/* Una hoja de respuestas en una sola columna: enunciados en la serif de las revistas científicas,
   alternativas como burbujas que se rellenan con grafito y tres pelotitas para la dificultad. */
:root {
  /* Color */
  --paper: #F5F6F8;
  --sheet: #FFFFFF;
  --ink: #151922;
  --muted: #5A6170;
  --rule: #DADDE3;
  --rule-strong: #B7BECA;
  --graphite: #2B303B;
  --on-graphite: #FFFFFF;
  --easy: #1E9A55;
  --medium: #E2A400;
  --hard: #D33F3F;
  --dot-ring: rgb(21 25 34 / 0.14);
  --ok: #1E9A55;
  --ok-ink: #157A41;
  --ok-tint: #E6F4EC;
  --bad: #CC3B3B;
  --bad-ink: #B32F2F;
  --bad-tint: #FBEAEA;
  --lift: 0 1px 2px rgb(21 25 34 / 0.06);
  --toast-shadow: 0 8px 28px rgb(21 25 34 / 0.22);

  /* Tipografía: serif para el material de la pregunta, sans para la interfaz, mono para datos */
  --font-serif: "STIX Two Text", "STIX Two", Georgia, "Times New Roman", serif;
  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --step--1: 0.8125rem;
  --step-0: 1rem;
  --step-1: 1.125rem;
  --step-2: 1.375rem;
  --step-3: clamp(1.75rem, 1.35rem + 1.8vw, 2.375rem);
  --step-4: clamp(3rem, 2.3rem + 3.2vw, 4.25rem);

  --radius: 8px;
  color-scheme: light;
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0F1116;
    --sheet: #171A21;
    --ink: #E7E9EE;
    --muted: #9AA2B1;
    --rule: #2A2F3A;
    --rule-strong: #424A59;
    --graphite: #E7E9EE;
    --on-graphite: #0F1116;
    --easy: #3BC27A;
    --medium: #F2C232;
    --hard: #F06666;
    --dot-ring: rgb(0 0 0 / 0.35);
    --ok: #3BC27A;
    --ok-ink: #6BD99D;
    --ok-tint: #11281B;
    --bad: #F06666;
    --bad-ink: #FF9090;
    --bad-tint: #2D1518;
    --lift: none;
    --toast-shadow: 0 8px 28px rgb(0 0 0 / 0.5);
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --paper: #0F1116;
  --sheet: #171A21;
  --ink: #E7E9EE;
  --muted: #9AA2B1;
  --rule: #2A2F3A;
  --rule-strong: #424A59;
  --graphite: #E7E9EE;
  --on-graphite: #0F1116;
  --easy: #3BC27A;
  --medium: #F2C232;
  --hard: #F06666;
  --dot-ring: rgb(0 0 0 / 0.35);
  --ok: #3BC27A;
  --ok-ink: #6BD99D;
  --ok-tint: #11281B;
  --bad: #F06666;
  --bad-ink: #FF9090;
  --bad-tint: #2D1518;
  --lift: none;
  --toast-shadow: 0 8px 28px rgb(0 0 0 / 0.5);
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 var(--step-0)/1.55 var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; }
a { color: var(--ink); text-underline-offset: 3px; }
button, input, textarea { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }
[tabindex="-1"]:focus { outline: none; }
code { font-family: var(--font-mono); font-size: 0.9em; }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* Página */
.wrap {
  max-width: 44rem;
  margin-inline: auto;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
  padding-block: 20px 40px;
  display: flex;
  flex-direction: column;
  gap: 2.25rem;
}

main { flex: 1; min-width: 0; }
.screen { display: grid; gap: 2rem; min-width: 0; }
.status { margin: 0; color: var(--muted); }

.masthead {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  min-height: 44px;
  text-decoration: none;
  font: 500 0.9375rem/1 var(--font-mono);
  letter-spacing: 0.02em;
}

.mark { display: inline-flex; gap: 4px; }
.brand-row { display: flex; align-items: center; gap: 0.625rem; }
.badge {
  padding: 0.25rem 0.45rem;
  border: 1px solid var(--rule-strong);
  border-radius: 4px;
  color: var(--muted);
  font: 500 0.6875rem/1 var(--font-mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.masthead-side { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem 1rem; }
.bank-size { font: 400 var(--step--1)/1.2 var(--font-mono); color: var(--muted); }

