/* Tu Servicio de Gas Educativo — hoja de estilos */
:root{
  --azul-900:#0a2a4a;
  --azul-700:#0b4f8a;
  --azul-500:#1c7ed6;
  --azul-100:#e6f1fb;
  --verde-700:#157a45;
  --verde-500:#22a35a;
  --verde-100:#e5f6ec;
  --amarillo-500:#f5c518;
  --amarillo-300:#ffe27a;
  --amarillo-100:#fff8dc;
  --rojo-600:#c0392b;
  --rojo-100:#fdecea;
  --texto:#1b2733;
  --texto-suave:#4a5b6b;
  --borde:#d7e1ea;
  --fondo:#f7fafc;
  --blanco:#ffffff;
  --radio:14px;
  --sombra:0 6px 24px rgba(10,42,74,.08);
  --ancho:1120px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:84px}
body{
  margin:0;background:var(--fondo);color:var(--texto);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  font-size:17px;line-height:1.65;
}
img,svg{max-width:100%}
a{color:var(--azul-700)}
a:hover{color:var(--verde-700)}
h1,h2,h3,h4{line-height:1.25;color:var(--azul-900);margin:0 0 .6em}
h1{font-size:clamp(1.9rem,4.5vw,3rem)}
h2{font-size:clamp(1.5rem,3.2vw,2.1rem)}
h3{font-size:1.2rem}
p{margin:0 0 1em}
.contenedor{max-width:var(--ancho);margin:0 auto;padding:0 16px}
.saltar{position:absolute;left:-999px;top:0;background:var(--amarillo-500);color:var(--azul-900);padding:8px 14px;z-index:100;font-weight:700}
.saltar:focus{left:8px}

/* Aviso superior */
.aviso-superior{background:var(--azul-900);color:#fff;font-size:.9rem;text-align:center;padding:8px 16px}
.aviso-superior strong{color:var(--amarillo-300)}

/* Encabezado */
.encabezado{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.97);border-bottom:1px solid var(--borde);backdrop-filter:saturate(1.4) blur(6px)}
.encabezado .contenedor{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:68px}
.marca{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--azul-900)}
.marca svg{width:40px;height:40px;flex:none}
.marca-texto{display:flex;flex-direction:column;line-height:1.1}
.marca-texto b{font-size:1.02rem}
.marca-texto small{font-size:.74rem;color:var(--verde-700);font-weight:600;letter-spacing:.02em}
.nav ul{list-style:none;margin:0;padding:0;display:flex;gap:4px;flex-wrap:wrap}
.nav a{display:block;padding:8px 10px;border-radius:8px;text-decoration:none;color:var(--azul-900);font-size:.93rem;font-weight:600}
.nav a:hover,.nav a[aria-current="page"]{background:var(--verde-100);color:var(--verde-700)}
.menu-boton{display:none;background:none;border:1px solid var(--borde);border-radius:8px;padding:8px 10px;font-size:1rem;cursor:pointer;color:var(--azul-900)}
@media (max-width:960px){
  .menu-boton{display:block}
  .nav{display:none;position:absolute;left:0;right:0;top:100%;background:#fff;border-bottom:1px solid var(--borde);box-shadow:var(--sombra)}
  .nav.abierto{display:block}
  .nav ul{flex-direction:column;padding:8px 16px 16px}
}

/* Navegación simple de páginas legales */
.nav-legal ul{list-style:none;margin:0;padding:0;display:flex;gap:4px;flex-wrap:wrap}
.nav-legal a{display:block;padding:8px 10px;border-radius:8px;text-decoration:none;color:var(--azul-900);font-size:.93rem;font-weight:600}
.nav-legal a:hover,.nav-legal a[aria-current="page"]{background:var(--verde-100);color:var(--verde-700)}
@media (max-width:520px){.marca-texto small{display:none}.marca-texto b{font-size:.9rem}}

/* Portada */
.portada{
  background:
    radial-gradient(900px 400px at 85% -10%,rgba(245,197,24,.35),transparent 60%),
    radial-gradient(700px 380px at 0% 110%,rgba(34,163,90,.30),transparent 60%),
    linear-gradient(135deg,var(--azul-900) 0%,var(--azul-700) 55%,#0f6f7a 100%);
  color:#fff;padding:64px 0 72px;
}
.portada .contenedor{display:grid;grid-template-columns:1.3fr .9fr;gap:40px;align-items:center}
.portada h1{color:#fff}
.portada p.lead{font-size:1.15rem;color:#dcebf7;max-width:60ch}
.etiqueta{display:inline-block;background:var(--amarillo-500);color:var(--azul-900);font-weight:700;font-size:.8rem;padding:4px 12px;border-radius:999px;margin-bottom:14px;letter-spacing:.03em;text-transform:uppercase}
.botones{display:flex;gap:12px;flex-wrap:wrap;margin-top:22px}
.boton{display:inline-block;padding:12px 20px;border-radius:10px;font-weight:700;text-decoration:none}
.boton-primario{background:var(--amarillo-500);color:var(--azul-900)}
.boton-primario:hover{background:var(--amarillo-300);color:var(--azul-900)}
.boton-secundario{border:2px solid rgba(255,255,255,.7);color:#fff}
.boton-secundario:hover{background:rgba(255,255,255,.12);color:#fff}
.portada-logo{display:flex;justify-content:center}
.portada-logo svg{width:min(300px,70vw);height:auto;filter:drop-shadow(0 18px 40px rgba(0,0,0,.35))}
@media (max-width:820px){.portada .contenedor{grid-template-columns:1fr}.portada-logo{order:-1}.portada-logo svg{width:160px}}

