*{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#ffffff; --surface:#f6f8fb; --surface2:#eef2f7; --border:#e2e7ef;
  --txt:#161a22; --muted:#5b6472; --accent:#2f6bff; --accent2:#0f9d58;
  --warn:#b45309; --radius:12px; --maxw:1120px;
}
body{font-family:-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--txt);background:var(--bg);line-height:1.65;font-size:15px;display:flex;flex-direction:column;min-height:100vh}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 18px}
img{max-width:100%}

/* Header */
header.site{position:sticky;top:0;background:rgba(255,255,255,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--border);z-index:20}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:62px}
.logo{display:flex;align-items:center;gap:8px;font-weight:800;font-size:19px;color:var(--txt);letter-spacing:-.3px}
.logo:hover{text-decoration:none}
.logo-icon{display:flex;align-items:center;justify-content:center;width:32px;height:32px;background:linear-gradient(135deg,var(--accent),#0f9d58);border-radius:9px;color:#fff;font-size:18px;flex-shrink:0}
.logo .brand-accent{color:var(--accent)}
nav.top{display:flex;align-items:center;gap:6px}
nav.top a{margin-left:14px;color:var(--muted);font-size:14px;font-weight:500}
nav.top a:hover{color:var(--accent)}
.lang-toggle{margin-right:8px;border:1px solid var(--border);background:var(--surface);color:var(--txt);
  font-size:13.5px;font-weight:600;border-radius:999px;padding:6px 14px;cursor:pointer;transition:.15s}
.lang-toggle:hover{border-color:var(--accent);color:var(--accent)}

/* Hero + intro */
.hero{background:linear-gradient(180deg,#eef4ff 0%,#ffffff 100%);border-bottom:1px solid var(--border);padding:54px 0 40px}
.hero h1{font-size:34px;line-height:1.25;letter-spacing:-.5px;margin-bottom:14px}
.hero p{font-size:17px;color:var(--muted);max-width:640px}
.badge{display:inline-block;background:#e7f0ff;color:var(--accent);font-size:13px;font-weight:600;padding:5px 12px;border-radius:999px;margin-bottom:18px}
.intro{padding:22px 0 6px}
.intro p{max-width:820px;color:var(--muted);font-size:15.5px}

/* Sections */
section.block{padding:40px 0}
.section-title{font-size:13px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin-bottom:18px}

/* Icon cards (homepage) */
.grid.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:16px}
.card{display:flex;flex-direction:column;align-items:flex-start;text-align:left;background:var(--surface);
  border:1px solid var(--border);border-radius:var(--radius);padding:18px;transition:.15s;
  font-family:inherit;color:var(--txt)}
.card:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:0 6px 18px rgba(47,107,255,.10);text-decoration:none}
.card .ic{font-size:30px;line-height:1;margin-bottom:10px}
.card h3{font-size:16px;margin-bottom:6px;color:var(--txt)}
.card p{font-size:13.5px;color:var(--muted)}

/* Tool page layout */
.tool-header{padding:34px 0 0}
.tool-header h1{font-size:30px;letter-spacing:-.4px;margin-bottom:10px}
.tool-header .lede{color:var(--muted);font-size:16px;margin-bottom:22px;max-width:760px}
.tool-layout{display:grid;grid-template-columns:1fr 320px;gap:30px;padding:0 0 50px;align-items:start}
.sidebar{position:sticky;top:84px;align-self:start}
.ad-label{font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:#a3acbb;margin-bottom:8px}

/* Calculator UI */
.calc{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;max-width:560px}
.field{margin-bottom:14px}
.field label{display:block;font-size:13px;font-weight:600;margin-bottom:6px;color:#2a3140}
.field input[type=number],.field input[type=date],.field select{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:9px;font-size:14px;background:#fff;color:var(--txt);font-family:inherit}
.btn{display:inline-block;background:var(--accent);color:#fff;border:none;border-radius:9px;padding:12px 22px;font-size:15px;font-weight:600;cursor:pointer;font-family:inherit;margin-top:4px}
.btn:hover{background:#2257e0}
.result{margin-top:20px}
.line{display:flex;justify-content:space-between;align-items:baseline;gap:14px;padding:9px 0;border-bottom:1px solid var(--border);font-size:15px}
.line span{color:var(--muted)}
.line b{font-size:16px;font-variant-numeric:tabular-nums}
.line.total{border-bottom:none;padding-top:14px;margin-top:4px}
.line.total span{color:var(--txt);font-weight:700}
.line.total b{font-size:20px;color:var(--accent);font-weight:800}
.note{font-size:12.5px;color:var(--muted);margin-top:12px}
.formula{display:block;background:var(--surface2);border:1px solid var(--border);border-radius:9px;padding:12px 14px;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:14px;margin:10px 0;overflow-x:auto}

