<!doctype html> <html lang="es"> <head> <meta charset="utf-8" /> <meta name="viewport" content="width=device-width,initial-scale=1" /> <title>Calculadora Dura Fence - Materiales</title> <style> :root{--bg:#f6f8fb;--card:#fff;--accent:#0b6cff;--muted:#6b7280} body{font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial;margin:0;background:var(--bg);color:#111} .wrap{max-width:980px;margin:28px auto;padding:18px} .card{background:var(--card);border-radius:12px;padding:20px;box-shadow:0 8px 30px rgba(10,20,40,0.06)} h1{margin:0 0 8px;font-size:20px} p.lead{margin:0 0 18px;color:var(--muted)} .grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px} label{font-size:13px;color:#222;margin-bottom:6px;display:block} input[type="number"], select, input[type="text"]{width:100%;padding:8px;border:1px solid #e6e9ef;border-radius:8px;font-size:14px} .full{grid-column:1/-1} .row{display:flex;gap:8px} button{background:var(--accent);