/* Tablero de Límites: mobile-first, claro/oscuro según el sistema, pensado para estudiar con el dedo. */
@font-face { font-family: 'Jakarta'; src: url('vendor/fuentes/plus-jakarta-sans-latin-500-normal.woff2') format('woff2'); font-weight: 500; font-display: swap; }
@font-face { font-family: 'Jakarta'; src: url('vendor/fuentes/plus-jakarta-sans-latin-700-normal.woff2') format('woff2'); font-weight: 700; font-display: swap; }
@font-face { font-family: 'Jakarta'; src: url('vendor/fuentes/plus-jakarta-sans-latin-800-normal.woff2') format('woff2'); font-weight: 800; font-display: swap; }

:root {
  --fondo: #F5F7FC; --panel: #FFFFFF; --panel-2: #EEF2FB; --texto: #10172F; --suave: #5A6788;
  --borde: #DDE3F1; --acento: #3B6CF6; --ok: #0E9F6E; --mal: #E0475E; --aviso: #C47F00;
  --sombra: 0 6px 24px rgba(16, 23, 47, 0.07); --c: var(--acento);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --fondo: #0B1020; --panel: #121A33; --panel-2: #18223F; --texto: #EEF2FF; --suave: #97A5CC;
    --borde: rgba(255, 255, 255, 0.1); --acento: #6E95FF; --ok: #2BD69C; --mal: #FF6B81; --aviso: #FFB020;
    --sombra: 0 6px 24px rgba(0, 0, 0, 0.35);
  }
}
:root[data-theme="dark"] {
  --fondo: #0B1020; --panel: #121A33; --panel-2: #18223F; --texto: #EEF2FF; --suave: #97A5CC;
  --borde: rgba(255, 255, 255, 0.1); --acento: #6E95FF; --ok: #2BD69C; --mal: #FF6B81; --aviso: #FFB020;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--fondo); color: var(--texto); font-family: 'Jakarta', 'Segoe UI', system-ui, sans-serif; font-size: 16px; line-height: 1.5; -webkit-font-smoothing: antialiased; }
a { color: inherit; }
button { font: inherit; color: inherit; cursor: pointer; }
.katex { font-size: 1.12em; }
.katex-display { margin: 0.4em 0; overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

/* ---------- Cabecera ---------- */
.cab { position: sticky; top: 0; z-index: 10; background: color-mix(in srgb, var(--fondo) 88%, transparent); backdrop-filter: blur(10px); border-bottom: 1px solid var(--borde); }
.marca { display: none; }
.pestanas { display: flex; justify-content: space-around; padding: 6px 4px; max-width: 900px; margin: 0 auto; }
.pestanas a { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 6px 2px; text-decoration: none; font-size: 11.5px; font-weight: 700; color: var(--suave); border-radius: 12px; }
.pestanas a i { font-size: 22px; }
.pestanas a.activa { color: var(--acento); background: color-mix(in srgb, var(--acento) 12%, transparent); }
@media (min-width: 760px) {
  .cab { display: flex; align-items: center; justify-content: space-between; padding: 0 20px; }
  .marca { display: flex; align-items: center; gap: 10px; text-decoration: none; font-weight: 800; font-size: 18px; }
  .pestanas { margin: 0; gap: 4px; }
  .pestanas a { flex-direction: row; gap: 8px; font-size: 14px; padding: 10px 14px; }
  .pestanas a i { font-size: 18px; }
}
.lim-ico { font-family: 'Cambria Math', Cambria, serif; font-style: italic; font-weight: 700; background: var(--acento); color: #fff; padding: 2px 8px; border-radius: 8px; }

/* ---------- Estructura ---------- */
.vista { max-width: 760px; margin: 0 auto; padding: 18px 16px 90px; }
h1 { font-size: 30px; line-height: 1.12; letter-spacing: -0.02em; margin: 6px 0 6px; }
h2 { font-size: 20px; margin: 26px 0 10px; letter-spacing: -0.01em; }
h3 { font-size: 13px; text-transform: uppercase; letter-spacing: 0.07em; color: var(--c); margin: 0 0 8px; }
.bajada { color: var(--suave); margin: 0 0 16px; font-size: 16.5px; }
.panel { background: var(--panel); border: 1px solid var(--borde); border-radius: 18px; padding: 16px 18px; margin-bottom: 14px; box-shadow: var(--sombra); }
.entra { animation: entra 0.35s cubic-bezier(0.2, 0.8, 0.2, 1) both; }
@keyframes entra { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { .entra { animation: none; } }

