@font-face {
  font-family: 'Inter';
  src: url('/assets/fonts/inter-latin.woff2') format('woff2');
  font-weight: 100 900;
  font-display: swap;
}
:root{--ink:#10182E; --ink-2:#3D4A63; --ink-3:#5A6B85; --page:#F4F6FB; --card:#FFFFFF; --line:#E2E7F0; --tint:#FBFCFE; --band:#0E1B4D; --band-2:#1A2B7A; --on-band:#FFFFFF; --on-band-muted:#B9C3E8; --primary:#1D2E8F; --primary-hover:#16246F; --primary-soft:#E8EBFA; --green:#0B7A54; --green-deep:#075C40; --green-soft:#E4F4EC; --green-line:#BFE3D2; --amber-bg:#FFF4E0; --amber-ink:#7A4E00; --r-lg:16px; --r-md:12px; --r-sm:8px; --shadow:0 1px 2px rgba(16,24,46,.05),0 8px 24px rgba(16,24,46,.07); --shadow-lg:0 2px 8px rgba(16,24,46,.06),0 12px 40px rgba(16,24,46,.14);}
*{margin:0;padding:0;box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{font-family:Inter,ui-sans-serif,-apple-system,"SF Pro Text","Segoe UI",Roboto,sans-serif; background:var(--page);color:var(--ink);line-height:1.55;font-size:16px;-webkit-font-smoothing:antialiased}
.num{font-variant-numeric:tabular-nums lining-nums}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:1160px;margin:0 auto;padding:0 24px}
/* ---------- header ---------- */ header.top{background:var(--card);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
.top-in{display:flex;align-items:center;gap:32px;height:64px}
.wordmark{font-weight:800;font-size:19px;letter-spacing:-.02em;color:var(--ink);display:flex;align-items:center;gap:9px}
.wordmark svg{width:22px;height:22px}
.wordmark:hover{text-decoration:none}
nav.main{display:flex;gap:4px;margin-left:8px}
nav.main a{color:var(--ink-2);font-size:14px;font-weight:500;padding:8px 12px;border-radius:8px}
nav.main a:hover{background:var(--page);text-decoration:none;color:var(--ink)}
nav.main a.on{color:var(--primary);background:var(--primary-soft)}
.top-cta{margin-left:auto;font-size:14px;font-weight:600;color:var(--primary);padding:9px 16px;border:1px solid var(--line);border-radius:999px;background:var(--card)}
.top-cta:hover{background:var(--primary-soft);text-decoration:none}
/* ---------- hero band ---------- */ .band{background:linear-gradient(160deg,var(--band) 0%,var(--band-2) 78%,#1E3190 100%);color:var(--on-band);position:relative;overflow:hidden}
.band::after{content:"";position:absolute;right:-160px;top:-220px;width:640px;height:640px;border-radius:50%; background:radial-gradient(circle,rgba(84,110,255,.35) 0%,rgba(84,110,255,0) 66%)}
.band-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:56px;padding:72px 0 84px;position:relative;z-index:1}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font-size:12.5px;font-weight:600;letter-spacing:.08em;text-transform:uppercase; color:#9FE8C9;background:rgba(159,232,201,.10);border:1px solid rgba(159,232,201,.28);padding:6px 14px;border-radius:999px}
.eyebrow .dot{width:7px;height:7px;border-radius:50%;background:#3ED598}
h1.display{font-size:52px;line-height:1.06;font-weight:800;letter-spacing:-.035em;margin:22px 0 18px;max-width:12ch}
.lede{font-size:18px;line-height:1.6;color:var(--on-band-muted);max-width:46ch}
.hero-trust{display:flex;gap:10px;flex-wrap:wrap;margin-top:28px}
.tchip{display:inline-flex;align-items:center;gap:7px;font-size:13.5px;font-weight:500;color:#DCE3FA; border:1px solid rgba(185,195,232,.34);border-radius:999px;padding:8px 15px;background:rgba(255,255,255,.05)}
.tchip svg{width:15px;height:15px;color:#3ED598}
/* ---------- hero estimator card ---------- */ .est{background:var(--card);color:var(--ink);border-radius:var(--r-lg);box-shadow:var(--shadow-lg);padding:28px 28px 24px}
.est-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}
.est-title{font-size:13px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;color:var(--ink-3)}
.verified{display:inline-flex;align-items:center;gap:6px;font-size:12px;font-weight:600;color:var(--green); background:var(--green-soft);padding:5px 11px;border-radius:999px}
.verified svg{width:13px;height:13px}
.est-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.fld label{display:block;font-size:13px;font-weight:600;color:var(--ink-2);margin-bottom:6px}
