/* ==========================================================
   SCB Project · Estilos responsive (mobile first)
   ========================================================== */

:root {
  --bg: #fdfaf3;
  --ink: #1d2733;
  --muted: #56606d;
  --card: #ffffff;
  --line: #e6e0d2;

  /* Colores fijos por asignatura (contraste AA con texto blanco) */
  --science: #1f7a46;
  --lengua: #c62f36;
  --matematicas: #2862c4;
  --ingles: #b65a00;
  --course: #6a4bb8;

  --radius: 20px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: system-ui, "Segoe UI", Roboto, Arial, sans-serif;
  font-size: 1.05rem;
  line-height: 1.5;
  color: var(--ink);
  background: var(--bg);
}

/* ---------- Barra superior ---------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background: var(--card);
  border-bottom: 2px solid var(--line);
}

.brand {
  margin-right: auto;
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--ink);
  text-decoration: none;
}

.btn-icon {
  min-width: 48px;
  min-height: 48px;
  font-size: 1.4rem;
  background: #fff;
  border: 2px solid var(--line);
  border-radius: 14px;
  cursor: pointer;
}

/* Migas de pan: ocultas en móvil, visibles desde 600px */
.crumbs {
  display: none;
}

@media (min-width: 600px) {
  .crumbs {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.4rem;
    color: var(--muted);
    font-size: 1rem;
  }
  .crumbs a {
    color: var(--ink);
    padding: 0.25rem 0.4rem;
    border-radius: 8px;
  }
  .crumbs .sep {
    color: var(--muted);
  }
}

/* ---------- Contenido ---------- */

main {
  flex: 1;
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem;
  outline: none;
}

.title {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  line-height: 1.2;
  margin: 0.5rem 0 0.75rem;
}

.lead {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  color: var(--muted);
  margin: 0 0 1.25rem;
}

.grid {
  display: grid;
  gap: clamp(0.75rem, 2vw, 1.25rem);
  grid-template-columns: 1fr;
}

/* Móvil: asignaturas en 2 × 2 */
.grid.subjects {
  grid-template-columns: 1fr 1fr;
}

@media (min-width: 600px) {
  .grid.courses {
    grid-template-columns: repeat(3, 1fr);
  }
  .grid.units {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .grid.subjects {
    grid-template-columns: repeat(4, 1fr);
  }
  .grid.units {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ---------- Tarjetas ---------- */

.card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 140px;
  padding: 1.25rem;
  text-align: center;
  text-decoration: none;
  color: var(--ink);
  background: var(--card);
  border: 3px solid var(--accent, var(--line));
  border-radius: var(--radius);
  box-shadow: 0 4px 0 var(--accent, var(--line));
  transition: transform 0.15s ease;
}

.card:hover {
  transform: translateY(-2px);
}

.card.disabled {
  opacity: 0.6;
  border-style: dashed;
  box-shadow: none;
  cursor: not-allowed;
}

.card.disabled:hover {
  transform: none;
}

.course {
  --accent: var(--course);
}

.subject.s-science,
.unit.s-science {
  --accent: var(--science);
}
.subject.s-lengua,
.unit.s-lengua {
  --accent: var(--lengua);
}
.subject.s-matematicas,
.unit.s-matematicas {
  --accent: var(--matematicas);
}
.subject.s-ingles,
.unit.s-ingles {
  --accent: var(--ingles);
}

.icon {
  font-size: clamp(2.2rem, 6vw, 3.2rem);
  line-height: 1;
}

.icon.big {
  font-size: clamp(2.8rem, 8vw, 4rem);
}

.label {
  font-weight: 800;
  font-size: clamp(1.2rem, 2.5vw, 1.6rem);
}

.sub {
  color: var(--muted);
}

.unit-num {
  font-weight: 700;
  color: var(--accent);
}

.badge {
  margin-top: 0.3rem;
  padding: 0.3rem 0.8rem;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
}

.card.disabled .badge {
  background: var(--muted);
}

/* Navegación entre actividades de una unidad */
.pager {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin: 1rem 0;
}

.pager-pages {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.4rem;
}

.page-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 48px;
  min-height: 48px;
  padding: 0 0.6rem;
  font-weight: 800;
  color: var(--ink);
  text-decoration: none;
  background: #fff;
  border: 2px solid var(--line);
  border-radius: 14px;
}

.page-link[aria-current="page"] {
  color: #fff;
  background: var(--accent, var(--matematicas));
  border-color: var(--accent, var(--matematicas));
}