/* Selector de idioma */
.lang { display: inline-flex; border: 1px solid var(--rule-strong); border-radius: 6px; overflow: hidden; }
.lang button {
  min-width: 2.75rem;
  min-height: 36px;
  padding: 0 0.6rem;
  border: 0;
  background: var(--sheet);
  color: var(--muted);
  font: 500 0.8125rem/1 var(--font-mono);
  cursor: pointer;
}
.lang button + button { border-left: 1px solid var(--rule-strong); }
.lang button:hover { color: var(--ink); }
.lang button[aria-pressed="true"] { background: var(--graphite); color: var(--on-graphite); }

/* Pelotitas de dificultad */
.dot {
  display: inline-block;
  flex: none;
  width: 0.625rem;
  height: 0.625rem;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1px var(--dot-ring);
}
.mark .dot { width: 0.75rem; height: 0.75rem; }
.dot.easy { background: var(--easy); }
.dot.medium { background: var(--medium); }
.dot.hard { background: var(--hard); }

/* Textos de apoyo */
.label {
  margin: 0;
  font: 500 0.75rem/1.2 var(--font-mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.hint { margin: 0; font-size: 0.875rem; color: var(--muted); }

/* Botones */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 44px;
  padding: 0.625rem 1.125rem;
  border: 1px solid var(--rule-strong);
  border-radius: 6px;
  background: var(--sheet);
  color: var(--ink);
  font: 500 var(--step-0)/1.2 var(--font-sans);
  text-decoration: none;
  cursor: pointer;
}
.btn:hover { border-color: var(--ink); }
.btn.primary { background: var(--graphite); border-color: var(--graphite); color: var(--on-graphite); }
.btn.primary:hover { background: color-mix(in srgb, var(--graphite) 86%, var(--paper)); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.linkish {
  min-height: 44px;
  padding: 0;
  border: 0;
  background: none;
  color: var(--muted);
  font: 400 0.9375rem/1.2 var(--font-sans);
  text-decoration: underline;
  text-underline-offset: 3px;
  cursor: pointer;
}
.linkish:hover { color: var(--ink); }

.actions { display: flex; flex-wrap: wrap; gap: 0.625rem; }

/* Inicio */
.intro { display: grid; gap: 0.75rem; }
.intro h1 {
  margin: 0;
  font: 400 var(--step-3)/1.15 var(--font-serif);
  letter-spacing: -0.01em;
  text-wrap: balance;
  /* Ancho tope para que el titular corte en dos líneas en inglés y en español. */
  max-width: 15em;
}
/* El texto del objetivo va en letra chica, debajo del titular. */
.intro p { margin: 0; max-width: 36rem; font-size: 0.875rem; color: var(--muted); }

.resume {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1rem;
  padding: 0.875rem 1rem;
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  background: var(--sheet);
}
.resume p { margin: 0; flex: 1 1 16rem; }

.setup { display: grid; gap: 1.75rem; }
.field { display: grid; gap: 0.75rem; min-width: 0; }
.field-head { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.field-head .label { line-height: 44px; }
.field-actions { display: flex; gap: 1rem; }

.chips { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  min-height: 40px;
  padding: 0.4rem 0.85rem 0.4rem 0.7rem;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: var(--sheet);
  color: var(--muted);
  font: 400 0.9375rem/1.2 var(--font-sans);
  text-align: left;
  cursor: pointer;
}
.chip:hover { border-color: var(--rule-strong); color: var(--ink); }
.chip .count {
  font: 400 var(--step--1)/1 var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}
.chip[aria-pressed="true"] { border-color: var(--graphite); color: var(--ink); }
.chip[aria-pressed="false"] .dot { opacity: 0.3; }

/* Burbuja de hoja de respuestas: vacía si el área está fuera, rellena si está dentro */
.tick {
  flex: none;
  width: 0.75rem;
  height: 0.75rem;
  border: 1.5px solid var(--rule-strong);
  border-radius: 50%;
}
.chip[aria-pressed="true"] .tick { background: var(--graphite); border-color: var(--graphite); }

.counts { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.count-opt {
  min-width: 3.25rem;
  min-height: 40px;
  padding: 0.4rem 0.8rem;
  border: 1px solid var(--rule-strong);
  border-radius: 6px;
  background: var(--sheet);
  font: 500 0.9375rem/1 var(--font-mono);
  font-variant-numeric: tabular-nums;
  cursor: pointer;
}
.count-opt:hover:not(:disabled) { border-color: var(--ink); }
.count-opt[aria-pressed="true"] { background: var(--graphite); border-color: var(--graphite); color: var(--on-graphite); }
.count-opt:disabled { opacity: 0.35; cursor: not-allowed; }

