:root {
  --mark-ok: #16a34a;
  --mark-bad: #dc2626;
  --mark-blank: #d97706;
  --bg: #f6f7f9;
  --card: #ffffff;
  --text: #1a1d23;
  --muted: #5d6573;
  --border: #e2e5ea;
  --primary: #2563eb;
  --primary-text: #ffffff;
  --ok: #15803d;
  --ok-bg: #f0fdf4;
  --bad: #b91c1c;
  --bad-bg: #fef2f2;
  --neutral-bg: #f3f4f6;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --card: #181b21;
    --text: #e6e8ec;
    --muted: #9aa3b2;
    --border: #2a2f38;
    --primary: #3b82f6;
    --ok: #4ade80;
    --ok-bg: #0f2a1a;
    --bad: #f87171;
    --bad-bg: #2c1414;
    --neutral-bg: #22262e;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

.wrap { max-width: 860px; margin: 0 auto; padding: 24px 16px 48px; }

.brand { display: flex; align-items: baseline; gap: 10px; margin-bottom: 20px; }
.logo { font-weight: 800; font-size: 1.4rem; letter-spacing: -0.02em; }
.brand-sub { color: var(--muted); font-size: 0.95rem; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 16px;
}

h1 { font-size: 1.3rem; margin: 0 0 6px; }
h2 { font-size: 1.05rem; margin: 0 0 12px; }

.muted { color: var(--muted); }
.small { font-size: 0.85rem; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }

#login { max-width: 420px; }
#login .muted { margin: 0 0 16px; }

label { display: block; font-weight: 600; font-size: 0.9rem; margin: 12px 0 4px; }

input {
  width: 100%;
  padding: 10px 12px;
  font: inherit;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.04em;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
}
input:focus { outline: 2px solid var(--primary); outline-offset: 1px; }

button {
  margin-top: 18px;
  width: 100%;
  padding: 11px 16px;
  font: inherit;
  font-weight: 600;
  color: var(--primary-text);
  background: var(--primary);
  border: 0;
  border-radius: 8px;
  cursor: pointer;
}
button:disabled { opacity: 0.6; cursor: progress; }
button.secondary {
  width: auto;
  margin: 0;
  color: var(--text);
  background: transparent;
  border: 1px solid var(--border);
}

.error {
  margin: 14px 0 0;
  padding: 10px 12px;
  color: var(--bad);
  background: var(--bad-bg);
  border-radius: 8px;
  font-size: 0.9rem;
}

.result-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.result-head h1 { overflow-wrap: anywhere; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px; margin-top: 16px; }
.stat { background: var(--neutral-bg); border-radius: 10px; padding: 12px; }
.stat-label { display: block; color: var(--muted); font-size: 0.8rem; }
.stat-value { display: block; font-size: 1.5rem; font-weight: 700; }
.stat.ok { background: var(--ok-bg); color: var(--ok); }
.stat.bad { background: var(--bad-bg); color: var(--bad); }

.page { padding: 8px; }
.page img { display: block; width: 100%; height: auto; border-radius: 6px; }
.page figcaption { text-align: center; margin-top: 6px; }
figure { margin: 0 0 16px; }

footer { margin-top: 24px; text-align: center; }

/* ---------- Hoja con marcas ---------- */
.sheet { position: relative; line-height: 0; }
.sheet img { display: block; width: 100%; height: auto; border-radius: 6px; }
.overlay { position: absolute; inset: 0; width: 100%; height: 100%; overflow: visible; }
.overlay .q { cursor: pointer; outline: none; }
.overlay .row-hit { fill: transparent; stroke: none; transition: fill .15s; }
.overlay .q:hover .row-hit, .overlay .q:focus-visible .row-hit { fill: rgba(37, 99, 235, .10); }
.overlay .q.selected .row-hit { fill: rgba(37, 99, 235, .18); stroke: #2563eb; stroke-width: 2; }
svg .mark { stroke-width: 3; }
svg .mark.ok { fill: rgba(22, 163, 74, .35); stroke: var(--mark-ok); }
svg .mark.bad { fill: rgba(220, 38, 38, .35); stroke: var(--mark-bad); }
svg .key-ring { fill: none; stroke: var(--mark-ok); stroke-width: 3; stroke-dasharray: 5 4; }
svg .blank-ring { fill: none; stroke: var(--mark-blank); stroke-width: 2; stroke-dasharray: 6 5; }
svg .annulled-line { stroke: #6b7280; stroke-width: 3; }