.btn-link.disabled {
  opacity: 0.4;
  cursor: default;
}

.grid.pages {
  grid-template-columns: 1fr;
}

@media (min-width: 600px) {
  .grid.pages {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .grid.pages {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Página de actividad externa (iframe) */
.activity-frame {
  display: block;
  width: 100%;
  height: 600px; /* se ajusta solo a la altura del contenido */
  min-height: 400px;
  border: 0;
  border-radius: var(--radius);
  background: #fff;
}

/* Unidades con temas (Lengua 6º) */
.unit-block {
  margin-bottom: 2rem;
}

.unit-title {
  margin: 0 0 0.75rem;
  font-size: clamp(1.3rem, 3vw, 1.7rem);
}

.grid.topics {
  grid-template-columns: 1fr;
}

@media (min-width: 600px) {
  .grid.topics {
    grid-template-columns: repeat(3, 1fr);
  }
}

.empty {
  padding: 2rem;
  text-align: center;
  background: #fff;
  border: 2px dashed var(--line);
  border-radius: var(--radius);
}

/* ---------- Botones ---------- */

.btn-primary,
.btn-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  padding: 0.7rem 1.4rem;
  font-size: 1.15rem;
  font-weight: 800;
  border-radius: 14px;
  text-decoration: none;
  cursor: pointer;
}

.btn-primary {
  border: none;
  background: var(--accent, var(--matematicas));
  color: #fff;
}

.btn-link {
  border: 2px solid var(--line);
  background: #fff;
  color: var(--ink);
}

.btn-audio {
  min-height: 48px;
  margin-bottom: 1rem;
  padding: 0.5rem 1rem;
  font-size: 1.05rem;
  font-weight: 700;
  background: #fff;
  border: 2px solid var(--line);
  border-radius: 14px;
  cursor: pointer;
}

:focus-visible {
  outline: 4px solid #111;
  outline-offset: 3px;
}

/* ---------- Actividad (quiz) ---------- */

.activity {
  --accent: var(--matematicas);
}
.activity.s-science {
  --accent: var(--science);
}
.activity.s-lengua {
  --accent: var(--lengua);
}
.activity.s-matematicas {
  --accent: var(--matematicas);
}
.activity.s-ingles {
  --accent: var(--ingles);
}

.quiz {
  max-width: 720px;
  margin: 0 auto;
  padding: clamp(1rem, 3vw, 2rem);
  background: #fff;
  border: 2px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 4px 0 var(--line);
}

.progress {
  margin: 0 0 0.4rem;
  font-weight: 700;
  color: var(--muted);
}

.progressbar {
  height: 14px;
  margin-bottom: 1.25rem;
  overflow: hidden;
  background: var(--line);
  border-radius: 999px;
}

.progressbar span {
  display: block;
  height: 100%;
  background: var(--accent);
  transition: width 0.3s ease;
}

.question {
  margin: 0.25rem 0 1rem;
  font-size: clamp(1.3rem, 3vw, 1.8rem);
  line-height: 1.3;
  outline: none;
}

.options {
  display: grid;
  gap: 0.75rem;
  grid-template-columns: 1fr;
  margin: 1rem 0;
}

@media (min-width: 600px) {
  .options {
    grid-template-columns: 1fr 1fr;
  }
}

.option {
  min-height: 60px;
  padding: 0.8rem 1rem;
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
  font-weight: 700;
  color: var(--ink);
  text-align: left;
  background: #fff;
  border: 3px solid var(--line);
  border-radius: 16px;
  cursor: pointer;
}

.option:hover:not(:disabled) {
  border-color: var(--accent);
}

.option.correct {
  background: #e3f6ea;
  border-color: #1f7a46;
}

.option.wrong {
  background: #fde7e7;
  border-color: #c62f36;
}

.option:disabled {
  cursor: default;
}

.feedback {
  min-height: 2rem;
  font-size: 1.15rem;
  font-weight: 700;
}

.result {
  text-align: center;
}

.stars {
  font-size: clamp(2.5rem, 8vw, 4rem);
  letter-spacing: 0.3rem;
  margin: 0.5rem 0;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.muted {
  color: var(--muted);
}

/* ---------- Pie y utilidades ---------- */

.footer {
  padding: 1rem;
  text-align: center;
  font-size: 0.95rem;
  color: var(--muted);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
    scroll-behavior: auto !important;
  }
}