@import url('https://fonts.googleapis.com/css2?family=Caveat:wght@400;600;700&family=Gloria+Hallelujah&display=swap');

:root {
  --madera: #6b3a2a;
  --madera-clara: #8b5a2b;
  --madera-oscura: #4a2a1a;
  --pizarra: #2b4c3e;
  --pizarra-clara: #345e4c;
  --tiza: #f2f0e8;
  --tiza-tenue: #d6d3c8;
  --tiza-amarilla: #ffd93d;
  --tiza-rosa: #ff6b6b;
  --tiza-verde: #5fdb8f;
  --tiza-azul: #6eb5ff;
  --tiza-naranja: #ffb347;
  --tiza-morada: #c39bdb;
  --tiza-blanca: #fdfcf7;
  --trazo: 3px dashed rgba(255,255,255,0.18);
  --radio: 8px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

/* Fondo de aula con madera */
html {
  background: linear-gradient(135deg, #8b5a2b 0%, #6b3a2a 30%, #5a3520 60%, #7a4a2e 100%);
  min-height: 100vh;
}

body {
  font-family: 'Caveat', 'Gloria Hallelujah', 'Comic Sans MS', cursive, sans-serif;
  color: var(--tiza);
  background:
    /* borde madera */
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 3px,
      rgba(0,0,0,0.08) 3px,
      rgba(0,0,0,0.08) 6px
    ),
    /* polvo de tiza sutil */
    radial-gradient(ellipse at 20% 50%, rgba(255,255,255,0.03) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(255,255,255,0.02) 0%, transparent 40%);
  line-height: 1.6;
  max-width: 920px;
  margin: 0 auto;
  padding: 6px 10px 40px;
  /* Marco de madera */
  border-left: 22px solid var(--madera);
  border-right: 22px solid var(--madera);
  border-bottom: 16px solid var(--madera-oscura);
  box-shadow:
    inset 0 0 60px rgba(0,0,0,0.25),
    4px 4px 14px rgba(0,0,0,0.4);
  min-height: 100vh;
}
body::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0; height: 5px;
  background: linear-gradient(to bottom, var(--madera-oscura), var(--madera-clara));
  box-shadow: 0 2px 8px rgba(0,0,0,0.5);
  z-index: 10;
}

/* Zona de tiza (bandeja) inferior */
body::after {
  content: '🧽🖍️';
  display: block;
  text-align: right;
  padding: 8px 16px 0 0;
  font-size: 1.4rem;
  letter-spacing: 6px;
  border-top: 4px solid var(--madera-clara);
  margin-top: 24px;
  opacity: 0.7;
}

/* ---------- Cabecera ---------- */
header {
  text-align: center;
  padding: 20px 16px 6px;
  position: relative;
}
header h1 {
  font-family: 'Gloria Hallelujah', 'Caveat', cursive;
  font-size: 2.2rem;
  color: var(--tiza-blanca);
  text-shadow: 1px 1px 0 rgba(0,0,0,0.5), 0 0 12px rgba(255,255,200,0.15);
  letter-spacing: 1px;
  margin-bottom: 0;
}
header p {
  color: var(--tiza-tenue);
  font-size: 1.2rem;
  opacity: 0.85;
}

/* ---------- Pestañas (tiza en pizarra) ---------- */
.tabs {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin: 12px auto 6px;
  padding: 6px 12px;
}
.tab-btn {
  border: 2px dashed var(--tiza-tenue);
  background: transparent;
  color: var(--tiza);
  padding: 10px 22px;
  border-radius: 6px;
  font-size: 1.15rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: .15s;
  text-shadow: 1px 1px 0 rgba(0,0,0,0.3);
}
.tab-btn:hover { background: rgba(255,255,255,0.06); }
.tab-btn.active { background: rgba(255,255,255,0.12); border-color: var(--tiza-amarilla); color: var(--tiza-amarilla); box-shadow: 0 0 14px rgba(255,217,60,0.25); }

/* ---------- Contenedor ---------- */
.container { padding: 0 10px; }
.screen { display: none; }
.screen.active { display: block; }

