@font-face{font-family:"Inter";font-style:normal;font-weight:400;font-display:swap;
  src:url("/assets/fonts/inter-400.woff2") format("woff2")}
@font-face{font-family:"Inter";font-style:normal;font-weight:600;font-display:swap;
  src:url("/assets/fonts/inter-600.woff2") format("woff2")}
@font-face{font-family:"Inter";font-style:normal;font-weight:700;font-display:swap;
  src:url("/assets/fonts/inter-700.woff2") format("woff2")}
/* ===== Reset & tokens ===== */
*,*::before,*::after{box-sizing:border-box}
:root{
  --bg:#f7f8fa; --card:#fff; --ink:#12161c; --ink-2:#4a5261; --ink-3:#7b8494;
  --line:#e3e7ee; --brand:#0f5c8c; --brand-2:#0b7ea8; --accent:#e8f3f9;
  --ok:#0a7d4f; --warn:#a8570a; --radius:10px;
  --shadow:0 1px 2px rgba(16,24,40,.05),0 1px 3px rgba(16,24,40,.06);
  --font:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;
}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font);
  font-size:16px;line-height:28px;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:860px;margin:0 auto;padding:0 18px}

/* ===== Header ===== */
.site-header{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;height:56px}
.logo{font-weight:700;font-size:17px;color:var(--ink);letter-spacing:-.01em}
.logo span{color:var(--brand)}
.nav a{font-size:14px;line-height:20px;color:var(--ink-2);margin-left:16px}
@media(max-width:600px){.nav{display:none}}

/* ===== Hero ===== */
.hero{padding:32px 0 8px}
.hero h1{font-size:clamp(24px,4.4vw,32px);line-height:40px;margin:0 0 12px;letter-spacing:-.02em}
.hero p{color:var(--ink-2);font-size:16px;line-height:28px;margin:0 0 8px;max-width:64ch}

/* ===== Card / calculator ===== */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:20px;margin:18px 0}
.card h2{margin:0 0 4px;font-size:18px;letter-spacing:-.01em}
.card .sub{color:var(--ink-3);font-size:13px;line-height:20px;margin:0 0 16px}

.field{margin-bottom:14px}
.field label{display:block;font-size:13px;line-height:20px;font-weight:600;color:var(--ink-2);margin-bottom:8px}
.field input,.field select{width:100%;padding:10px 12px;font-size:15px;border:1px solid var(--line);
  border-radius:8px;background:#fff;color:var(--ink);font-family:inherit}
.field input:focus,.field select:focus{outline:2px solid var(--accent);border-color:var(--brand-2)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media(max-width:560px){.grid2{grid-template-columns:1fr}}
.hint{font-size:12px;line-height:16px;color:var(--ink-3);margin-top:4px}

button.btn{width:100%;padding:12px;font-size:15px;font-weight:600;color:#fff;
  background:var(--brand);border:0;border-radius:8px;cursor:pointer;font-family:inherit}
button.btn:hover{background:var(--brand-2)}
button.btn.ghost{background:#fff;color:var(--brand);border:1px solid var(--line)}

/* ===== Result ===== */
.result{margin-top:16px;padding:16px;background:var(--accent);border-radius:8px;display:none}
.result.on{display:block}
.result .big{font-size:clamp(26px,6vw,34px);font-weight:700;color:var(--brand);
  letter-spacing:-.02em;line-height:1.15}
.result .big small{font-size:14px;font-weight:500;color:var(--ink-2);display:block;margin-bottom:2px}
.breakdown{margin-top:12px;border-top:1px solid #cfe4ef;padding-top:10px}
.breakdown div{display:flex;justify-content:space-between;font-size:14px;line-height:20px;padding:4px 0;color:var(--ink-2)}
.breakdown div b{color:var(--ink);font-variant-numeric:tabular-nums}
.note{font-size:12px;color:var(--ink-3);margin-top:12px;line-height:16px}

/* ===== Content ===== */
article.prose{margin:26px 0 40px}
article.prose h2{font-size:20px;margin:30px 0 10px;letter-spacing:-.01em}
article.prose h3{font-size:16px;margin:22px 0 8px}
article.prose p{color:var(--ink-2);margin:0 0 13px}
article.prose ul,article.prose ol{color:var(--ink-2);padding-left:22px;margin:0 0 14px}
article.prose li{margin-bottom:6px}
article.prose table{width:100%;border-collapse:collapse;font-size:14px;margin:14px 0}
article.prose th,article.prose td{border:1px solid var(--line);padding:8px 10px;text-align:left}
article.prose th{background:#f0f3f7;font-weight:600}
article.prose td{font-variant-numeric:tabular-nums}

/* ===== FAQ ===== */
.faq{margin:26px 0}
.faq details{background:#fff;border:1px solid var(--line);border-radius:8px;
  padding:12px 16px;margin-bottom:8px}
.faq summary{cursor:pointer;font-weight:600;font-size:15px;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"+";color:var(--brand);font-weight:700;margin-right:8px}
.faq details[open] summary::before{content:"−"}
.faq p{margin:10px 0 2px;color:var(--ink-2);font-size:14px}

/* ===== Tool list ===== */
.tools{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:10px;margin:18px 0}
.tools a{display:block;background:#fff;border:1px solid var(--line);border-radius:8px;
  padding:13px 14px;color:var(--ink);font-size:14px;font-weight:500;box-shadow:var(--shadow)}
.tools a:hover{border-color:var(--brand-2);text-decoration:none}
.tools a small{display:block;color:var(--ink-3);font-weight:400;font-size:12px;margin-top:2px}

/* ===== Footer ===== */
.site-footer{border-top:1px solid var(--line);background:#fff;margin-top:44px;padding:22px 0}
.site-footer .wrap{display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between;
  font-size:13px;color:var(--ink-3)}
.site-footer a{color:var(--ink-3)}

/* brand logo */
.logo{display:inline-flex;align-items:center;gap:8px}.logo__mark{width:26px;height:26px;flex:0 0 26px;display:block}