/* ---------- Inicio ---------- */
.metodo { counter-reset: paso; display: grid; gap: 8px; }
.metodo div { display: grid; grid-template-columns: auto 1fr; gap: 2px 12px; align-items: start; }
.metodo b { grid-row: span 2; width: 34px; height: 34px; border-radius: 50%; background: var(--acento); color: #fff; display: grid; place-items: center; font-size: 15px; }
.metodo strong { font-size: 16px; }
.metodo span { color: var(--suave); font-size: 14.5px; }
.atajos { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin: 16px 0; }
.atajo { display: flex; flex-direction: column; gap: 6px; padding: 16px; border-radius: 18px; background: var(--panel); border: 1px solid var(--borde); text-decoration: none; box-shadow: var(--sombra); transition: transform 0.15s; }
.atajo:active { transform: scale(0.98); }
.atajo i { font-size: 28px; color: var(--c, var(--acento)); }
.atajo b { font-size: 16px; }
.atajo span { font-size: 13px; color: var(--suave); }
.tipos { display: grid; gap: 10px; }
.tipo-fila { display: grid; grid-template-columns: auto 1fr auto; gap: 12px; align-items: center; padding: 12px 14px; border-radius: 16px; background: var(--panel); border: 1px solid var(--borde); text-decoration: none; }
.tipo-fila .ico { width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; font-size: 22px; color: #fff; background: var(--c); }
.tipo-fila b { display: block; font-size: 15.5px; }
.tipo-fila small { color: var(--suave); font-size: 13px; }
.barra { height: 6px; border-radius: 3px; background: var(--panel-2); margin-top: 6px; overflow: hidden; }
.barra i { display: block; height: 100%; background: var(--c); border-radius: 3px; }
.pct { font-weight: 800; font-size: 13px; color: var(--suave); }

/* ---------- Árbol ---------- */
.inicio-arbol { text-align: center; padding: 14px; border-radius: 16px; background: var(--acento); color: #fff; font-weight: 800; font-size: 18px; }
.flecha-abajo { text-align: center; color: var(--suave); font-size: 22px; line-height: 1; margin: 6px 0; }
.rama { display: grid; grid-template-columns: 1fr auto; gap: 4px 10px; align-items: center; padding: 12px 14px; border-radius: 16px; border: 1px solid var(--borde); border-left: 6px solid var(--c); background: var(--panel); margin-bottom: 8px; text-decoration: none; }
.rama .si { font-size: 14px; color: var(--suave); font-weight: 700; }
.rama .haz { font-size: 16px; font-weight: 800; }
.rama i { grid-row: span 2; font-size: 20px; color: var(--c); }

/* ---------- Tipo ---------- */
.cab-tipo { display: flex; align-items: center; gap: 12px; }
.cab-tipo .ico { width: 54px; height: 54px; border-radius: 16px; display: grid; place-items: center; font-size: 28px; color: #fff; background: var(--c); flex: none; }
.cuando { border-left: 4px solid var(--c); padding: 10px 14px; background: color-mix(in srgb, var(--c) 10%, var(--panel)); border-radius: 0 14px 14px 0; font-weight: 700; margin: 12px 0 14px; }
.lista { margin: 0; padding-left: 20px; display: grid; gap: 6px; }
.receta { margin: 0; padding: 0; list-style: none; counter-reset: r; display: grid; gap: 8px; }
.receta li { counter-increment: r; display: grid; grid-template-columns: 28px 1fr; gap: 10px; align-items: start; }
.receta li::before { content: counter(r); width: 28px; height: 28px; border-radius: 50%; background: var(--c); color: #fff; font-weight: 800; display: grid; place-items: center; font-size: 14px; }
.ejemplo { border: 1px solid var(--borde); border-radius: 16px; padding: 12px 14px; margin-top: 10px; background: var(--panel-2); }
.enunciado { font-size: 1.15em; text-align: center; }
.paso { display: none; padding: 8px 0; border-top: 1px dashed var(--borde); }
.paso.ver { display: block; animation: entra 0.3s both; }
.paso p { margin: 0 0 2px; font-weight: 600; font-size: 14.5px; }
.respuesta { display: none; margin-top: 8px; padding: 10px 12px; border-radius: 12px; background: color-mix(in srgb, var(--ok) 14%, transparent); font-weight: 800; text-align: center; }
.respuesta.ver { display: block; animation: entra 0.3s both; }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 16px; border-radius: 14px; border: 1px solid var(--borde); background: var(--panel); font-weight: 800; font-size: 15px; text-decoration: none; min-height: 46px; }
.btn.primario { background: var(--c, var(--acento)); border-color: transparent; color: #fff; }
.btn.ancho { width: 100%; margin-top: 10px; }
.btns { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }
.btns .btn { flex: 1; }
.video { display: flex; align-items: center; gap: 10px; padding: 10px 12px; border-radius: 12px; background: var(--panel-2); text-decoration: none; margin-top: 8px; font-weight: 700; font-size: 14.5px; }
.video i { font-size: 26px; color: #FF3B3B; }
.trampa { display: flex; gap: 10px; padding: 8px 0; border-top: 1px solid var(--borde); }
.trampa:first-of-type { border-top: 0; }
.trampa i { color: var(--mal); font-size: 20px; flex: none; margin-top: 2px; }

