/* Estructura: cabecera, pie, secciones, portada y páginas interiores. */

.ancho {
  width: 100%;
  max-width: calc(var(--ancho) + 2 * var(--margen));
  margin-inline: auto;
  padding-inline: var(--margen);
}

.saltar {
  position: absolute;
  left: 8px;
  top: -60px;
  z-index: 40;
  padding: 8px 14px;
  background: var(--blanco);
  border-radius: var(--radio-s);
}

.saltar:focus {
  top: 8px;
}

/* Cabecera */

.cabecera {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(250, 251, 252, 0.82);
  -webkit-backdrop-filter: saturate(160%) blur(16px);
  backdrop-filter: saturate(160%) blur(16px);
  border-bottom: 1px solid var(--linea);
}

.cabecera__fila {
  display: flex;
  align-items: center;
  gap: 20px;
  min-height: var(--alto-cabecera);
}

.marca {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--tinta);
  text-decoration: none;
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.marca:hover {
  color: var(--tinta);
}

.marca__sello {
  display: block;
  width: 32px;
  height: 32px;
  border-radius: 9px;
  box-shadow: 0 6px 14px -6px rgba(22, 58, 125, 0.6);
  transition: transform 0.3s var(--curva);
}

.marca:hover .marca__sello {
  transform: rotate(-6deg) scale(1.05);
}

.nav {
  display: flex;
  gap: 2px;
  margin-left: auto;
}

.nav a {
  padding: 7px 14px;
  border-radius: 999px;
  color: var(--suave);
  text-decoration: none;
  white-space: nowrap;
  font-size: 0.94rem;
  font-weight: 500;
  transition: background-color 0.2s, color 0.2s;
}

.nav a:hover {
  background: var(--velo);
  color: var(--tinta);
}

.nav a[aria-current="page"] {
  background: var(--azul-100);
  color: var(--azul-700);
}

.cabecera .cabecera__cta {
  padding: 9px 16px;
  font-size: 0.92rem;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.18), 0 6px 14px -8px rgba(22, 58, 125, 0.6);
}

.cabecera__menu {
  display: none;
  margin-left: auto;
  padding: 9px;
  background: var(--blanco);
  border: 1px solid var(--linea-fuerte);
  border-radius: var(--radio-s);
  color: var(--tinta);
  font-size: 1.15rem;
  line-height: 0;
  cursor: pointer;
}

@media (max-width: 1040px) {
  .cabecera__fila {
    flex-wrap: wrap;
    gap: 0 14px;
  }

  .cabecera__menu {
    display: inline-flex;
  }

  .cabecera .cabecera__cta {
    display: none;
  }

  .nav {
    display: none;
    flex-direction: column;
    flex-basis: 100%;
    gap: 4px;
    margin: 0;
    padding: 8px 0 16px;
  }

  .cabecera.es-abierta .nav {
    display: flex;
  }

  .nav a {
    padding: 12px 16px;
    border-radius: var(--radio-s);
    font-size: 1.02rem;
  }
}

/* Pie */

.pie {
  padding: 48px 0 40px;
  background: var(--azul-950);
  color: rgba(255, 255, 255, 0.62);
  font-size: 0.94rem;
}

.pie__rejilla {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 32px;
}

.pie__marca {
  margin-bottom: 6px;
  color: var(--blanco);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.pie__nota {
  margin: 0;
}

.pie__titulo {
  margin-bottom: 12px;
  color: var(--oro-400);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.pie li + li {
  margin-top: 8px;
}

.pie a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
}

.pie a:hover {
  color: var(--blanco);
}

@media (max-width: 760px) {
  .pie__rejilla {
    grid-template-columns: 1fr 1fr;
  }

  .pie__rejilla > :first-child {
    grid-column: 1 / -1;
  }
}

/* Secciones */

.seccion {
  padding: 96px 0 0;
}

.seccion--velo {
  margin-top: 96px;
  padding: 88px 0;
  background: var(--velo);
  border-block: 1px solid var(--linea);
}

.seccion--oscura {
  position: relative;
  margin-top: 96px;
  padding: 96px 0 88px;
  background: var(--azul-950);
  color: rgba(255, 255, 255, 0.7);
  overflow: hidden;
}

.seccion--velo + .seccion--oscura {
  margin-top: 0;
}

.seccion--oscura::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(640px 380px at 12% 0%, rgba(47, 107, 214, 0.42), transparent 70%),
    radial-gradient(520px 340px at 92% 100%, rgba(189, 156, 87, 0.16), transparent 70%);
  pointer-events: none;
}

.seccion--oscura > * {
  position: relative;
}

.seccion--oscura + .pie,
main:has(.seccion--oscura:last-child) + .pie {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.cabeza-seccion {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px 40px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.cabeza-seccion__texto {
  max-width: 640px;
}

.cabeza-seccion h2 {
  margin-top: 12px;
}

.cabeza-seccion p:not(.antetitulo) {
  margin: 14px 0 0;
  color: var(--suave);
  font-size: 1.1rem;
}

.seccion--oscura h2 {
  color: var(--blanco);
}

.seccion--oscura .cabeza-seccion p:not(.antetitulo) {
  color: rgba(255, 255, 255, 0.66);
}

.rejilla {
  display: grid;
  gap: 24px;
}

.rejilla--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.rejilla--4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

@media (max-width: 1040px) {
  .rejilla--4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 820px) {
  .rejilla--2 {
    grid-template-columns: minmax(0, 1fr);
  }

  .seccion {
    padding-top: 64px;
  }

  .seccion--velo,
  .seccion--oscura {
    margin-top: 64px;
    padding: 64px 0;
  }