.fld .ctl{width:100%;border:1px solid var(--line);border-radius:var(--r-sm);padding:11px 13px;font-size:15px;font-weight:500; color:var(--ink);background:#FBFCFE;font-family:inherit}
.est-out{margin-top:22px;border-top:1px dashed var(--line);padding-top:20px;display:flex;align-items:flex-end;justify-content:space-between;gap:16px}
.est-out .lbl{font-size:13px;font-weight:600;color:var(--ink-3)}
.big{font-size:56px;font-weight:800;letter-spacing:-.04em;color:var(--green-deep);line-height:1;font-variant-numeric:tabular-nums}
.big small{font-size:22px;font-weight:700;vertical-align:12px;letter-spacing:-.02em}
.est-note{font-size:12.5px;color:var(--ink-3);max-width:22ch;text-align:right}
.est-cta{display:inline-block;margin-top:16px;width:100%;text-align:center;background:var(--primary);color:#fff;font-weight:600; font-size:15px;padding:13px;border-radius:10px}
.est-cta:hover{background:var(--primary-hover);text-decoration:none}
/* ---------- tool matrix ---------- */ .sec{padding:72px 0}
.sec.alt{background:var(--card);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.kicker{font-size:12.5px;font-weight:700;letter-spacing:.09em;text-transform:uppercase;color:var(--primary)}
h2.sec-title{font-size:34px;font-weight:800;letter-spacing:-.03em;margin:10px 0 12px}
.sec-sub{color:var(--ink-2);max-width:60ch;font-size:16px}
.grid8{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-top:36px}
.tool{background:var(--card);border:1px solid var(--line);border-radius:var(--r-md);padding:22px 20px;display:block;position:relative;transition:box-shadow .15s}
.tool:hover{box-shadow:var(--shadow);text-decoration:none;border-color:#C9D2E6}
.tool .ico{width:38px;height:38px;border-radius:10px;background:var(--primary-soft);color:var(--primary);display:flex;align-items:center;justify-content:center;margin-bottom:14px}
.tool .ico svg{width:19px;height:19px}
.tool.flag .ico{background:var(--green-soft);color:var(--green)}
.tool h3{font-size:16px;font-weight:700;letter-spacing:-.015em;color:var(--ink)}
.tool p{font-size:13.5px;color:var(--ink-3);margin-top:5px;line-height:1.45}
.tool .go{font-size:13px;font-weight:600;color:var(--primary);margin-top:12px;display:inline-flex;align-items:center;gap:5px}
/* ---------- how it works ---------- */ .steps{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin-top:36px}
.step{background:var(--card);border:1px solid var(--line);border-radius:var(--r-md);padding:26px 24px}
.step .n{width:34px;height:34px;border-radius:50%;background:var(--band);color:#fff;font-weight:700;font-size:15px;display:flex;align-items:center;justify-content:center;margin-bottom:16px}
.step h3{font-size:17px;font-weight:700;letter-spacing:-.015em}
.step p{font-size:14.5px;color:var(--ink-2);margin-top:8px;line-height:1.55}
/* ---------- FAQ ---------- */ .faq{margin-top:32px;max-width:780px}
details.q{background:var(--card);border:1px solid var(--line);border-radius:var(--r-md);margin-bottom:12px}
details.q summary{cursor:pointer;list-style:none;padding:18px 22px;font-weight:600;font-size:15.5px;display:flex;justify-content:space-between;align-items:center}
details.q summary::-webkit-details-marker{display:none}
details.q summary::after{content:"+";font-size:20px;color:var(--ink-3);font-weight:400}
details.q[open] summary::after{content:"–"}
details.q .a{padding:0 22px 18px;color:var(--ink-2);font-size:14.5px;line-height:1.6}
/* ---------- footer ---------- */ footer{background:var(--band);color:var(--on-band-muted);margin-top:0}
.ft{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:32px;padding:56px 0 40px}
.ft h4{color:#fff;font-size:13px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;margin-bottom:14px}
.ft a{display:block;color:var(--on-band-muted);font-size:14px;padding:4px 0}
.ft a:hover{color:#fff;text-decoration:none}
.ft .wm{font-weight:800;font-size:18px;color:#fff;letter-spacing:-.02em}
.ft .tag{font-size:13.5px;margin-top:10px;max-width:30ch;line-height:1.6}
.ft-bar{border-top:1px solid rgba(185,195,232,.18);padding:18px 0;font-size:13px;display:flex;justify-content:space-between;gap:16px}