.modes { display: grid; grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr)); gap: 0.5rem; }
.mode {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.875rem 1rem;
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  background: var(--sheet);
  cursor: pointer;
}
.mode:has(input:checked) { border-color: var(--graphite); box-shadow: inset 0 0 0 1px var(--graphite); }
.mode input { flex: none; width: 1.05rem; height: 1.05rem; margin: 0.2rem 0 0; accent-color: var(--graphite); }
.mode b { display: block; font-weight: 600; }
.mode small { display: block; font-size: 0.875rem; line-height: 1.4; color: var(--muted); }

.start-row { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem 1.25rem; }
.start-row .btn { min-width: 9rem; }
.available { font: 400 0.875rem/1.3 var(--font-mono); color: var(--muted); }

/* Pregunta */
.quiz-head { display: grid; gap: 0.25rem; }
.quiz-top { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.progress-label {
  font: 500 0.875rem/1 var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}
.progress { height: 3px; border-radius: 2px; background: var(--rule); overflow: hidden; }
.progress span { display: block; width: 0; height: 100%; background: var(--graphite); transition: width 200ms ease; }

.question { display: grid; gap: 1.25rem; min-width: 0; }
.q-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.25rem 0.625rem;
  font-size: 0.875rem;
  line-height: 1.35;
  color: var(--muted);
}
.level-tag { display: inline-flex; align-items: center; gap: 0.4rem; font-weight: 600; color: var(--ink); }
.q-topic { min-width: 0; }

.q-prompt {
  margin: 0;
  font: 400 var(--step-2)/1.38 var(--font-serif);
  text-wrap: pretty;
}
.q-prompt:focus { outline: none; }
.q-code {
  margin: 0;
  padding: 0.875rem 1rem;
  overflow-x: auto;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--sheet);
  font: 400 0.875rem/1.5 var(--font-mono);
}

.options { display: grid; gap: 0.625rem; margin: 0; padding: 0; list-style: none; }
.option {
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  align-items: start;
  gap: 0.875rem;
  width: 100%;
  padding: 0.875rem 1rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--sheet);
  box-shadow: var(--lift);
  color: var(--ink);
  font: 400 var(--step-1)/1.45 var(--font-serif);
  text-align: left;
  cursor: pointer;
}
.option:hover:not(:disabled) { border-color: var(--rule-strong); }
.option:disabled { cursor: default; }
.option-text { min-width: 0; overflow-wrap: break-word; }

.bubble {
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  margin-top: -0.1rem;
  border: 1.5px solid var(--rule-strong);
  border-radius: 50%;
  color: var(--muted);
  font: 500 0.875rem/1 var(--font-mono);
  transition: background-color 120ms ease, border-color 120ms ease, color 120ms ease;
}
.option[aria-pressed="true"] { border-color: var(--graphite); }
.option[aria-pressed="true"] .bubble { background: var(--graphite); border-color: var(--graphite); color: var(--on-graphite); }
.option.is-correct { border-color: var(--ok); background: var(--ok-tint); }
.option.is-correct .bubble { background: var(--ok); border-color: var(--ok); color: var(--on-graphite); }
.option.is-wrong { border-color: var(--bad); background: var(--bad-tint); }
.option.is-wrong .bubble { background: var(--bad); border-color: var(--bad); color: var(--on-graphite); }

.rationale {
  margin: 0.4rem 0 0.25rem;
  padding-inline: calc(1rem + 2rem + 0.875rem + 1px) 1rem;
  font-size: 0.9375rem;
  line-height: 1.5;
  color: var(--muted);
}

.feedback { display: grid; gap: 1rem; padding-top: 1.25rem; border-top: 1px solid var(--rule); }
.feedback .block { display: grid; gap: 0.4rem; }
.feedback p { margin: 0; }
.verdict { font: 600 var(--step-1)/1.3 var(--font-sans); }
.verdict.ok { color: var(--ok-ink); }
.verdict.bad { color: var(--bad-ink); }

.sources { display: grid; gap: 0.4rem; margin: 0; padding: 0; list-style: none; font-size: 0.9375rem; }
.sources .kind {
  margin-right: 0.5rem;
  font: 500 0.6875rem/1 var(--font-mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.q-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.375rem 1rem;
  font: 400 var(--step--1)/1.4 var(--font-mono);
  color: var(--muted);
}
.q-foot a { color: var(--muted); }

.quiz-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem 1rem; }
.quiz-actions .btn { margin-left: auto; min-width: 9rem; }
.keys { display: none; font: 400 var(--step--1)/1.3 var(--font-mono); color: var(--muted); }
@media (hover: hover) and (pointer: fine) { .keys { display: inline; } }
@media (max-width: 30rem) { .quiz-actions .btn { width: 100%; } }

