/* trenes.gratis — sistema visual basado en DESIGN.md (Tailscale-style warm paper) */
:root{
  --color-ink:#181717; --color-bone:#eeebea; --color-paper:#ffffff;
  --color-graphite:#2e2d2d; --color-charcoal:#575555; --color-ash:#706e6d;
  --color-linen:#f7f5f4; --color-mist:#d5d3d2; --color-signal-red:#d04841;
  --font-inter:'Inter',ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  --radius-lg:8px; --radius-2xl:16px; --radius-3xl:32px; --radius-full:9999px;
  --shadow-sm:rgba(24,23,23,0.02) 0px 4px 8px 0px;
  --shadow-md:rgba(24,23,23,0.16) 0px 4px 16px 0px;
  --maxw:1200px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--color-bone);color:var(--color-ink);
  font-family:var(--font-inter);font-weight:400;font-size:16px;line-height:1.5;
  letter-spacing:-0.1px;-webkit-font-smoothing:antialiased;
}
a{color:var(--color-ink);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;display:block}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.eyebrow{font-size:12px;font-weight:500;letter-spacing:0.05em;text-transform:uppercase;color:var(--color-charcoal)}
.muted{color:var(--color-charcoal)}
.red{color:var(--color-signal-red)}

/* NAV */
.nav{position:sticky;top:0;z-index:50;background:rgba(247,245,244,0.85);backdrop-filter:saturate(180%) blur(8px);border-bottom:1px solid #e4e0df}
.nav-inner{display:flex;align-items:center;gap:16px;height:64px}
.brand{display:flex;align-items:center;gap:9px;font-weight:500;font-size:18px;letter-spacing:-0.3px;flex-shrink:0;white-space:nowrap}
.brand .wordmark{display:inline}
.brand .dot{width:10px;height:10px;border-radius:50%;background:var(--color-signal-red);display:inline-block;flex-shrink:0}
.brand b{font-weight:600}
.nav-links{display:flex;gap:2px;flex-wrap:nowrap;justify-content:center;margin:0 auto;flex:1;min-width:0}
.nav-links a{font-size:14px;font-weight:500;color:var(--color-ink);padding:8px 9px;border-radius:var(--radius-lg);white-space:nowrap}
.nav-links a:hover{background:#eceae9;text-decoration:none}
.nav-cta{background:var(--color-ink);color:#fff;font-size:14px;font-weight:500;padding:9px 16px;border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);flex-shrink:0;white-space:nowrap}
.nav-cta:hover{text-decoration:none;box-shadow:var(--shadow-md)}
.nav-toggle{display:none;background:none;border:0;font-size:22px;cursor:pointer;color:var(--color-ink)}

/* HERO */
.hero{text-align:center;padding:84px 0 64px}
.hero h1{font-weight:300;font-size:clamp(38px,6vw,64px);line-height:1.1;letter-spacing:-1.5px;margin:14px 0 0}
.hero p{max-width:640px;margin:20px auto 0;font-size:18px;color:var(--color-charcoal)}
.hero .cta-row{display:flex;gap:16px;justify-content:center;margin-top:28px;flex-wrap:wrap}
.btn{display:inline-block;background:var(--color-ink);color:#fff;font-weight:500;font-size:14px;padding:11px 20px;border-radius:var(--radius-lg);box-shadow:var(--shadow-sm)}
.btn:hover{text-decoration:none;box-shadow:var(--shadow-md)}
.btn-ghost{background:transparent;color:var(--color-ink);box-shadow:none;border:1px solid #dcd8d7}
.btn-ghost:hover{background:#eceae9}

/* SECTIONS */
section{padding:0 0}
.section-gap{margin-top:88px}
.section-head{text-align:center;max-width:720px;margin:0 auto 40px}
.section-head h2{font-weight:300;font-size:clamp(28px,4vw,48px);letter-spacing:-0.96px;line-height:1.2;margin:8px 0 0}
.section-head p{color:var(--color-charcoal);margin:16px auto 0;max-width:600px}

/* CATEGORY CARD GRID */
.grid{display:grid;gap:20px}
.grid-cats{grid-template-columns:repeat(4,1fr)}
.cat-card{background:var(--color-paper);border-radius:var(--radius-2xl);padding:24px;box-shadow:var(--shadow-sm);display:flex;flex-direction:column;gap:10px;min-height:150px;transition:box-shadow .15s ease}
.cat-card:hover{box-shadow:var(--shadow-md);text-decoration:none}
.cat-card.red{background:var(--color-signal-red);color:#fff}
.cat-card .ico{width:26px;height:26px;color:var(--color-ink)}
.cat-card.red .ico{color:#fff}
.cat-card h3{font-weight:500;font-size:20px;margin:2px 0 0;letter-spacing:-0.2px}
.cat-card p{font-size:14px;color:var(--color-charcoal);margin:0}
.cat-card.red p{color:rgba(255,255,255,0.9)}
.cat-card .count{font-size:12px;font-weight:500;letter-spacing:0.05em;text-transform:uppercase;color:var(--color-ash);margin-top:auto}
.cat-card.red .count{color:rgba(255,255,255,0.85)}

