:root{--bg:#f7f8fb;--card:#fff;--accent:#2563eb;--muted:#6b7280}body{font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,Arial;background:var(--bg);margin:0;color:#111}.app{max-width:900px;margin:36px auto;padding:20px}header h1{margin:.2rem 0}.calculator{display:grid;grid-template-columns:1fr 1fr;gap:20px}.inputs,.outputs{background:var(--card);padding:18px;border-radius:8px;box-shadow:0 6px 18px #0f172a0f}.inputs label,.outputs .output-row{display:block;margin-bottom:10px}label input{width:100%;padding:8px;margin-top:6px;border:1px solid #e6eef8;border-radius:6px}details summary{cursor:pointer;margin:8px 0;padding:6px}.output-row{font-size:.95rem}.output-row.total{font-size:1.05rem;margin-top:8px}.note{color:var(--muted);font-size:.85rem}footer{margin-top:16px;text-align:center;color:var(--muted)}@media(max-width:800px){.calculator{grid-template-columns:1fr}}