/* Resultado */
.results { display: grid; gap: 2.25rem; }
.score { margin: 0.5rem 0 0; font: 600 var(--step-4)/1 var(--font-serif); font-variant-numeric: lining-nums tabular-nums; }
.score small { margin-left: 0.35rem; font: 400 var(--step-2)/1 var(--font-serif); color: var(--muted); }
.score-sub { margin: 0.625rem 0 0; font: 400 0.9375rem/1.3 var(--font-mono); color: var(--muted); }

.panel { display: grid; gap: 0.875rem; min-width: 0; }
.bars { display: grid; gap: 0.625rem; }
.bar-row {
  display: grid;
  grid-template-columns: minmax(6rem, 15rem) minmax(0, 1fr) 3.5rem;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.9375rem;
}
.bar-row .name { display: inline-flex; align-items: center; gap: 0.5rem; min-width: 0; overflow-wrap: anywhere; }
.bar { height: 6px; border-radius: 3px; background: var(--rule); overflow: hidden; }
.bar span { display: block; height: 100%; background: var(--graphite); }
.bar.topic span { background: var(--muted); }
.bar.easy span { background: var(--easy); }
.bar.medium span { background: var(--medium); }
.bar.hard span { background: var(--hard); }
.bar-row .val { font: 500 0.875rem/1 var(--font-mono); font-variant-numeric: tabular-nums; text-align: right; }

@media (max-width: 30rem) {
  .bar-row { grid-template-columns: minmax(0, 1fr) 3.5rem; row-gap: 0.4rem; }
  .bar-row .bar { grid-column: 1 / -1; grid-row: 2; }
}

.topics summary {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 44px;
  list-style: none;
  cursor: pointer;
}
.topics summary::-webkit-details-marker { display: none; }
.topics summary::after {
  content: "+";
  margin-left: auto;
  font: 500 1.125rem/1 var(--font-mono);
  color: var(--muted);
}
.topics[open] summary::after { content: "−"; }
.topics .bars { margin-top: 0.5rem; }

.share textarea {
  width: 100%;
  min-height: 8.5rem;
  padding: 0.875rem 1rem;
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  background: var(--sheet);
  font: 400 0.9375rem/1.55 var(--font-sans);
  resize: vertical;
}

.card-preview {
  display: grid;
  max-width: 28rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--sheet);
  overflow: hidden;
}
.card-preview img { display: block; width: 100%; height: auto; aspect-ratio: 1200 / 627; background: var(--paper); }
.card-preview div { display: grid; gap: 0.25rem; padding: 0.75rem 1rem; border-top: 1px solid var(--rule); }
.card-preview .domain { font: 400 0.75rem/1.2 var(--font-mono); color: var(--muted); }
.card-preview .title { font: 600 0.9375rem/1.3 var(--font-sans); }

.support {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1rem;
  padding: 1rem 1.125rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--sheet);
}
.support p { margin: 0; flex: 1 1 16rem; }

.review { gap: 0.5rem; }
.review .label { margin-bottom: 0.375rem; }
.review details { border: 1px solid var(--rule); border-radius: var(--radius); background: var(--sheet); }
.review summary {
  display: grid;
  grid-template-columns: 1.5rem minmax(0, 1fr);
  align-items: start;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  font: 400 var(--step-0)/1.45 var(--font-serif);
  list-style: none;
  cursor: pointer;
}
.review summary::-webkit-details-marker { display: none; }
.mini {
  display: grid;
  place-items: center;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  color: var(--on-graphite);
  font: 600 0.75rem/1 var(--font-sans);
}
.mini.ok { background: var(--ok); }
.mini.bad { background: var(--bad); }
.review .body {
  display: grid;
  gap: 0.5rem;
  padding: 0 1rem 1rem calc(1rem + 1.5rem + 0.75rem);
  font-size: 0.9375rem;
}
.review .body p { margin: 0; }

/* Pie y avisos */
.foot {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  font: 400 var(--step--1)/1.4 var(--font-mono);
  color: var(--muted);
}
.foot a { color: var(--muted); }

.toast {
  position: fixed;
  left: 50%;
  bottom: calc(16px + env(safe-area-inset-bottom, 0px));
  z-index: 20;
  max-width: calc(100% - 32px);
  padding: 0.75rem 1rem;
  border-radius: 6px;
  background: var(--graphite);
  color: var(--on-graphite);
  box-shadow: var(--toast-shadow);
  font: 500 0.9375rem/1.35 var(--font-sans);
  transform: translateX(-50%);
}

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