/* =====================================================================
   Mathex — estilos de la app del alumno
   ===================================================================== */
:root {
  --bg: #f4f5fb;
  --card: #ffffff;
  --ink: #181b2e;
  --muted: #6a7088;
  --line: #e2e5f0;
  --accent: #4b4fe0;
  --accent-soft: #ecedfd;
  --accent-ink: #ffffff;
  --fuego: #f26b1d;
  --fuego-soft: #fff0e6;
  --ok: #17905a;   --ok-bg: #e4f6ec;
  --bad: #cc3b55;  --bad-bg: #fcebef;
  --warn: #9a6400; --warn-bg: #fff3d6;
  --info: #3c5a9a; --info-bg: #e8effc;
  --radio: 16px;
  --sombra: 0 1px 2px rgba(24, 27, 46, .05), 0 4px 16px rgba(24, 27, 46, .05);
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #10121b; --card: #1a1d2b; --ink: #eceef6; --muted: #9ba1b9; --line: #2a2e40;
    --accent: #8b8ffb; --accent-soft: #24264a; --accent-ink: #0f1128;
    --fuego: #ff9a55; --fuego-soft: #3a2414;
    --ok: #4fd39a; --ok-bg: #12301f; --bad: #ff7d95; --bad-bg: #3a1720;
    --warn: #ffc85e; --warn-bg: #352a10; --info: #9ab8ff; --info-bg: #19243c;
    --sombra: none;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { overflow-x: hidden; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.5 "Nunito", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-tap-highlight-color: transparent;
}
#app { max-width: 560px; margin: 0 auto; padding: 12px 16px 48px; min-height: 100vh; }
a { color: var(--accent); }
h1, h2 { line-height: 1.2; }

/* ---------- Botones y formularios ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font: inherit; font-weight: 800; padding: 12px 18px; border-radius: 14px; border: 0;
  background: var(--accent-soft); color: var(--accent); cursor: pointer; text-decoration: none;
}
.btn.primario { background: var(--accent); color: var(--accent-ink); }
.btn.peligro { background: var(--bad-bg); color: var(--bad); width: 100%; margin-top: 16px; }
.btn.texto { background: none; padding: 8px 0; font-weight: 700; }
.btn:disabled { opacity: .6; }
.btn.cargando::after {
  content: ""; width: 14px; height: 14px; border-radius: 50%;
  border: 2px solid currentColor; border-right-color: transparent; animation: gira .7s linear infinite;
}
@keyframes gira { to { transform: rotate(360deg); } }

label { display: block; font-weight: 700; font-size: 14px; margin-bottom: 12px; }
label small { font-weight: 400; color: var(--muted); }
input {
  display: block; width: 100%; margin-top: 4px; font: inherit; font-size: 17px;
  padding: 12px 14px; border-radius: 12px; border: 1.5px solid var(--line);
  background: var(--bg); color: var(--ink);
}
input:focus { outline: none; border-color: var(--accent); }
.dos { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.check { display: flex; gap: 10px; align-items: center; font-weight: 600; }
.check input { width: 20px; height: 20px; margin: 0; flex: none; }
fieldset { border: 0; padding: 0; margin: 4px 0 14px; }
legend { font-weight: 700; font-size: 14px; margin-bottom: 8px; }
.error { color: var(--bad); font-weight: 700; font-size: 14px; min-height: 0; }
.error:not(:empty) { margin: 4px 0 12px; }

.tarjeta { background: var(--card); border: 1px solid var(--line); border-radius: var(--radio); padding: 18px; box-shadow: var(--sombra); }
.centro { text-align: center; }
.tenue { color: var(--muted); }
.grande { font-size: 48px; }

.nota { padding: 10px 14px; border-radius: 12px; margin: 12px 0; font-weight: 600; font-size: 14px; }
.nota.ok { background: var(--ok-bg); color: var(--ok); }
.nota.bad { background: var(--bad-bg); color: var(--bad); }
.nota.info { background: var(--info-bg); color: var(--info); }