/* ---------- Ejercicio / entrenador ---------- */
.ejercicio { text-align: center; padding: 22px 14px; }
.ejercicio .enunciado { font-size: 1.35em; }
.etiqueta { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; font-weight: 800; padding: 4px 10px; border-radius: 999px; background: color-mix(in srgb, var(--c) 16%, transparent); color: var(--c); }
.campo { display: flex; gap: 8px; margin-top: 14px; }
.campo input { flex: 1; min-width: 0; font: inherit; font-size: 20px; font-weight: 700; text-align: center; padding: 12px; border-radius: 14px; border: 2px solid var(--borde); background: var(--fondo); color: var(--texto); outline: none; }
.campo input:focus { border-color: var(--c, var(--acento)); }
.teclas { display: flex; gap: 6px; margin-top: 8px; flex-wrap: wrap; justify-content: center; }
.teclas button { padding: 8px 12px; border-radius: 10px; border: 1px solid var(--borde); background: var(--panel-2); font-weight: 800; font-size: 15px; }
.veredicto { margin-top: 12px; padding: 12px; border-radius: 14px; font-weight: 800; display: none; }
.veredicto.ok { display: block; background: color-mix(in srgb, var(--ok) 16%, transparent); color: var(--ok); }
.veredicto.mal { display: block; background: color-mix(in srgb, var(--mal) 14%, transparent); color: var(--mal); }
.solucion { text-align: left; margin-top: 12px; display: none; }
.solucion.ver { display: block; }
.solucion p { margin: 6px 0 2px; font-weight: 600; font-size: 14.5px; }
.marcador { display: flex; justify-content: center; gap: 18px; font-weight: 800; color: var(--suave); font-size: 14px; margin-bottom: 10px; flex-wrap: wrap; }
.marcador b { color: var(--texto); }
.filtro { display: flex; gap: 6px; overflow-x: auto; padding-bottom: 6px; margin-bottom: 10px; scrollbar-width: none; }
.filtro button { flex: none; padding: 8px 12px; border-radius: 999px; border: 1px solid var(--borde); background: var(--panel); font-weight: 700; font-size: 13.5px; }
.filtro button.activo { background: var(--acento); color: #fff; border-color: transparent; }
.opciones { display: grid; gap: 8px; margin-top: 14px; }
.opciones button { padding: 14px; border-radius: 14px; border: 2px solid var(--borde); background: var(--panel); font-weight: 800; font-size: 15.5px; text-align: left; display: flex; gap: 10px; align-items: center; }
.opciones button i { font-size: 22px; color: var(--c); }
.opciones button.bien { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 12%, var(--panel)); }
.opciones button.malo { border-color: var(--mal); background: color-mix(in srgb, var(--mal) 10%, var(--panel)); }
.reloj { font-variant-numeric: tabular-nums; font-weight: 800; font-size: 22px; text-align: center; }
.nota { font-size: 54px; font-weight: 800; text-align: center; color: var(--c); line-height: 1; }
.repaso-item { border-top: 1px solid var(--borde); padding: 10px 0; }
.formula { display: grid; gap: 2px; padding: 10px 0; border-top: 1px solid var(--borde); }
.formula:first-child { border-top: 0; }
.formula b { font-size: 14px; color: var(--suave); }

/* ---------- Desde 0 ---------- */
.banner-cero { display: grid; grid-template-columns: auto 1fr auto; gap: 12px; align-items: center; text-decoration: none; border: 2px solid var(--acento); background: color-mix(in srgb, var(--acento) 10%, var(--panel)); }
.banner-cero > i { font-size: 28px; color: var(--acento); }
.banner-cero b { display: block; font-size: 16.5px; }
.banner-cero small { color: var(--suave); font-size: 13.5px; }
.necesitas { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin: -4px 0 14px; font-size: 13px; }
.necesitas span { font-weight: 800; color: var(--suave); }
.necesitas a { text-decoration: none; padding: 5px 10px; border-radius: 999px; border: 1px solid var(--borde); background: var(--panel); font-weight: 700; }
.necesitas a.hecha { border-color: var(--ok); color: var(--ok); }
.tabla-signos { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; margin-top: 10px; }
.tabla-signos span { padding: 8px; border-radius: 10px; background: var(--panel-2); text-align: center; font-weight: 700; }
.pestanas a span { white-space: nowrap; }
@media (max-width: 420px) { .pestanas a { font-size: 10.5px; } .pestanas a i { font-size: 20px; } }