:root{
  /* Blanco y negro, igual que la tarjeta y la Página de Facebook */
  --bg:#ffffff; --surface:#ffffff; --ink:#111111; --muted:#555555; --line:#e2e2e2;
  --brand:#111111; --brand-ink:#ffffff; --accent:#111111; --accent-ink:#ffffff; --soft:#f4f4f4; --warn:#111111; --warn-bg:#f4f4f4;
  --radius:14px; --maxw:1080px;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#0e0e0e; --surface:#161616; --ink:#f2f2f2; --muted:#a6a6a6; --line:#2a2a2a;
    --brand:#f2f2f2; --brand-ink:#0e0e0e; --accent:#f2f2f2; --accent-ink:#0e0e0e; --soft:#1b1b1b; --warn:#f2f2f2; --warn-bg:#1b1b1b;
  }
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 Inter,system-ui,-apple-system,Segoe UI,Roboto,sans-serif;-webkit-font-smoothing:antialiased}
h1,h2,h3{font-family:"Source Serif 4",Georgia,serif;line-height:1.2;margin:0 0 .5em}
h1{font-size:clamp(2rem,5vw,3.1rem)}
h2{font-size:clamp(1.5rem,3.4vw,2.1rem)}
h3{font-size:1.2rem}
p{margin:0 0 1em}
a{color:var(--brand)}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 16px}
section{padding:64px 0}
.eyebrow{font-size:.8rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:600;margin-bottom:.6em}

/* header */
header{position:sticky;top:0;z-index:10;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
header .wrap{display:flex;align-items:center;justify-content:space-between;height:64px;gap:12px}
.logo{font-family:"Source Serif 4",Georgia,serif;font-weight:700;font-size:1.2rem;color:var(--ink);text-decoration:none;display:flex;align-items:center;gap:10px}
.logo svg{width:30px;height:30px;flex:none}
.warn{border-left:3px solid var(--ink)}
.logo small{display:block;font-family:Inter,sans-serif;font-weight:500;font-size:.72rem;color:var(--muted);letter-spacing:.04em}
nav a{color:var(--muted);text-decoration:none;margin-left:20px;font-size:.92rem}
nav a:hover{color:var(--ink)}
@media (max-width:720px){nav .hide-m{display:none}}

.btn{display:inline-flex;align-items:center;gap:8px;background:var(--accent);color:var(--accent-ink);text-decoration:none;font-weight:600;padding:14px 22px;border-radius:999px;border:0;cursor:pointer;font-size:1rem}
.btn:hover{filter:brightness(1.06)}
.btn.sm{padding:9px 16px;font-size:.9rem}
.btn.ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.btn svg{width:18px;height:18px}

/* hero */
.hero{padding:72px 0 56px}
.hero p.lead{font-size:1.2rem;color:var(--muted);max-width:640px}
.hero .ctas{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.trust{display:flex;flex-wrap:wrap;gap:10px 24px;margin-top:32px;color:var(--muted);font-size:.92rem;padding:0;list-style:none}
.trust li::before{content:"✓";color:var(--accent);font-weight:700;margin-right:8px}

/* cards */
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
@media (max-width:860px){.grid3{grid-template-columns:1fr}}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px}
.card .q{font-weight:600;color:var(--brand);margin-bottom:.4em}
.card p{color:var(--muted);margin:0}

/* steps */
.steps{counter-reset:s;display:grid;grid-template-columns:repeat(4,1fr);gap:18px;list-style:none;padding:0;margin:0}
@media (max-width:860px){.steps{grid-template-columns:1fr 1fr}}
@media (max-width:520px){.steps{grid-template-columns:1fr}}
.steps li{counter-increment:s;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:22px}
.steps li::before{content:counter(s);display:inline-grid;place-items:center;width:32px;height:32px;border-radius:50%;background:var(--soft);color:var(--brand);font-weight:700;margin-bottom:10px}
.steps b{display:block;margin-bottom:4px}
.steps span{color:var(--muted);font-size:.95rem}
.band{background:var(--soft)}

/* calculator */
.calc{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:start}
@media (max-width:860px){.calc{grid-template-columns:1fr}}
.calc form{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px;display:grid;gap:16px}
label{font-weight:600;font-size:.95rem;display:block;margin-bottom:6px}
label small{display:block;font-weight:400;color:var(--muted)}
input{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--ink);font:inherit}
input:focus{outline:2px solid var(--brand);outline-offset:1px}
.result{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px}
.result table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums}
.result td{padding:8px 0;border-bottom:1px solid var(--line)}
.result td:last-child{text-align:right;white-space:nowrap}
.result tr.total td{font-weight:700;font-size:1.15rem;border-bottom:0;padding-top:14px}
.note{background:var(--warn-bg);color:var(--warn);border-radius:10px;padding:12px 14px;font-size:.9rem;margin-top:16px}
.empty{color:var(--muted)}

/* faq */
details{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:0 20px;margin-bottom:10px}
summary{cursor:pointer;font-weight:600;padding:16px 0;list-style:none}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";float:right;color:var(--muted);font-weight:400}
details[open] summary::after{content:"–"}
details p{color:var(--muted)}

/* cta final + footer */
.final{text-align:center}
.final p{color:var(--muted);max-width:560px;margin:0 auto 24px}
footer{border-top:1px solid var(--line);padding:32px 0;color:var(--muted);font-size:.85rem}
footer .wrap{display:grid;gap:8px}

/* floating whatsapp (mobile) */
.fab{position:fixed;right:16px;bottom:16px;z-index:20;box-shadow:0 6px 20px rgba(0,0,0,.18)}
@media (min-width:861px){.fab{display:none}}
@media (max-width:860px){body{padding-bottom:84px}}

/* ===== artículos / guías ===== */
.article{max-width:760px;margin:0 auto;padding:48px 16px 24px}
.article .crumbs{font-size:.85rem;color:var(--muted);margin-bottom:18px}
.article .crumbs a{color:var(--muted)}
.article h1{font-size:clamp(1.8rem,4.4vw,2.6rem)}
.article h2{font-size:1.45rem;margin-top:1.8em}
.article p,.article li{font-size:1.05rem}
.article ul,.article ol{padding-left:1.3em;margin:0 0 1em}
.article li{margin-bottom:.4em}
.article .meta{color:var(--muted);font-size:.9rem;margin-bottom:28px}
.callout{background:var(--soft);border-radius:var(--radius);padding:20px 22px;margin:28px 0}
.callout p:last-child{margin:0}
.warn{background:var(--warn-bg);color:var(--warn);border-radius:10px;padding:14px 16px;font-size:.95rem;margin:24px 0}
.guides{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:28px}
@media (max-width:860px){.guides{grid-template-columns:1fr}}
.guides a{display:block;text-decoration:none;color:inherit}
.guides a:hover .card{border-color:var(--brand)}
.guides .card h3{color:var(--ink)}
.guides .more{color:var(--brand);font-weight:600;font-size:.92rem;margin-top:10px;display:block}