/* ---------- Acceso ---------- */
.acceso { padding-top: 6vh; }
.acceso .tarjeta .btn { width: 100%; margin-top: 4px; }
.marca { text-align: center; margin-bottom: 24px; }
.logo { font-size: 44px; font-weight: 900; letter-spacing: -1.5px; }
.logo b { color: var(--accent); }
.marca p { margin: 4px 0 0; color: var(--muted); }
.alterno { text-align: center; color: var(--muted); }
.encabezado-simple { display: flex; align-items: center; gap: 12px; margin: 4px 0 16px; }
.encabezado-simple h1 { margin: 0; font-size: 24px; }
.atras {
  width: 40px; height: 40px; flex: none; display: grid; place-items: center; border-radius: 12px;
  background: var(--card); border: 1px solid var(--line); text-decoration: none; color: var(--ink); font-size: 20px;
}

.avatares { display: grid; grid-template-columns: repeat(6, 1fr); gap: 8px; }
.avatar-op { margin: 0; cursor: pointer; position: relative; }
.avatar-op input { position: absolute; inset: 0; width: 1px; height: 1px; margin: 0; opacity: 0; pointer-events: none; }
.avatar-op span {
  display: grid; place-items: center; aspect-ratio: 1; font-size: 26px; border-radius: 14px;
  border: 2px solid var(--line); background: var(--bg);
}
.avatar-op input:checked + span { border-color: var(--accent); background: var(--accent-soft); transform: scale(1.06); }
.avatar-op input:focus-visible + span { outline: 2px solid var(--accent); }

.aviso { margin-bottom: 10px; font-size: 14px; }
.aviso summary { cursor: pointer; color: var(--accent); font-weight: 700; }
.aviso-texto { white-space: pre-line; color: var(--muted); max-height: 220px; overflow: auto; padding: 8px 0; }

/* ---------- Inicio ---------- */
.barra { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 4px 0 12px; }
.yo { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.yo small { display: block; color: var(--muted); font-size: 13px; line-height: 1; }
.yo b { font-size: 18px; }
.avatar {
  width: 46px; height: 46px; display: grid; place-items: center; font-size: 26px;
  border-radius: 50%; background: var(--accent-soft);
}
.avatar.grande { width: 88px; height: 88px; font-size: 50px; margin: 0 auto 8px; }
.racha {
  display: flex; align-items: center; gap: 4px; padding: 6px 12px; border-radius: 999px;
  background: var(--card); border: 1px solid var(--line); color: var(--muted); filter: grayscale(1);
}
.racha.viva { background: var(--fuego-soft); border-color: transparent; color: var(--fuego); filter: none; }

.resumen { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.resumen div { background: var(--card); border: 1px solid var(--line); border-radius: var(--radio); padding: 12px 14px; }
.resumen b { display: block; font-size: 26px; line-height: 1.1; }
.resumen small { color: var(--muted); }

.seccion { font-size: 15px; text-transform: uppercase; letter-spacing: .6px; color: var(--muted); margin: 24px 0 10px; }
.temas { display: grid; gap: 10px; }
.tema {
  display: flex; align-items: center; gap: 12px; padding: 12px 14px; border-radius: var(--radio);
  background: var(--card); border: 1px solid var(--line); text-decoration: none; color: var(--ink); box-shadow: var(--sombra);
}
.tema:active { transform: scale(.99); }
.tema-icono {
  width: 46px; height: 46px; flex: none; display: grid; place-items: center; border-radius: 12px;
  background: var(--accent-soft); color: var(--accent); font-weight: 900; font-size: 18px;
}
.tema-info { flex: 1; min-width: 0; }
.tema-info b { display: block; }
.tema-info small { color: var(--muted); }
.puntos { display: inline-flex; gap: 4px; vertical-align: middle; }
.puntos i { width: 8px; height: 8px; border-radius: 50%; background: var(--line); }
.puntos i.on { background: var(--accent); }
.sello { font-size: 22px; }