/* Aviso de independencia */
.independiente{margin-top:-36px;position:relative;z-index:2}
.independiente .caja{background:#fff;border-radius:var(--radio);box-shadow:var(--sombra);border-left:6px solid var(--verde-500);padding:22px 24px;display:grid;grid-template-columns:auto 1fr;gap:16px;align-items:start}
.independiente .icono{width:44px;height:44px;border-radius:50%;background:var(--verde-100);display:grid;place-items:center;color:var(--verde-700);font-weight:800;font-size:1.3rem}
.independiente ul{margin:.4em 0 0;padding-left:1.1em}
@media (max-width:620px){.independiente .caja{grid-template-columns:1fr;padding:18px}.independiente .icono{display:none}}

/* Secciones */
section{padding:64px 0}
section.alterna{background:#fff;border-top:1px solid var(--borde);border-bottom:1px solid var(--borde)}
.intro-seccion{max-width:760px;margin-bottom:32px}
.intro-seccion p{color:var(--texto-suave)}
.sobretitulo{display:block;color:var(--verde-700);font-weight:800;font-size:.8rem;text-transform:uppercase;letter-spacing:.08em;margin-bottom:6px}

.rejilla{display:grid;gap:20px}
.rejilla-2{grid-template-columns:repeat(2,1fr)}
.rejilla-3{grid-template-columns:repeat(3,1fr)}
.rejilla-4{grid-template-columns:repeat(4,1fr)}
@media (max-width:900px){.rejilla-3,.rejilla-4{grid-template-columns:repeat(2,1fr)}}
@media (max-width:620px){.rejilla-2,.rejilla-3,.rejilla-4{grid-template-columns:1fr}}

.tarjeta{background:#fff;border:1px solid var(--borde);border-radius:var(--radio);padding:22px;box-shadow:0 1px 0 rgba(10,42,74,.03)}
.tarjeta h3{margin-bottom:.4em}
.tarjeta p:last-child{margin-bottom:0}
.tarjeta .num{display:inline-grid;place-items:center;width:36px;height:36px;border-radius:10px;background:var(--azul-100);color:var(--azul-700);font-weight:800;margin-bottom:10px}
.tarjeta.verde{border-top:5px solid var(--verde-500)}
.tarjeta.azul{border-top:5px solid var(--azul-500)}
.tarjeta.amarilla{border-top:5px solid var(--amarillo-500)}

/* Cadena de valor */
.cadena{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(5,1fr);gap:14px;counter-reset:paso}
.cadena li{position:relative;background:#fff;border:1px solid var(--borde);border-radius:var(--radio);padding:20px 16px;text-align:center}
.cadena li::before{counter-increment:paso;content:counter(paso);display:grid;place-items:center;width:40px;height:40px;margin:0 auto 10px;border-radius:50%;background:linear-gradient(135deg,var(--verde-500),var(--azul-500));color:#fff;font-weight:800}
.cadena li:not(:last-child)::after{content:"→";position:absolute;right:-13px;top:50%;transform:translateY(-50%);color:var(--verde-700);font-weight:800;font-size:1.2rem}
.cadena h3{font-size:1.02rem}
.cadena p{font-size:.93rem;color:var(--texto-suave);margin:0}
@media (max-width:900px){.cadena{grid-template-columns:1fr}.cadena li:not(:last-child)::after{content:"↓";right:auto;left:50%;top:auto;bottom:-20px;transform:translateX(-50%)}}

/* Tablas */
.tabla-envoltura{overflow-x:auto;border:1px solid var(--borde);border-radius:var(--radio);background:#fff}
table{border-collapse:collapse;width:100%;min-width:560px}
th,td{padding:12px 14px;text-align:left;border-bottom:1px solid var(--borde);vertical-align:top}
thead th{background:var(--azul-900);color:#fff;font-size:.92rem}
tbody tr:nth-child(even){background:#f4f8fb}
tbody tr:last-child td{border-bottom:none}