  .cabeza-seccion {
    margin-bottom: 28px;
  }
}

@media (max-width: 540px) {
  .rejilla--4 {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* Portada */

.heroe {
  position: relative;
  padding: 72px 0 0;
  overflow: hidden;
}

.heroe::before {
  content: "";
  position: absolute;
  inset: 0 0 -1px;
  background:
    radial-gradient(700px 460px at 86% 18%, rgba(47, 107, 214, 0.16), transparent 68%),
    radial-gradient(520px 380px at 0% 52%, rgba(189, 156, 87, 0.14), transparent 70%);
  pointer-events: none;
}

.heroe::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(22, 58, 125, 0.06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(22, 58, 125, 0.06) 1px, transparent 1px);
  background-size: 56px 56px;
  -webkit-mask-image: radial-gradient(900px 520px at 70% 30%, #000, transparent 75%);
  mask-image: radial-gradient(900px 520px at 70% 30%, #000, transparent 75%);
  pointer-events: none;
}

.heroe > * {
  position: relative;
  z-index: 1;
}

.heroe__rejilla {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.04fr);
  gap: 56px;
  align-items: center;
}

.heroe h1 {
  margin: 22px 0 22px;
  font-size: clamp(2.5rem, 5.4vw, 4.1rem);
  line-height: 1.02;
  letter-spacing: -0.045em;
}

.heroe h1 strong {
  font-weight: inherit;
  background: var(--degradado);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.heroe__entradilla {
  max-width: 54ch;
  margin-bottom: 30px;
  color: var(--suave);
  font-size: 1.16rem;
  line-height: 1.55;
}

.heroe__acciones {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.heroe__areas {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 34px;
}

@media (max-width: 980px) {
  .heroe {
    padding-top: 44px;
  }

  .heroe__rejilla {
    grid-template-columns: minmax(0, 1fr);
    gap: 40px;
  }
}

/* Cabecera de página (nivel y lección) */

.cabeza-pagina {
  position: relative;
  padding: 36px 0 44px;
  border-bottom: 1px solid var(--linea);
  overflow: hidden;
}

.cabeza-pagina::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(560px 300px at 92% 0%, rgba(47, 107, 214, 0.12), transparent 70%),
    radial-gradient(420px 260px at 0% 100%, rgba(189, 156, 87, 0.12), transparent 70%),
    var(--blanco);
  pointer-events: none;
}

.cabeza-pagina > * {
  position: relative;
}

.cabeza-pagina h1 {
  margin: 14px 0 14px;
  max-width: 20ch;
}

.cabeza-pagina__texto {
  max-width: 62ch;
  margin-bottom: 22px;
  color: var(--suave);
  font-size: 1.14rem;
}

.cabeza-pagina__fila {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}

.cabeza-pagina__numero {
  font-family: var(--mono);
  font-size: clamp(4rem, 12vw, 8rem);
  font-weight: 500;
  line-height: 0.8;
  letter-spacing: -0.06em;
  background: linear-gradient(180deg, var(--azul-200), transparent 115%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  user-select: none;
}

.migas {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 22px;
  color: var(--tenue);
  font-size: 0.9rem;
}

.migas a {
  color: var(--suave);
  text-decoration: none;
}

.migas a:hover {
  color: var(--azul-600);
}

.meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
}

/* Nivel: lista + lateral */

.dos-columnas {
  display: grid;
  grid-template-columns: minmax(0, 1.75fr) minmax(280px, 1fr);
  gap: 48px;
  padding-top: 48px;
  padding-bottom: 96px;
  align-items: start;
}

.lateral {
  display: grid;
  gap: 16px;
  position: sticky;
  top: calc(var(--alto-cabecera) + 24px);
}

@media (max-width: 940px) {
  .dos-columnas {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
    padding-top: 32px;
    padding-bottom: 64px;
  }

  .lateral {
    position: static;
  }
}

/* Lección: índice + cuerpo */

.lectura {
  position: fixed;
  top: var(--alto-cabecera);
  left: 0;
  right: 0;
  z-index: 25;
  height: 3px;
  pointer-events: none;
}

.lectura span {
  display: block;
  height: 100%;
  width: 100%;
  background: var(--degradado);
  transform-origin: left;
  transform: scaleX(0);
}

.leccion {
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: 64px;
  padding-top: 48px;
  padding-bottom: 96px;
  align-items: start;
}

.leccion__indice {
  position: sticky;
  top: calc(var(--alto-cabecera) + 28px);
  font-size: 0.92rem;
}

.leccion__indice ol {
  margin-top: 14px;
  border-left: 1px solid var(--linea-fuerte);
}

.leccion__indice button {
  display: block;
  width: 100%;
  margin-left: -1px;
  padding: 7px 0 7px 16px;
  background: none;
  border: 0;
  border-left: 2px solid transparent;
  color: var(--suave);
  text-align: left;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
}

.leccion__indice button:hover {
  color: var(--tinta);
}

.leccion__indice button.es-activa {
  color: var(--azul-700);
  border-left-color: var(--azul-600);
  font-weight: 500;
}

.leccion__cuerpo {
  min-width: 0;
  max-width: 820px;
  counter-reset: parte;
}

@media (max-width: 940px) {
  .leccion {
    grid-template-columns: minmax(0, 1fr);
    padding-top: 28px;
    padding-bottom: 64px;
  }

  .leccion__indice {
    display: none;
  }
}

.aviso-vacio {
  padding-top: 88px;
  padding-bottom: 96px;
}

.aviso-vacio h1 {
  margin-bottom: 12px;
}

.aviso-vacio p {
  color: var(--suave);
}