:root{--ink:#1a2332;--muted:#5b6b7f;--bg:#fff;--soft:#f4f7fb;--line:#e2e8f0;--accent:#0d6efd;--accent2:#0a7d4f}
*{box-sizing:border-box}
body{margin:0;font:16px/1.65 system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--ink);background:var(--bg)}
header,footer{padding:1rem clamp(1rem,4vw,2rem);border-bottom:1px solid var(--line);display:flex;flex-wrap:wrap;gap:1rem;align-items:center;justify-content:space-between}
footer{border:0;border-top:1px solid var(--line);display:block;color:var(--muted);font-size:.9rem;margin-top:3rem}
.brand{font-weight:800;font-size:1.15rem;color:var(--ink);text-decoration:none}
nav a{color:var(--muted);text-decoration:none;margin-left:1rem;font-size:.95rem}
nav a:hover{color:var(--accent)}
main{max-width:760px;margin:0 auto;padding:0 clamp(1rem,4vw,2rem)}
h1{font-size:clamp(1.6rem,4vw,2.3rem);line-height:1.2;margin:2rem 0 1rem}
h2{margin:2.2rem 0 .6rem;font-size:1.4rem}
h3{margin:1.6rem 0 .4rem}
a{color:var(--accent)}
.lead{font-size:1.15rem;color:var(--muted)}
.tool{background:var(--soft);border:1px solid var(--line);border-radius:14px;padding:1.25rem;margin:1.5rem 0}
.tool label{display:block;font-weight:600;margin:.7rem 0 .25rem;font-size:.95rem}
.tool input,.tool select{width:100%;padding:.6rem .7rem;border:1px solid var(--line);border-radius:8px;font:inherit}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:1rem}
.result{margin-top:1.2rem;padding:1rem;background:#fff;border:1px solid var(--line);border-radius:10px}
.big{font-size:2rem;font-weight:800;color:var(--accent2)}
table{border-collapse:collapse;width:100%;margin:1rem 0}
th,td{border:1px solid var(--line);padding:.55rem .7rem;text-align:left}
th{background:var(--soft)}
.faq dt{font-weight:700;margin-top:1.1rem}
.faq dd{margin:.3rem 0 0;color:var(--muted)}
.disclaimer{font-size:.8rem}
@media(max-width:520px){.grid{grid-template-columns:1fr}}

/* --- early-payoff supplemental --- */
button#calc{background:#0b6;color:#fff;border:0;padding:.7rem 1.3rem;font-size:1rem;border-radius:6px;cursor:pointer;margin-top:.4rem}
button#calc:hover{background:#0a5}
.headline{font-size:1.1rem;background:#f0fbf6;border-left:4px solid #0b6;padding:.8rem 1rem;border-radius:4px}
.result{margin-top:1rem}
table.cmp,table.info{border-collapse:collapse;width:100%;margin:1rem 0}
table.cmp th,table.cmp td,table.info th,table.info td{border:1px solid #ddd;padding:.5rem .6rem;text-align:left}
table.cmp th,table.info th{background:#f6f7f9}
table.cmp tr.tot td{font-weight:600;border-top:2px solid #bbb}
table.info caption{caption-side:top;text-align:left;font-weight:600;margin-bottom:.4rem}
.hint{color:#667;font-size:.9rem}
details{border:1px solid #e3e3e3;border-radius:6px;padding:.6rem .9rem;margin:.5rem 0}
details summary{font-weight:600;cursor:pointer}
details p{margin:.6rem 0 0}
code{background:#f3f3f5;padding:.1rem .3rem;border-radius:3px}