/* ---------- Tarjetas (zonas de tiza) ---------- */
.card {
  background: rgba(0,0,0,0.15);
  border: var(--trazo);
  border-radius: var(--radio);
  padding: 18px 20px;
  margin-top: 14px;
}
.card h2 { font-size: 1.4rem; margin-bottom: 6px; color: var(--tiza-amarilla); }
.card h3 { font-size: 1.1rem; margin: 8px 0 4px; color: var(--tiza-azul); }

/* ---------- Anuncios ---------- */
.ad-slot {
  background: rgba(0,0,0,0.25);
  border: 2px dotted var(--tiza-tenue);
  border-radius: 6px;
  color: var(--tiza-tenue);
  font-size: .9rem;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 90px;
  margin: 12px auto;
  max-width: 920px;
  text-align: center;
  padding: 8px;
}
.ad-slot.inline { min-height: 240px; margin-top: 20px; }

/* ---------- Formularios ---------- */
.inputs {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 14px;
  margin: 10px 0 16px;
}
.field label { display: block; font-weight: 700; margin-bottom: 4px; font-size: 1rem; color: var(--tiza-tenue); }
.field input {
  width: 140px;
  font-size: 1.4rem;
  padding: 8px 10px;
  background: rgba(0,0,0,0.3);
  border: 2px dashed var(--tiza-tenue);
  border-radius: 6px;
  color: var(--tiza-blanca);
  text-align: center;
  font-family: inherit;
}
.field input:focus { outline: none; border-color: var(--tiza-amarilla); box-shadow: 0 0 10px rgba(255,217,60,0.3); }

select {
  background: rgba(0,0,0,0.3);
  border: 2px dashed var(--tiza-tenue);
  color: var(--tiza-blanca);
  font-family: inherit;
}

.btn {
  border: 2px dashed var(--tiza-tenue);
  border-radius: 6px;
  padding: 10px 20px;
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
  font-family: inherit;
  transition: .15s;
  background: transparent;
  color: var(--tiza);
  text-shadow: 1px 1px 0 rgba(0,0,0,0.3);
}
.btn:hover { background: rgba(255,255,255,0.08); }
.btn:disabled { opacity: .4; cursor: not-allowed; }
.btn-primary { border-color: var(--tiza-azul); color: var(--tiza-azul); }
.btn-green { border-color: var(--tiza-verde); color: var(--tiza-verde); }
.btn-orange { border-color: var(--tiza-naranja); color: var(--tiza-naranja); }
.btn-ghost { border-color: var(--tiza-tenue); color: var(--tiza-tenue); }
.btn-sm { padding: 7px 14px; font-size: .95rem; }

/* ---------- Barra de juego ---------- */
.gamebar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  background: rgba(0,0,0,0.2);
  border: 2px dashed var(--tiza-amarilla);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 6px 0 14px;
}
.gstat { display: flex; align-items: baseline; gap: 4px; font-size: 1.1rem; color: var(--tiza); }
.gstat b { font-size: 1.3rem; color: var(--tiza-amarilla); }
.gstat small { color: var(--tiza-tenue); font-weight: 400; }
.gstar { margin-left: auto; font-size: 1.5rem; letter-spacing: 3px; color: var(--tiza-amarilla); }

/* Confeti (en pizarra, trocitos de tiza) */
.confetti {
  position: fixed;
  top: -10px;
  width: 8px;
  height: 12px;
  z-index: 9999;
  pointer-events: none;
  border-radius: 2px;
  animation: caer 2.6s ease-in forwards;
}
@keyframes caer {
  0% { transform: translateY(0) rotate(0); opacity: 1; }
  100% { transform: translateY(105vh) rotate(900deg); opacity: 0; }
}

/* ---------- División en pizarra ---------- */
.division-wrap { margin-top: 10px; }
.division-box {
  background: rgba(0,0,0,0.2);
  border: 2px dashed var(--tiza-tenue);
  border-radius: 6px;
  padding: 10px 12px;
  display: inline-block;
  font-family: 'Caveat', 'Comic Sans MS', cursive, monospace;
  font-size: 1.35rem;
}
.div-row {
  display: flex;
  align-items: center;
  line-height: 1.35;
}
.div-num {
  display: inline-block;
  min-width: 1.5ch;
  text-align: center;
  font-weight: 600;
  color: var(--tiza);
}
.div-num.gap { color: transparent; }
.div-num.qdigit { color: var(--tiza-azul); font-weight: 700; }
.div-num.div, .div-num.divisor { color: var(--tiza-blanca); }
.div-num.prod { color: var(--tiza-naranja); }
.div-num.rem { color: var(--tiza-verde); font-weight: 700; }
.div-num.bor { color: var(--tiza-amarilla); font-weight: 700; }
.div-num.line, .div-num.bar { color: var(--tiza-tenue); }