header.top{background:var(--card);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
.crumbs{font-size:13px;color:var(--ink-3);padding:20px 0 0}
.crumbs a{color:var(--ink-3)}
.pagehead{padding:16px 0 24px;display:flex;justify-content:space-between;align-items:flex-end;gap:24px;flex-wrap:wrap}
h1{font-size:38px;font-weight:800;letter-spacing:-.03em}
.h1sub{color:var(--ink-2);margin-top:8px;max-width:70ch;font-size:16px}
.calc{display:grid;grid-template-columns:430px 1fr;gap:24px;align-items:start}
/* ---------- inputs card ---------- */ .card{background:var(--card);border:1px solid var(--line);border-radius:var(--r-lg);box-shadow:var(--shadow)}
.in-card{padding:24px}
.card-h{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}
.card-t{font-size:13px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;color:var(--ink-3)}
.seg{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;background:var(--page);border:1px solid var(--line);border-radius:10px;padding:5px}
.seg button{border:0;background:transparent;font:inherit;font-size:13px;font-weight:600;color:var(--ink-2);padding:9px 4px;border-radius:7px;cursor:pointer}
.seg button.on{background:var(--band);color:#fff}
.fld{margin-top:16px}
.fld .hint{font-size:12px;color:var(--ink-3);margin-top:5px}
.ctl{width:100%;border:1px solid var(--line);border-radius:var(--r-sm);padding:11px 13px;font-size:15px;font-weight:500;color:var(--ink);background:var(--tint);font-family:inherit}
.money{position:relative}
.money .ctl{padding-left:30px;font-variant-numeric:tabular-nums}
.money::before{content:"$";position:absolute;left:12px;top:11px;color:var(--ink-3);font-size:15px;font-weight:600}
select.ctl{appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%235A6B85' stroke-width='2' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 13px center}
details.obb{margin-top:18px;border:1px solid var(--line);border-radius:10px;background:var(--tint)}
details.obb summary{cursor:pointer;list-style:none;padding:14px 16px;font-size:14px;font-weight:600;display:flex;justify-content:space-between;align-items:center}
details.obb summary::-webkit-details-marker{display:none}
details.obb summary::after{content:"+";font-size:18px;color:var(--ink-3);font-weight:400}
details.obb[open] summary::after{content:"–"}
details.obb .in{padding:0 16px 14px}
.obb-note{font-size:12.5px;color:var(--ink-3);margin-bottom:12px;line-height:1.5}
.snap{margin-top:18px;width:100%;text-align:center;border:1px dashed #C9D2E6;color:var(--ink-2);font-weight:600;font-size:14px;padding:12px;border-radius:10px;background:var(--tint)}
/* ---------- results ---------- */ .res-card{overflow:hidden}
.res-hero{background:linear-gradient(150deg,var(--band) 0%,#182866 90%);color:#fff;padding:28px 28px 26px}
.res-hero .lbl{font-size:13px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--on-band-muted)}
.res-big{font-size:68px;font-weight:800;letter-spacing:-.045em;line-height:1.05;margin-top:8px;font-variant-numeric:tabular-nums}
.res-big small{font-size:28px;font-weight:700;vertical-align:20px}
.res-hero .sub{font-size:13.5px;color:var(--on-band-muted);margin-top:10px}
.split{display:grid;grid-template-columns:1fr 1fr;border-top:1px solid var(--line)}
.blk{padding:22px 24px}
.blk + .blk{border-left:1px solid var(--line)}
.blk .t{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--ink-3)}
.pill{font-size:11px;font-weight:700;letter-spacing:.03em;padding:3px 9px;border-radius:999px;text-transform:none}
.pill.adj{background:var(--primary-soft);color:var(--primary)}
.pill.file{background:var(--green-soft);color:var(--green-deep)}
.blk .amt{font-size:36px;font-weight:800;letter-spacing:-.035em;margin-top:10px;font-variant-numeric:tabular-nums}
.blk.pos .amt{color:var(--green-deep)}
.blk .d{font-size:13px;color:var(--ink-2);margin-top:8px;line-height:1.5}
.blk .d b{color:var(--ink)}
.w4tip{margin-top:14px;background:var(--primary-soft);border-radius:10px;padding:12px 14px;font-size:13px;line-height:1.5;color:#26336E}
.w4tip b{color:var(--primary)}