/* ARTICLE CARD GRID */
.grid-arts{grid-template-columns:repeat(3,1fr)}
.art-card{background:var(--color-paper);border-radius:var(--radius-2xl);box-shadow:var(--shadow-sm);overflow:hidden;display:flex;flex-direction:column;transition:box-shadow .15s ease}
.art-card:hover{box-shadow:var(--shadow-md);text-decoration:none}
.art-card .thumb{aspect-ratio:16/9;background:var(--color-linen);position:relative}
.art-card .thumb svg{width:100%;height:100%}
.art-card .body{padding:20px 22px 22px;display:flex;flex-direction:column;gap:8px;flex:1}
.art-card .tag{font-size:12px;font-weight:500;letter-spacing:0.05em;text-transform:uppercase;color:var(--color-signal-red)}
.art-card h3{font-weight:500;font-size:18px;line-height:1.3;margin:0;letter-spacing:-0.2px;color:var(--color-ink)}
.art-card p{font-size:14px;color:var(--color-charcoal);margin:0}
.art-card .meta{margin-top:auto;font-size:12px;color:var(--color-ash);padding-top:6px}

/* ARTICLE PAGE */
.article{background:var(--color-paper);border-radius:var(--radius-3xl);box-shadow:var(--shadow-sm);max-width:820px;margin:40px auto 0;padding:48px clamp(24px,5vw,64px)}
.breadcrumb{font-size:13px;color:var(--color-charcoal);margin-bottom:18px}
.breadcrumb a{color:var(--color-charcoal)}
.article h1{font-weight:300;font-size:clamp(30px,4.5vw,48px);line-height:1.15;letter-spacing:-1px;margin:6px 0 14px}
.article .art-meta{font-size:13px;color:var(--color-ash);display:flex;gap:14px;flex-wrap:wrap;border-bottom:1px solid #e4e0df;padding-bottom:20px;margin-bottom:8px}
.article-body{font-size:17px;line-height:1.7}
.article-body h2{font-weight:400;font-size:28px;letter-spacing:-0.5px;margin:36px 0 12px}
.article-body h3{font-weight:500;font-size:21px;margin:28px 0 10px}
.article-body p{margin:0 0 18px}
.article-body ul,.article-body ol{margin:0 0 18px;padding-left:22px}
.article-body li{margin:6px 0}
.article-body a{color:var(--color-signal-red);text-decoration:underline}
.article-body strong{font-weight:600}
.ad-slot{margin:32px auto;max-width:820px;min-height:1px}

/* FOOTER */
.footer{margin-top:96px;border-top:1px solid #e4e0df;background:var(--color-bone);padding:56px 0 40px}
.footer-cols{display:grid;grid-template-columns:1.4fr repeat(3,1fr);gap:32px}
.footer h4{font-size:12px;font-weight:500;letter-spacing:0.05em;text-transform:uppercase;color:var(--color-ink);margin:0 0 14px}
.footer ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:10px}
.footer a{font-size:14px;color:var(--color-charcoal)}
.footer .brand{margin-bottom:12px}
.footer .tagline{font-size:14px;color:var(--color-charcoal);max-width:260px}
.footer-bottom{margin-top:40px;padding-top:20px;border-top:1px solid #e4e0df;font-size:13px;color:var(--color-ash);display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}

/* HUB intro */
.hub-head{padding:64px 0 8px;max-width:760px}
.hub-head .eyebrow{color:var(--color-signal-red)}
.hub-head h1{font-weight:300;font-size:clamp(32px,5vw,56px);letter-spacing:-1.2px;line-height:1.1;margin:12px 0 0}
.hub-head p{color:var(--color-charcoal);font-size:18px;margin:18px 0 0;max-width:640px}
.empty{background:var(--color-paper);border-radius:var(--radius-2xl);box-shadow:var(--shadow-sm);padding:32px;color:var(--color-charcoal);margin-top:32px}

@media(max-width:900px){
  .grid-cats{grid-template-columns:repeat(2,1fr)}
  .grid-arts{grid-template-columns:repeat(2,1fr)}
  .footer-cols{grid-template-columns:1fr 1fr}
  .nav-links{display:none;position:absolute;top:64px;left:0;right:0;background:var(--color-linen);flex-direction:column;justify-content:flex-start;padding:12px 20px;border-bottom:1px solid #e4e0df;gap:2px}
  .nav-links.open{display:flex}
  .nav-links a{padding:12px 8px}
  .nav-toggle{display:block;margin-left:auto}
  .nav-cta{display:none}
}
@media(max-width:640px){
  .grid-arts,.grid-cats{grid-template-columns:1fr}
  .footer-cols{grid-template-columns:1fr 1fr}
  .article{padding:32px 22px}
}