/* Explicación por pasos */
.explain {
  background: rgba(0,0,0,0.2);
  border-left: 4px solid var(--tiza-azul);
  padding: 10px 12px;
  border-radius: 6px;
  margin: 10px 0;
  font-size: 1.1rem;
  color: var(--tiza);
}
.explain.muted { border-left-color: var(--tiza-morada); }

/* ---------- Practica ---------- */
.problem-display {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--tiza-blanca);
  background: rgba(0,0,0,0.2);
  border: 2px dashed var(--tiza-azul);
  border-radius: 8px;
  padding: 14px;
  margin: 4px 0;
  text-shadow: 1px 1px 0 rgba(0,0,0,0.5);
}
.problem-display .op { margin: 0 14px; color: var(--tiza-amarilla); }

.current-question {
  background: rgba(255,217,60,0.08);
  border: 2px dashed var(--tiza-amarilla);
  border-radius: 8px;
  padding: 12px 14px;
  margin: 10px 0;
  font-size: 1.15rem;
  color: var(--tiza);
}
.answer-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
  flex-wrap: wrap;
}
.answer-row input {
  font-size: 1.5rem;
  padding: 8px 12px;
  width: 90px;
  text-align: center;
  background: rgba(0,0,0,0.3);
  border: 2px dashed var(--tiza-tenue);
  border-radius: 6px;
  color: var(--tiza-blanca);
  font-family: inherit;
}
.answer-row input:focus { outline: none; border-color: var(--tiza-amarilla); box-shadow: 0 0 12px rgba(255,217,60,0.3); }
.answer-row .lbl { font-weight: 700; font-size: 1.05rem; }

/* ---------- Chat de ayuda ---------- */
.chat {
  margin-top: 14px;
  background: rgba(0,0,0,0.25);
  border: 2px dashed var(--tiza-tenue);
  border-radius: 8px;
  overflow: hidden;
}
.chat-head {
  background: rgba(0,0,0,0.3);
  padding: 9px 14px;
  font-weight: 700;
  color: var(--tiza-amarilla);
  border-bottom: 1px dashed rgba(255,255,255,0.1);
  font-size: 1.05rem;
}
.chat-body {
  padding: 10px 14px;
  max-height: 360px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.bubble {
  max-width: 85%;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 1.05rem;
  animation: pop .2s ease;
}
.bubble.bot { background: rgba(60,80,70,0.5); align-self: flex-start; border: 1px dashed var(--tiza-tenue); color: var(--tiza); }
.bubble.user { background: rgba(0,80,140,0.4); color: var(--tiza-blanca); align-self: flex-end; border: 1px dashed var(--tiza-azul); }
.bubble.hint { background: rgba(255,180,0,0.12); align-self: flex-start; border: 1px dashed var(--tiza-amarilla); color: var(--tiza-amarilla); }
.bubble.success { background: rgba(80,200,120,0.12); border: 1px dashed var(--tiza-verde); color: var(--tiza-verde); align-self: flex-start; }
@keyframes pop { from { transform: scale(.95); opacity: 0; } to { transform: scale(1); opacity: 1; } }

.chat-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  padding: 8px 14px;
  border-top: 1px dashed rgba(255,255,255,0.1);
  background: rgba(0,0,0,0.2);
}

/* Resultado éxito */
.success-banner {
  background: rgba(95,219,143,0.12);
  border: 2px dashed var(--tiza-verde);
  color: var(--tiza-verde);
  text-align: center;
  padding: 16px;
  border-radius: 8px;
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 14px;
}
.hidden { display: none !important; }

footer {
  text-align: center;
  color: var(--tiza-tenue);
  font-size: .85rem;
  margin-top: 24px;
  padding: 0 14px;
  opacity: 0.7;
}

@media (max-width: 540px) {
  body { border-left-width: 10px; border-right-width: 10px; }
  header h1 { font-size: 1.6rem; }
  .tab-btn { padding: 8px 12px; font-size: .95rem; }
  .problem-display { font-size: 2rem; }
}