/* ---------- formula + constants ---------- */ .lower{padding:6px 24px 24px}
details.formula{border:1px solid var(--line);border-radius:12px;margin-top:16px;background:var(--tint)}
details.formula summary{cursor:pointer;list-style:none;padding:15px 18px;font-weight:600;font-size:14.5px;display:flex;justify-content:space-between;align-items:center}
details.formula summary::-webkit-details-marker{display:none}
details.formula summary::after{content:"+";font-size:18px;color:var(--ink-3);font-weight:400}
details.formula[open] summary::after{content:"–"}
.frows{padding:2px 18px 16px}
.frow{display:flex;justify-content:space-between;gap:16px;padding:9px 0;border-bottom:1px dashed var(--line);font-size:14px}
.frow:last-child{border-bottom:0}
.frow .k{color:var(--ink-2)}
.frow .v{font-weight:600;font-variant-numeric:tabular-nums;white-space:nowrap}
.frow.total .v{color:var(--green-deep);font-weight:800}
.const{margin-top:16px;border:1px solid var(--green-line);background:var(--green-soft);border-radius:12px;padding:16px 18px}
.const .t{display:flex;align-items:center;gap:8px;font-size:12.5px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--green-deep)}
.const .t svg{width:15px;height:15px}
.const ul{list-style:none;margin-top:10px}
.const li{font-size:13px;color:#14463A;padding:3px 0;display:flex;gap:8px}
.const li::before{content:"—";color:var(--green)}
.disclaim{margin-top:14px;font-size:12.5px;color:var(--amber-ink);background:var(--amber-bg);border-radius:10px;padding:11px 14px;line-height:1.5}
/* ---------- below the fold ---------- */ .prose{display:grid;grid-template-columns:1fr 340px;gap:24px;margin-top:40px}
.prose .body h2{font-size:26px;font-weight:800;letter-spacing:-.02em;margin:28px 0 12px}
.prose .body p{color:var(--ink-2);margin-bottom:12px;font-size:15.5px;line-height:1.65}
.rel{padding:22px;position:sticky;top:88px}
.rel h3{font-size:13px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;color:var(--ink-3);margin-bottom:12px}
.rel a{display:block;padding:10px 0;border-bottom:1px solid var(--line);font-weight:600;font-size:14.5px}
.rel a span{display:block;font-weight:400;font-size:13px;color:var(--ink-3);margin-top:2px}
footer{background:var(--band);color:var(--on-band-muted);margin-top:72px}
.byline{display:flex;gap:10px;align-items:center;margin-top:14px;font-size:13.5px;color:var(--ink-3)}
.byline .who{font-weight:700;color:var(--ink-2)}
.byline img{width:30px;height:30px;border-radius:50%;background:var(--primary-soft);display:inline-block}
/* year tabs */ .ytabs{display:inline-flex;background:var(--card);border:1px solid var(--line);border-radius:999px;padding:4px;gap:2px}
.ytabs a{font-size:14px;font-weight:600;color:var(--ink-2);padding:8px 20px;border-radius:999px}
.ytabs a:hover{text-decoration:none;background:var(--page)}
.ytabs a.on{background:var(--band);color:#fff}
.grid{display:grid;grid-template-columns:1fr 320px;gap:24px;align-items:start;margin-top:24px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r-lg);box-shadow:var(--shadow)}
/* tables */ .tcard{padding:22px 24px;margin-bottom:20px}
.tcard h2{font-size:19px;font-weight:800;letter-spacing:-.02em;margin-bottom:4px}
.tcard .src{font-size:12.5px;color:var(--ink-3);margin-bottom:14px}
table{width:100%;border-collapse:collapse;font-size:14px}
th{font-size:11.5px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;color:var(--ink-3);text-align:left; padding:9px 12px;border-bottom:2px solid var(--line)}
td{padding:9px 12px;border-bottom:1px solid var(--line);color:var(--ink-2);font-variant-numeric:tabular-nums}
tr:last-child td{border-bottom:0}
td.rate{font-weight:800;color:var(--ink);white-space:nowrap}
td.zone{font-weight:600;color:var(--ink)}
tr.hl td{background:var(--green-soft)}
.tbl-scroll{overflow-x:auto}
/* marginal/effective cards */ .mecards{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:22px 0}
.mec{padding:20px 22px}
.mec .t{font-size:12.5px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;color:var(--ink-3)}
.mec .big{font-size:34px;font-weight:800;letter-spacing:-.03em;margin-top:8px;font-variant-numeric:tabular-nums}
