--rust);border-radius:1px}
.keypoints li b{color:var(--ink)}

/* table */
.tbl-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;border:1px solid var(--line);border-radius:6px;background:#fff;margin:0 0 14px}
table{width:100%;border-collapse:collapse;font-size:15.5px;min-width:560px}
thead th{background:var(--ink);color:#fff;text-align:left;padding:14px 16px;font-weight:600;font-size:14px;letter-spacing:.5px;white-space:nowrap}
tbody td{padding:14px 16px;border-top:1px solid var(--line);color:var(--ink-2);vertical-align:top;line-height:1.75}
tbody tr:nth-child(even){background:#fbfaf8}
tbody td:first-child{color:var(--ink);font-weight:700}
.tbl-note{margin:0 0 26px;font-size:13.5px;color:var(--gray);line-height:1.85}
.num{font-family:ui-monospace,Menlo,Consolas,monospace;white-space:nowrap}

/* figure */
figure.art-fig{margin:26px 0}
figure.art-fig img{width:100%;aspect-ratio:16/10;object-fit:cover;object-position:center 45%;display:block;border-radius:6px;background:var(--steel)}
figure.art-fig figcaption{margin-top:10px;font-size:13.5px;color:var(--gray);line-height:1.8}

/* formula / callout */
.callout{background:#fff;border:1px solid var(--line);border-left:4px solid var(--green);border-radius:0 6px 6px 0;padding:20px 24px;margin:0 0 26px}
.callout h3{margin:0 0 10px;font-size:17px}
.callout p{font-size:16px;line-height:1.9;margin:0 0 10px}
.callout p:last-child{margin-bottom:0}
.eq{background:#f2efe9;border-radius:6px;padding:16px 18px;font-size:14.5px;line-height:2;color:var(--ink-2);margin:12px 0;font-family:ui-monospace,Menlo,Consolas,monospace}
.eq b{color:var(--rust);font-weight:700}

/* faq */
.faq-block{margin-top:44px}
.faq-block > h2{margin-top:0}
.qa{background:#fff;border:1px solid var(--line);border-radius:6px;padding:20px 24px;margin-bottom:12px}
.qa h3{margin:0 0 10px;font-size:17px;line-height:1.6}
.qa h3:before{content:"问：";color:var(--rust)}
.qa p{font-size:16px;line-height:1.9;color:var(--ink-2);margin:0}
.qa p + p{margin-top:10px}

/* aside */
.aside{position:sticky;top:88px;font-size:15px}
.aside-card{background:#fff;border:1px solid var(--line);border-radius:6px;padding:22px 22px;margin-bottom:16px}
.aside-card h3{font-size:14px;letter-spacing:1.2px;color:var(--gray);font-weight:700;margin-bottom:14px}
.aside-card .tel{display:block;font-size:21px;font-weight:800;color:var(--ink);letter-spacing:.5px;margin-bottom:6px}
.aside-card .tel:hover{color:var(--rust)}
.aside-card p{font-size:13.8px;color:var(--gray);line-height:1.85;margin:0}
.aside-card p + p{margin-top:8px}
.aside-card .cta{
  display:block;text-align:center;background:var(--rust);color:#fff;border-radius:4px;
  padding:13px 10px;font-weight:700;font-size:15.5px;margin-top:16px;
}
.aside-card .cta:hover{background:var(--rust-d)}
.aside-list{list-style:none;padding:0;margin:0}
.aside-list li{padding:11px 0;border-top:1px solid #f0ece6;font-size:15px;line-height:1.65}
.aside-list li:first-child{border-top:0;padding-top:0}
.aside-list a:hover{color:var(--rust)}
.aside-list span{display:block;font-size:12.5px;color:var(--gray);margin-top:2px}

/* related */
.related{background:#fff;border-top:1px solid var(--line);padding:46px 0}
.related h2{font-size:22px;font-weight:800;margin-bottom:20px}
.rel-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.rel{background:var(--bg);border:1px solid var(--line);border-radius:6px;padding:20px 20px;transition:.18s}
.rel:hover{border-color:var(--rust);background:#fff}
.rel .k{font-size:12.5px;color:var(--rust);font-weight:700;letter-spacing:1px;margin-bottom:8px}
.rel h3{font-size:16.5px;font-weight:700;line-height:1.55;margin-bottom:8px}
.rel p{font-size:13.8px;color:var(--gray);line-height:1.7;margin:0}

/* footer */
footer{background:#15181d;color:#8d949f;padding:36px 0;font-size:13.5px;line-height:2}
footer .fbrand{color:#fff;font-weight:800;font-size:16px;margin-bottom:10px}
footer .fbrand em{font-style:normal;color:#f08a4b}
footer .mono{font-family:ui-monospace,Menlo,Consolas,monospace;color:#c9cdd4;letter-spacing:.3px}
footer .frow{display:flex;justify-content:space-between;flex-wrap:wrap;gap:16px;margin-top:20px;padding-top:18px;border-top:1px solid #262a31;font-size:12.5px}
footer a:hover{color:#f08a4b}

/* mobile */
.mbar{display:none}
@media(max-width:1150px){
  .nav-links{gap:15px;font-size:14px}
  .nav-tel{padding:8px 10px;font-size:13px}
  .brand{font-size:17px}
}
@media(max-width:960px){
  .art-wrap{grid-template-columns:1fr;gap:34px;padding:34px 0 48px}
  .aside{position:static}
  .rel-grid{grid-template-columns:1fr}
}
@media(max-width:880px){
  .art-hero{padding:30px 0 26px}
  .art-hero h1{font-size:26px}
  .art-lead{font-size:16.5px}
  .art-body{font-size:16.5px;line-height:1.9}
  .art-body h2{font-size:21px;margin:34px 0 14px}
  .nav-links{display:none}
  .nav-tel-2nd{display:none}
  .brand span{display:none}
  .nav-tel{padding:9px 14px;font-size:14px}
  .answer{padding:18px 18px}
  .keypoints{padding:18px 20px}
  body{padding-bottom:64px}
  .mbar{
    display:flex;position:fixed;bottom:0;left:0;right:0;z-index:60;
    background:#fff;border-top:1px solid var(--line);box-shadow:0 -4px 16px rgba(0,0,0,.08);
  }
  .mbar a{flex:1;text-align:center;padding:13px 6px;font-weight:700;font-size:13.5px;white-space:nowrap;letter-spacing:-.2px}
  .mbar a:first-child{color:var(--ink)}
  .mbar a:nth-child(2){background:var(--rust);color:#fff;box-shadow:inset -1px 0 0 rgba(255,255,255,.3)}
  .mbar a:last-child{background:var(--rust);color:#fff}
}
@media(max-width:420px){
  .art-hero h1{font-size:23px}
  .wrap{padding:0 16px}
}