/* TuAula · Plataforma — estilos comunes de las páginas de demostración */
:root {
  --fondo: #0b1430;
  --fondo-2: #121f47;
  --tarjeta: #17275a;
  --borde: rgba(255, 255, 255, 0.10);
  --texto: #f4f6ff;
  --suave: #b8c1e3;
  --coral: #ff6b4a;
  --turquesa: #1fd1b2;
  --amarillo: #ffc93c;
  --violeta: #8b5cf6;
  --cielo: #38bdf8;
  --radio: 18px;
  --ancho: 1180px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--fondo); color: var(--texto);
  font: 17px/1.55 "Nunito", system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
}
img, video { max-width: 100%; display: block; }
a { color: inherit; }
h1, h2, h3 { font-family: "Fredoka", "Nunito", sans-serif; font-weight: 600; line-height: 1.15; margin: 0 0 .4em; }
h1 { font-size: clamp(2.1rem, 5vw, 3.6rem); }
h2 { font-size: clamp(1.6rem, 3.4vw, 2.4rem); }
h3 { font-size: 1.2rem; }
p { margin: 0 0 1em; }
.envoltura { width: min(var(--ancho), 100% - 32px); margin-inline: auto; }

/* Barra superior */
.barra {
  position: sticky; top: 0; z-index: 20;
  background: rgba(11, 20, 48, 0.86); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--borde);
}
.barra .envoltura { display: flex; align-items: center; gap: 20px; min-height: 64px; flex-wrap: wrap; }
.marca { display: flex; align-items: center; gap: 10px; text-decoration: none; font-family: "Fredoka", sans-serif; font-size: 1.35rem; font-weight: 600; }
.marca .emblema { width: 36px; height: 36px; border-radius: 10px; box-shadow: 0 0 0 1px rgba(255,157,56,.35), 0 4px 14px rgba(255,120,30,.25); }
.marca small { font-family: "Nunito", sans-serif; font-weight: 700; color: var(--suave); font-size: .8rem; letter-spacing: .08em; text-transform: uppercase; }
.menu { display: flex; gap: 4px; margin-left: auto; flex-wrap: wrap; }
.menu a { text-decoration: none; padding: 8px 14px; border-radius: 999px; font-weight: 700; font-size: .95rem; color: var(--suave); }
.menu a:hover, .menu a[aria-current="page"] { background: var(--tarjeta); color: var(--texto); }

/* Portadas de sección */
.portada { position: relative; padding: 72px 0 56px; overflow: hidden; isolation: isolate; }
.etiqueta { display: inline-block; padding: 6px 14px; border-radius: 999px; background: rgba(255,255,255,.08); border: 1px solid var(--borde); font-weight: 800; font-size: .8rem; letter-spacing: .08em; text-transform: uppercase; color: var(--amarillo); margin-bottom: 16px; }
.portada p.lead { font-size: 1.2rem; color: var(--suave); max-width: 720px; }
.portada.con-imagen { min-height: 460px; display: flex; align-items: flex-end; }
.portada.con-imagen::before { content: ""; position: absolute; inset: 0; background: var(--img) center/cover no-repeat; z-index: -2; }
.portada.con-imagen::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, rgba(11,20,48,.15) 0%, rgba(11,20,48,.75) 60%, var(--fondo) 100%); z-index: -1; }

section.bloque { padding: 48px 0; }
section.bloque > .envoltura > p.intro { color: var(--suave); max-width: 760px; }

/* Rejillas y tarjetas */
.rejilla { display: grid; gap: 20px; grid-template-columns: repeat(auto-fill, minmax(min(100%, 270px), 1fr)); }
.rejilla.ancha { grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr)); }
.tarjeta {
  background: var(--tarjeta); border: 1px solid var(--borde); border-radius: var(--radio);
  overflow: hidden; text-decoration: none; display: flex; flex-direction: column;
  transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease;
}
a.tarjeta:hover { transform: translateY(-4px); border-color: var(--c, var(--turquesa)); box-shadow: 0 14px 40px rgba(0,0,0,.35); }
.tarjeta .foto { aspect-ratio: 16 / 9; object-fit: cover; width: 100%; background: var(--fondo-2); }
.tarjeta .cuerpo { padding: 16px 18px 20px; display: flex; flex-direction: column; gap: 6px; flex: 1; }
.tarjeta p { color: var(--suave); font-size: .95rem; margin: 0; }
.chip { align-self: flex-start; font-size: .75rem; font-weight: 800; letter-spacing: .04em; padding: 4px 10px; border-radius: 999px; background: color-mix(in srgb, var(--c, var(--turquesa)) 22%, transparent); color: var(--c, var(--turquesa)); }
.accion { margin-top: auto; padding-top: 10px; font-weight: 800; color: var(--c, var(--turquesa)); }

.boton { display: inline-flex; align-items: center; gap: 8px; padding: 12px 22px; border-radius: 999px; font-weight: 800; text-decoration: none; background: var(--coral); color: #fff; border: 0; cursor: pointer; font-size: 1rem; }
.boton.secundario { background: transparent; border: 2px solid var(--borde); color: var(--texto); }
.botones { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 8px; }

.filtros { display: flex; gap: 8px; flex-wrap: wrap; margin: 0 0 22px; }
.filtros button { font: inherit; font-weight: 800; font-size: .9rem; padding: 8px 16px; border-radius: 999px; border: 1px solid var(--borde); background: transparent; color: var(--suave); cursor: pointer; }
.filtros button.activo { background: var(--texto); color: var(--fondo); }

/* Videos */
.video-marco { border-radius: var(--radio); overflow: hidden; border: 1px solid var(--borde); background: #000; }
.video-marco video { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }
.pie { font-size: .85rem; color: var(--suave); margin-top: 8px; }
.rotulo { position: absolute; left: 12px; bottom: 12px; font-size: .72rem; font-weight: 800; letter-spacing: .05em; text-transform: uppercase; background: rgba(0,0,0,.55); padding: 4px 10px; border-radius: 999px; }
.clip { position: relative; }
.clip::after { content: ""; position: absolute; inset: 0 0 auto 0; height: 110px; background: linear-gradient(180deg, rgba(0,0,0,.7), transparent); pointer-events: none; }
.clip h3, .clip p, .clip .rotulo { z-index: 1; }
.rejilla.dos-col { grid-template-columns: repeat(auto-fill, minmax(min(100%, 420px), 1fr)); }
.rejilla.tres-col { grid-template-columns: repeat(auto-fill, minmax(min(100%, 330px), 1fr)); }

/* Línea de civilizaciones */
.franja { display: grid; grid-auto-flow: column; grid-auto-columns: minmax(220px, 260px); gap: 16px; overflow-x: auto; padding-bottom: 12px; scroll-snap-type: x mandatory; }
.franja .tarjeta { scroll-snap-align: start; }
.franja .foto { aspect-ratio: 4 / 3; }

/* Pie de página */
footer { border-top: 1px solid var(--borde); padding: 32px 0 48px; color: var(--suave); font-size: .9rem; margin-top: 40px; }

@media (max-width: 640px) {
  body { font-size: 16px; }
  .portada { padding: 48px 0 36px; }
  .portada.con-imagen { min-height: 360px; }
  .menu { margin-left: 0; width: 100%; overflow-x: auto; flex-wrap: nowrap; padding-bottom: 8px; }
  .menu a { white-space: nowrap; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; scroll-behavior: auto !important; } }