/* Factura ilustrativa */
.factura{background:#fff;border:2px dashed var(--azul-500);border-radius:var(--radio);padding:22px;position:relative}
.factura::before{content:"EJEMPLO ILUSTRATIVO — NO ES UNA FACTURA REAL";position:absolute;top:-13px;left:18px;background:var(--amarillo-500);color:var(--azul-900);font-size:.72rem;font-weight:800;padding:3px 10px;border-radius:6px;letter-spacing:.04em}
.factura dl{display:grid;grid-template-columns:1fr auto;gap:8px 18px;margin:0}
.factura dt{color:var(--texto-suave)}
.factura dd{margin:0;font-weight:700;text-align:right;font-variant-numeric:tabular-nums}
.factura .total{border-top:2px solid var(--borde);padding-top:8px;color:var(--azul-900)}
.formula{background:var(--azul-100);border-radius:10px;padding:14px 16px;font-weight:700;color:var(--azul-900);text-align:center;margin:14px 0;font-size:1.05rem}

/* Alertas */
.alerta{border-radius:var(--radio);padding:20px 22px;margin:0 0 20px}
.alerta h3{margin-bottom:.4em}
.alerta-roja{background:var(--rojo-100);border-left:6px solid var(--rojo-600)}
.alerta-roja h3{color:var(--rojo-600)}
.alerta-amarilla{background:var(--amarillo-100);border-left:6px solid var(--amarillo-500)}
.alerta-verde{background:var(--verde-100);border-left:6px solid var(--verde-500)}
.alerta-azul{background:var(--azul-100);border-left:6px solid var(--azul-500)}
ol.pasos{padding-left:1.3em;margin:0}
ol.pasos li{margin-bottom:6px}

/* Llamas comparativas */
.llamas{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
.llama-caja{display:flex;gap:16px;align-items:center;background:#fff;border:1px solid var(--borde);border-radius:var(--radio);padding:18px}
.llama-caja svg{width:56px;height:72px;flex:none}
@media (max-width:620px){.llamas{grid-template-columns:1fr}}

/* Listas con check */
.lista-check{list-style:none;padding:0;margin:0}
.lista-check li{position:relative;padding-left:30px;margin-bottom:10px}
.lista-check li::before{content:"✓";position:absolute;left:0;top:0;width:22px;height:22px;border-radius:50%;background:var(--verde-500);color:#fff;display:grid;place-items:center;font-size:.8rem;font-weight:800}
.lista-x li::before{content:"✕";background:var(--rojo-600)}

/* Preguntas frecuentes */
details{background:#fff;border:1px solid var(--borde);border-radius:12px;padding:0 18px;margin-bottom:12px}
details[open]{box-shadow:var(--sombra)}
summary{cursor:pointer;font-weight:700;color:var(--azul-900);padding:16px 0;list-style:none;display:flex;justify-content:space-between;gap:12px}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";font-size:1.4rem;line-height:1;color:var(--verde-700)}
details[open] summary::after{content:"–"}
details > div{padding:0 0 16px;color:var(--texto)}

/* Glosario */
.glosario{display:grid;grid-template-columns:repeat(2,1fr);gap:0 32px;margin:0}
.glosario div{padding:14px 0;border-bottom:1px solid var(--borde)}
.glosario dt{font-weight:800;color:var(--azul-700)}
.glosario dd{margin:4px 0 0;color:var(--texto-suave)}
@media (max-width:720px){.glosario{grid-template-columns:1fr}}

/* Entidades */
.entidad a{font-weight:700;word-break:break-word}

/* Pie de página */
.pie{background:var(--azul-900);color:#c9d9e8;padding:48px 0 24px;font-size:.95rem}
.pie h3{color:#fff;font-size:1.05rem}
.pie a{color:var(--amarillo-300)}
.pie a:hover{color:#fff}
.pie .columnas{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:28px}
.pie ul{list-style:none;padding:0;margin:0}
.pie li{margin-bottom:6px}
.pie .legal{border-top:1px solid rgba(255,255,255,.15);margin-top:32px;padding-top:18px;font-size:.85rem;color:#9fb6cc}
.pie address{font-style:normal}
@media (max-width:820px){.pie .columnas{grid-template-columns:1fr}}

/* Páginas legales */
.pagina-legal{padding:48px 0 64px}
.pagina-legal .documento{background:#fff;border:1px solid var(--borde);border-radius:var(--radio);padding:clamp(20px,4vw,48px);max-width:860px;margin:0 auto;box-shadow:var(--sombra)}
.pagina-legal h2{font-size:1.35rem;margin-top:1.6em;padding-top:.4em;border-top:1px solid var(--borde)}
.pagina-legal h2:first-of-type{border-top:none;margin-top:1em}
.pagina-legal .fecha{color:var(--texto-suave);font-size:.95rem}
.cabecera-legal{background:linear-gradient(135deg,var(--azul-900),var(--azul-700) 60%,#0f6f7a);color:#fff;padding:44px 0}
.cabecera-legal h1{color:#fff;margin:0}
.cabecera-legal p{color:#dcebf7;margin:.4em 0 0}

.volver-arriba{position:fixed;right:16px;bottom:16px;width:46px;height:46px;border-radius:50%;background:var(--verde-500);color:#fff;display:grid;place-items:center;text-decoration:none;font-weight:800;box-shadow:var(--sombra);font-size:1.2rem}
.volver-arriba:hover{background:var(--verde-700);color:#fff}

@media print{.encabezado,.volver-arriba,.aviso-superior{display:none}}