:root{
  --bg:#0f1420; --card:#171f30; --ink:#e8edf6; --muted:#9aa7bd;
  --brand:#3ba7ff; --brand2:#25d366; --line:#243049; --danger:#ff5d5d;
}
@media (prefers-color-scheme: light){
  :root{ --bg:#f5f7fb; --card:#ffffff; --ink:#152036; --muted:#5a6577;
         --brand:#0a74d1; --brand2:#128c3e; --line:#e2e8f2; }
}
*{box-sizing:border-box}
body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  background:var(--bg);color:var(--ink);line-height:1.65}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
main{max-width:900px;margin:0 auto;padding:20px 18px 60px}
h1{font-size:1.9rem;line-height:1.2;margin:.2em 0 .4em}
h2{font-size:1.35rem;margin:1.6em 0 .5em}
h3{margin:.2em 0}
.lead{color:var(--muted);font-size:1.08rem}
code{background:var(--line);padding:2px 7px;border-radius:6px;font-size:.95em}

/* header / footer */
.site-header{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;
  gap:10px;padding:14px 18px;background:var(--card);border-bottom:1px solid var(--line);
  position:sticky;top:0;z-index:10}
.logo{font-weight:800;font-size:1.15rem;color:var(--ink)}
.site-header nav a{margin-left:16px;color:var(--muted);font-weight:600}
.site-footer{max-width:900px;margin:0 auto;padding:30px 18px;color:var(--muted);
  border-top:1px solid var(--line);font-size:.9rem;text-align:center}
.disclaimer{font-size:.82rem;opacity:.8}

/* hero */
.hero{text-align:center;padding:36px 10px 10px}
.hero h1{font-size:2.2rem}
.btn{display:inline-block;margin:8px 6px;padding:12px 22px;border-radius:12px;
  background:var(--brand);color:#fff;font-weight:700}
.btn.ghost{background:transparent;border:1px solid var(--line);color:var(--ink)}
.btn:hover{text-decoration:none;opacity:.92}

/* grid de tarjetas */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:14px}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px;
  display:flex;flex-direction:column;gap:6px;transition:.15s}
.card:hover{border-color:var(--brand);transform:translateY(-2px);text-decoration:none}
.card p{color:var(--muted);font-size:.9rem;margin:.2em 0 auto}
.card .go{color:var(--brand);font-weight:700;font-size:.9rem}

/* botón descarga */
.download{display:inline-block;background:var(--brand2);color:#fff;font-weight:800;
  padding:15px 26px;border-radius:12px;font-size:1.1rem;margin:6px 0}
.download:hover{text-decoration:none;opacity:.92}
.note{color:var(--muted)}

/* pasos / faq */
.steps{padding-left:1.2em}
.steps li{margin:.35em 0}
.crumbs{color:var(--muted);font-size:.85rem;margin-bottom:6px}
.faq details{background:var(--card);border:1px solid var(--line);border-radius:10px;
  padding:10px 14px;margin:8px 0}
.faq summary{cursor:pointer;font-weight:600}
.cta{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:12px 16px}
.guide{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin-top:10px}

/* anuncios */
.ad{min-height:90px;display:flex;align-items:center;justify-content:center;
  margin:22px 0;position:relative;padding-top:16px}
.ad-inner{max-width:100%;overflow-x:auto;justify-content:center}
.ad-label{position:absolute;top:0;left:4px;font-size:.62rem;color:var(--muted);text-transform:uppercase;letter-spacing:.5px}
/* Responsive: banner 728x90 en escritorio, 320x50 en móvil */
.ad-desktop{display:flex}
.ad-mobile{display:none}
@media(max-width:760px){
  .ad-desktop{display:none}
  .ad-mobile{display:flex}
}
@media(max-width:520px){.hero h1{font-size:1.7rem}h1{font-size:1.6rem}}