:root{--ink:#1f2937;--muted:#6b7280;--line:#e5e7eb;--bg:#ffffff;
--card:#f9fafb;--accent:#0d9488;--accent-dark:#0f766e;--radius:12px}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,
Helvetica,Arial,sans-serif;color:var(--ink);background:var(--bg);line-height:1.6}
.wrap{max-width:720px;margin:0 auto;padding:0 20px}
.site-header{border-bottom:1px solid var(--line);background:#fff}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;
padding-top:14px;padding-bottom:14px}
.brand{font-weight:700;font-size:1.1rem;color:var(--ink);text-decoration:none}
.topnav a{margin-left:18px;color:var(--muted);text-decoration:none;font-size:.95rem}
.topnav a:hover{color:var(--accent-dark)}
main{padding:40px 0 56px}
h1{font-size:1.9rem;line-height:1.25;margin:0 0 8px}
.lede{color:var(--muted);margin:0 0 24px}
.tool-card{background:var(--card);border:1px solid var(--line);border-radius:
var(--radius);padding:28px;margin-bottom:28px}
.field{margin-bottom:16px}
label{display:block;font-size:.85rem;font-weight:600;margin-bottom:6px}
input[type=text],input[type=number]{width:100%;padding:12px;border:1px solid var(--line);
border-radius:8px;font-size:1rem;color:var(--ink)}
select{width:100%;padding:12px;border:1px solid var(--line);border-radius:8px;
font-size:1rem;background:#fff;color:var(--ink)}
.check-label{display:flex;align-items:center;gap:8px;font-size:.95rem;
font-weight:400;margin:0;cursor:pointer}
.check-label input{width:18px;height:18px;accent-color:var(--accent)}
.mode-row{display:flex;gap:12px;margin-bottom:18px}
.mode-btn{flex:1;padding:10px 12px;border:1px solid var(--line);border-radius:8px;
background:#fff;font-size:.92rem;font-weight:600;color:var(--muted);cursor:pointer}
.mode-btn.active{background:var(--accent);border-color:var(--accent);color:#fff}
.wall-row{display:flex;gap:10px;align-items:flex-end;margin-bottom:10px}
.wall-row .field{flex:1;margin-bottom:0}
.wall-row .field label{font-size:.8rem}
.remove-wall{flex:none;padding:10px 12px;border:1px solid var(--line);
border-radius:8px;background:#fff;color:var(--muted);font-size:.9rem;cursor:pointer}
.remove-wall:hover{color:#b91c1c;border-color:#fecaca}
.btn{background:var(--accent);color:#fff;border:0;border-radius:8px;
padding:12px 20px;font-size:1rem;font-weight:600;cursor:pointer;width:100%}
.btn:hover{background:var(--accent-dark)}
.btn.ghost{width:auto;background:#fff;color:var(--accent-dark);
border:1px solid var(--accent);margin-top:12px}
.btn.ghost:hover{background:#f0fdfa}
.error{color:#b91c1c;background:#fef2f2;border:1px solid #fecaca;
border-radius:8px;padding:10px 14px;font-size:.92rem;margin:14px 0 0}
.results{margin-top:18px}
.result-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}
.result{background:#fff;border:1px solid var(--line);border-radius:8px;
padding:12px 14px}
.result .big{font-size:1.5rem;font-weight:700;color:var(--accent-dark);
line-height:1.2}
.result .cap{font-size:.82rem;color:var(--muted)}
.tip{background:#fffbeb;border:1px solid #fde68a;border-radius:8px;
padding:12px 14px;font-size:.92rem;margin-top:12px;color:var(--ink)}
.tip strong{color:#92400e}
.hint{color:var(--muted);font-size:.88rem;margin:12px 0 0}
.answer h2{font-size:1.3rem;margin:32px 0 10px}
.answer p{color:var(--muted)}
.faq h2{font-size:1.3rem;margin:32px 0 10px}
.faq h3{font-size:1.05rem;margin:20px 0 6px}
.faq p{color:var(--muted);margin:0 0 12px}
.site-footer{border-top:1px solid var(--line);padding:24px 0;color:var(--muted);
font-size:.85rem}
.site-footer .wrap{display:flex;flex-wrap:wrap;gap:8px 24px;justify-content:space-between}
.site-footer a{color:var(--muted);text-decoration:none}
.site-footer a:hover{color:var(--accent-dark)}
.prose h1{font-size:1.7rem}
.prose p{color:var(--ink)}
@media(max-width:520px){h1{font-size:1.55rem}.tool-card{padding:20px}
.result-grid{grid-template-columns:1fr 1fr}.mode-row{flex-direction:column;gap:8px}}