.mec p{font-size:13.5px;color:var(--ink-2);margin-top:8px;line-height:1.55}
.mec.g .big{color:var(--green-deep)}
/* worked example */ .example{background:linear-gradient(150deg,var(--band) 0%,#182866 92%);color:#fff;border-radius:var(--r-lg);padding:26px 28px;margin:22px 0}
.example .t{font-size:12.5px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:#9FE8C9;display:flex;align-items:center;gap:8px}
.example h3{font-size:22px;font-weight:800;letter-spacing:-.02em;margin:10px 0 6px}
.example .row{display:flex;justify-content:space-between;gap:16px;padding:8px 0;border-bottom:1px dashed rgba(185,195,232,.3);font-size:14.5px;color:#DCE3FA}
.example .row .v{font-weight:600;color:#fff;font-variant-numeric:tabular-nums;white-space:nowrap}
.example .row.total{border-bottom:0}
.example .row.total .v{color:#3ED598;font-size:17px;font-weight:800}
.example .fnote{font-size:12.5px;color:var(--on-band-muted);margin-top:12px}
.note{background:var(--amber-bg);color:var(--amber-ink);border-radius:12px;padding:14px 18px;font-size:13.5px;line-height:1.55;margin:16px 0}
.body-copy p{color:var(--ink-2);margin:12px 0;font-size:15.5px;line-height:1.65}
.body-copy h2{font-size:24px;font-weight:800;letter-spacing:-.02em;margin:28px 0 10px}
.body-copy ul{margin:8px 0 12px 20px;color:var(--ink-2);font-size:15px;line-height:1.6}
.rel .cta{display:block;margin-top:16px;text-align:center;background:var(--primary);color:#fff;font-weight:600;font-size:14px;padding:12px;border-radius:10px}
.rel .cta:hover{background:#16237A;text-decoration:none}
.rel .vd{display:inline-flex;align-items:center;gap:6px;font-size:12px;font-weight:600;color:var(--green);background:var(--green-soft);padding:5px 11px;border-radius:999px;margin-bottom:12px}
.rel .vd svg{width:12px;height:12px}
/* ---------- 实现补充（设计稿未覆盖） ---------- */
.note{font-size:13.5px;color:var(--amber-ink);background:var(--amber-bg);border-radius:10px;padding:12px 14px;line-height:1.55}
.engine-example{border:1px solid var(--line);border-radius:var(--r-lg);background:var(--card);padding:8px;margin:20px 0}
.engine-example .res-hero{border-radius:10px}
.snap-note{display:block;font-size:12.5px;color:var(--green);margin-top:8px;font-weight:600}
.pill.pend{background:var(--amber-bg);color:var(--amber-ink)}
.field-check{display:flex;gap:10px;align-items:flex-start;margin-top:16px;font-size:14px;font-weight:600;color:var(--ink-2)}
.field-check input{margin-top:3px;width:17px;height:17px}
.field-check .field-help{display:block;font-weight:400}
.guide-body{max-width:100%}
.guide-body table{border-collapse:collapse;width:100%;font-size:14.5px;margin:14px 0}
.guide-body th,.guide-body td{border:1px solid var(--line);padding:9px 12px;text-align:left}
.guide-body th{background:var(--tint);font-weight:700}
.guide-body .tbl-scroll{overflow-x:auto}
.example .row.total .v{font-weight:800;color:#9FE8C9}
.const li b{color:var(--green-deep)}
.ad-slot{min-height:0}
.seg button{min-height:38px}
/* 响应式（设计稿为 1440px 桌面基准，移动端为实现补充） */
@media (max-width:1000px){
  .calc{grid-template-columns:1fr}
  .prose{grid-template-columns:1fr}
  .grid8{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:1fr}
  .band-grid{grid-template-columns:1fr;gap:36px;padding:48px 0 56px}
  h1.display{font-size:38px}
  .res-big{font-size:48px}
  .ft{grid-template-columns:1fr 1fr}
}
@media (max-width:640px){
  .grid8{grid-template-columns:1fr}
  .est-grid{grid-template-columns:1fr}
  .split{grid-template-columns:1fr}
  .blk+.blk{border-left:0;border-top:1px solid var(--line)}
  .seg{grid-template-columns:repeat(2,1fr)}
  .mecards{grid-template-columns:1fr}
  .big{font-size:42px}
  .top-cta{display:none}
  .top-in{gap:16px}
}
/* 打印 */
@media print{
  header.top,footer,.snap,.crumbs,.faq,.rel,.ad-slot{display:none!important}
  body{background:#fff}
  .calc,.prose{grid-template-columns:1fr}
}

/* 移动端导航防溢出（设计稿为桌面基准，此为实现补充） */
@media (max-width:640px){
  nav.main{display:none}
}
.ft-bar{flex-wrap:wrap}

.prose .body p,.prose .body li,.prose .body td,.prose .body th,.guide-body p,.guide-body li,.guide-body td{overflow-wrap:anywhere}