.grupos { display: grid; gap: 10px; }
.grupo { background: var(--card); border: 1px solid var(--line); border-radius: var(--radio); padding: 14px; }
.grupo > b { display: block; }
.grupo > small { color: var(--muted); }
.aviso-grupo { margin-top: 10px; padding: 10px 12px; border-radius: 12px; background: var(--bg); font-size: 14px; }
.aviso-grupo p { margin: 2px 0 0; color: var(--muted); }
.vacio { color: var(--muted); margin: 0; }
.unirse { display: flex; gap: 8px; }
.unirse input { margin: 0; text-transform: uppercase; letter-spacing: 1px; }
.unirse input::placeholder { text-transform: none; letter-spacing: 0; }

/* ---------- Práctica ---------- */
.barra.practica .titulo { flex: 1; min-width: 0; }
.barra.practica .titulo b { display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.barra.practica .titulo small { color: var(--muted); display: flex; align-items: center; gap: 8px; }
.marcador { font-weight: 800; color: var(--muted); font-variant-numeric: tabular-nums; }
.progreso { height: 6px; border-radius: 6px; background: var(--line); overflow: hidden; margin-bottom: 14px; }
.progreso div { height: 100%; width: 0; background: var(--accent); border-radius: 6px; transition: width .35s ease; }

.progreso { margin-bottom: 8px; }
.estado-ronda { font-size: 14px; color: var(--muted); margin-bottom: 12px; }
.estado-ronda b { color: var(--ink); }
.estado-ronda.no-alcanza { color: var(--warn); }
.nota-pista { display: block; margin-top: 4px; font-weight: 600; opacity: .85; }
.fin-ronda { text-align: center; padding: 28px 20px; }
.fin-ronda h2 { margin: 6px 0; }
.fin-ronda .resultado { font-size: 20px; margin: 4px 0 10px; }
.fin-ronda .resultado b { font-size: 44px; }
.fin-ronda.aprobada .resultado b { color: var(--ok); }
.fin-ronda.reprobada .resultado b { color: var(--fuego); }
.fin-ronda .btn { margin-top: 10px; width: 100%; }
.ejercicio .enunciado { font-size: 18px; min-height: 90px; }
.ejercicio .enunciado .katex-display { margin: 14px 0 6px; font-size: 1.3em; overflow-x: auto; overflow-y: hidden; padding: 2px 0; }
.ayuda { color: var(--muted); font-size: 13px; margin: 6px 0 14px; }
.fila { display: flex; gap: 8px; }
.fila input { margin: 0; font-size: 19px; }
.feedback { display: none; margin-top: 14px; padding: 12px 14px; border-radius: 12px; font-weight: 600; }
.feedback.ok { display: block; background: var(--ok-bg); color: var(--ok); }
.feedback.bad { display: block; background: var(--bad-bg); color: var(--bad); }
.feedback.warn { display: block; background: var(--warn-bg); color: var(--warn); }
.acciones-ej { display: flex; justify-content: space-between; margin-top: 6px; }
.btn.texto.tenue { color: var(--muted); font-weight: 600; }
.pista { display: none; margin-top: 12px; padding: 10px 14px; border-radius: 12px; background: var(--accent-soft); color: var(--ink); }
.pista.visible { display: block; }
.pista .katex-display { margin: 6px 0; text-align: left; overflow-x: auto; }
.pista .katex-display > .katex { text-align: left; }
.pista small { color: var(--muted); }
.pasos { display: none; margin-top: 12px; padding-top: 10px; border-top: 1px dashed var(--line); }
.pasos.visible { display: block; }
.pasos ol { margin: 6px 0 0; padding-left: 22px; }
.pasos .katex-display { margin: 4px 0; text-align: left; overflow-x: auto; }
.pasos .katex-display > .katex { text-align: left; }

/* ---------- Otros ---------- */
.cargando-pantalla { padding: 30vh 0; text-align: center; color: var(--muted); }
#toast {
  position: fixed; left: 50%; bottom: 24px; transform: translate(-50%, 20px); opacity: 0;
  background: var(--ink); color: var(--bg); padding: 10px 16px; border-radius: 12px; font-weight: 700;
  transition: .25s; pointer-events: none; max-width: calc(100% - 32px); text-align: center; z-index: 10;
}
#toast.visible { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 380px) {
  .avatares { grid-template-columns: repeat(4, 1fr); }
  .dos { grid-template-columns: 1fr; gap: 0; }
}