/* Content layer (how it works + guide + faq + related) */
.content{border-top:1px solid var(--border);margin-top:30px;padding-top:26px}
.content h2{font-size:21px;margin:22px 0 10px}
.content p,.content li{color:#3a4250;font-size:15px}
.content ul{margin:8px 0 8px 22px}
.article h3{font-size:17px;margin:18px 0 8px;color:var(--txt)}
.tax-table{width:100%;border-collapse:collapse;margin:12px 0;font-size:14px}
.tax-table th,.tax-table td{border:1px solid var(--border);padding:8px 10px;text-align:left}
.tax-table th{background:var(--surface);font-weight:700}
.tax-table tbody tr:nth-child(even){background:var(--surface)}
.disclaimer{background:#fffaf0;border-left:4px solid var(--warn);border-radius:0 10px 10px 0;padding:14px 16px;
  margin:18px 0;font-size:13.5px;color:#7a5a2a}
.faq{margin-top:14px}
.faq-item{border:1px solid var(--border);border-radius:10px;padding:14px 16px;margin-bottom:10px;background:var(--surface)}
.faq-item .q{font-weight:700;color:var(--txt);margin-bottom:4px}
.faq-item .a{color:var(--muted);font-size:14.5px}
.related{display:flex;flex-wrap:wrap;gap:10px;margin-top:10px}
.rel-card{display:inline-flex;align-items:center;gap:8px;background:var(--surface2);border:1px solid var(--border);
  border-radius:10px;padding:9px 14px;font-size:14px;color:#2a3140;font-weight:500}
.rel-card:hover{border-color:var(--accent);color:var(--accent);text-decoration:none}
.rel-card .ic{font-size:18px}

/* Legal / prose pages */
.prose{max-width:760px;padding:40px 0 60px}
.prose h1{font-size:30px;margin-bottom:16px}
.prose h2{font-size:20px;margin:26px 0 10px}
.prose p,.prose li{color:#3a4250;font-size:15.5px;margin-bottom:10px}
.prose ul{margin-left:22px}

/* Footer */
footer.site{border-top:1px solid var(--border);background:var(--surface);padding:34px 0;margin-top:auto;color:var(--muted);font-size:13.5px}
.footer-inner{display:flex;flex-wrap:wrap;justify-content:space-between;gap:18px}
.footer-inner a{color:var(--muted);margin-right:16px}
.footer-inner a:hover{color:var(--accent)}
.disclaim{font-size:12px;color:#9aa3b2;margin-top:14px;max-width:720px}

@media(max-width:860px){
  .tool-layout{grid-template-columns:1fr}
  .sidebar{position:static}
  .ad-box{min-height:90px}
  .ad-banner,.ad-native,.ad-result{width:100%;height:auto;min-height:90px}
  .ad-sidebar{width:100%;height:auto;min-height:250px}
  .hero h1{font-size:27px}
}

/* Author / review byline (YMYL signals) */
.byline{border-top:1px solid var(--border);border-bottom:1px solid var(--border);background:var(--surface);padding:16px 18px;margin:auto 0 10px;border-radius:var(--radius);font-size:13.5px;color:var(--muted);text-align:center}
.byline p{margin-bottom:6px}
.byline p:last-child{margin-bottom:0}
.byline strong{color:var(--txt)}
.byline-note{font-size:12.5px;color:#9aa3b2}
/* When a byline sits directly above the footer, push the pair to the bottom
   on short pages (footer's own auto margin is cancelled so there is no gap). */
.byline + footer.site{margin-top:0}

/* Result disclaimer note under each calculator output */
.result-note{font-size:12px;color:#9aa3b2;margin-top:10px;text-align:right}

/* Ad placeholders (filled with real AdSense units after approval) */
.ad-label{font-size:11px;letter-spacing:.04em;text-transform:uppercase;color:#9aa3b2;margin:18px 0 6px}
.ad-box{border:1px dashed #c4ccd8;background:#f3f6fa;border-radius:10px;color:#8a93a3;
  display:flex;align-items:center;justify-content:center;text-align:center;
  font-size:13px;padding:14px;min-height:90px}
/* Banner ad section: constrained to content width so it aligns with body text */
.ad-section{width:100%}
.ad-section-banner{max-width:var(--maxw);margin:18px auto 0;padding:0 18px}
.ad-section-banner .ad-label{font-size:10px;line-height:1;margin:0 0 4px}
/* Banner ads: left-aligned horizontal units at content width (leaderboard-style) */
.ad-banner{width:100%;height:90px;margin:0;padding:0;
  border:1px dashed #c4ccd8;background:#f3f6fa;border-radius:10px;color:#8a93a3;
  display:flex;align-items:center;justify-content:flex-start;text-align:left;font-size:13px}
/* Sidebar ads: square units */
.ad-sidebar{width:300px;height:300px;margin:0}
/* In-content native ads: horizontal units under FAQ/results */
.ad-native{width:100%;max-width:728px;height:90px;margin:0}
.ad-result{width:100%;max-width:728px;height:90px;margin:16px 0 0}

/* Visible dataset-version label on every calculator (anti-stale-data safeguard) */
.data-version{display:inline-block;font-size:12px;color:#5b6573;background:#eef2f7;
  border:1px solid #dde4ec;border-radius:999px;padding:4px 12px;margin:0 0 4px}

/* Blog (SEO articles) */
.blog-index{padding:40px 0 60px}
.blog-index h1{font-size:30px;margin-bottom:8px}
.blog-index .lede{color:var(--muted);font-size:16px;margin-bottom:28px;max-width:720px}
.blog-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px}
.blog-card{display:flex;flex-direction:column;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;transition:.15s;color:var(--txt)}
.blog-card:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:0 6px 18px rgba(47,107,255,.10);text-decoration:none}
.blog-card h3{font-size:17px;margin:10px 0 8px;color:var(--txt)}
.blog-card p{font-size:13.5px;color:var(--muted);flex:1}
.blog-cat{display:inline-block;align-self:flex-start;background:#e7f0ff;color:var(--accent);font-size:11px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;padding:4px 10px;border-radius:999px}
.blog-date{font-size:12px;color:var(--muted);margin-top:12px}
.blog-layout{display:flex;gap:32px;align-items:stretch;padding:30px 0 60px}
.blog-post{flex:1;min-width:0;padding:0}
.blog-post .blog-meta{display:flex;align-items:center;gap:12px;margin-bottom:6px}
.blog-post .blog-cat{margin:0}
.blog-post h1{font-size:30px;letter-spacing:-.4px;margin-bottom:22px;line-height:1.25}
.blog-post .prose{max-width:760px;padding:0 0 40px}
.blog-sidebar{width:360px;flex-shrink:0;position:relative}
.blog-sidebar-inner{position:sticky;top:82px}
.blog-sidebar .calc-embed-wrap{margin:0;max-width:100%;width:100%}
.blog-sidebar .calc-embed{height:560px}
.calc-embed-wrap{margin:8px 0 26px;max-width:560px;width:100%;background:transparent;border:none;overflow:visible}
.calc-embed-wrap .ad-label{margin:0 0 10px;font-size:12px}
.calc-embed{width:100%;height:640px;border:0;display:block;border-radius:var(--radius);overflow:hidden}
.data{width:100%;border-collapse:collapse;margin:14px 0;font-size:14px}
.data th,.data td{border:1px solid var(--border);padding:9px 12px;text-align:left}
.data th{background:var(--surface);font-weight:700}
.data tbody tr:nth-child(even){background:var(--surface)}
.data td:not(:first-child){font-variant-numeric:tabular-nums}
@media(max-width:960px){
  .blog-layout{flex-direction:column}
  .blog-sidebar{width:100%;order:2}
  .blog-sidebar-inner{position:static}
  .blog-sidebar .calc-embed{height:640px}
}
@media(max-width:860px){.calc-embed{height:640px}}