.legend { display: flex; flex-wrap: wrap; gap: 6px 16px; margin: 0 4px 10px; font-size: .85rem; color: var(--muted); }
.legend-item { display: inline-flex; align-items: center; gap: 6px; }
.legend-dot { width: 14px; height: 14px; border-radius: 50%; border: 2px solid; display: inline-block; }
.legend-dot.ok { border-color: var(--mark-ok); background: rgba(22, 163, 74, .35); }
.legend-dot.bad { border-color: var(--mark-bad); background: rgba(220, 38, 38, .35); }
.legend-dot.key { border-color: var(--mark-ok); border-style: dashed; }
.legend-dot.blank { border-color: var(--mark-blank); border-style: dashed; border-radius: 4px; }

/* ---------- Resumen por pregunta ---------- */
.chips { display: grid; grid-template-columns: repeat(auto-fill, minmax(42px, 1fr)); gap: 6px; margin-top: 10px; }
.chip {
  margin: 0; width: auto; padding: 8px 0; border-radius: 8px; font-weight: 700; font-size: .9rem;
  color: var(--text); background: var(--neutral-bg); border: 2px solid transparent;
}
.chip.st-correct { color: var(--ok); background: var(--ok-bg); border-color: var(--mark-ok); }
.chip.st-incorrect { color: var(--bad); background: var(--bad-bg); border-color: var(--mark-bad); }
.chip.st-blank { border-color: var(--mark-blank); border-style: dashed; }
.chip.st-annulled { color: var(--muted); text-decoration: line-through; }
.chip.st-development { color: var(--muted); }

/* ---------- Detalle de una pregunta ---------- */
body.pop-open { overflow: hidden; }
.pop { position: fixed; inset: 0; z-index: 50; display: flex; align-items: flex-end; justify-content: center; }
.pop[hidden] { display: none; }
.pop-backdrop { position: absolute; inset: 0; background: rgba(0, 0, 0, .45); }
.pop-card {
  position: relative; width: 100%; max-width: 560px; max-height: 85vh; overflow-y: auto;
  background: var(--card); color: var(--text); border-radius: 16px 16px 0 0; padding: 18px 18px 14px;
  box-shadow: 0 -8px 30px rgba(0, 0, 0, .25);
}
@media (min-width: 700px) {
  .pop { align-items: center; }
  .pop-card { border-radius: 16px; }
}
.pop-head { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.pop-head h2 { margin: 0; flex: 1; }
.icon-btn {
  margin: 0; width: 36px; height: 36px; padding: 0; font-size: 1.5rem; line-height: 1;
  color: var(--text); background: transparent; border: 1px solid var(--border); border-radius: 50%;
}
.status-chip { font-size: .8rem; font-weight: 600; padding: 3px 10px; border-radius: 999px; background: var(--neutral-bg); color: var(--muted); white-space: nowrap; }
.status-chip.st-correct { background: var(--ok-bg); color: var(--ok); }
.status-chip.st-incorrect { background: var(--bad-bg); color: var(--bad); }
.pop-body { line-height: 1.5; }
.row-zoom-wrap { margin: 0 0 12px; border: 1px solid var(--border); border-radius: 10px; overflow: hidden; background: #fff; line-height: 0; }
.row-zoom { display: block; width: 100%; height: auto; }
.q-text { margin: 0 0 12px; font-weight: 500; white-space: pre-wrap; }
.q-points { font-weight: 600; }
.alts { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.alt { display: flex; align-items: flex-start; gap: 10px; padding: 10px; border: 1px solid var(--border); border-radius: 10px; }
.alt-letter {
  flex: none; width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center;
  font-weight: 700; background: var(--neutral-bg);
}
.alt-text { flex: 1; min-width: 0; overflow-wrap: anywhere; }
.alt-tags { display: flex; flex-direction: column; gap: 4px; align-items: flex-end; }
.tag { font-size: .72rem; font-weight: 700; padding: 2px 8px; border-radius: 999px; white-space: nowrap; }
.tag.ok { background: var(--ok-bg); color: var(--ok); }
.tag.bad { background: var(--bad-bg); color: var(--bad); }
.alt.key { border-color: var(--mark-ok); }
.alt.key .alt-letter { background: var(--mark-ok); color: #fff; }
.alt.mine-ok { border-color: var(--mark-ok); background: var(--ok-bg); }
.alt.mine-ok .alt-letter { background: var(--mark-ok); color: #fff; }
.alt.mine-bad { border-color: var(--mark-bad); background: var(--bad-bg); }
.alt.mine-bad .alt-letter { background: var(--mark-bad); color: #fff; }
.answers { display: grid; grid-template-columns: auto 1fr; gap: 6px 14px; margin: 0; }
.answers dt { color: var(--muted); }
.answers dd { margin: 0; font-weight: 600; }
.feedback { margin-top: 14px; padding: 12px; border-radius: 10px; background: var(--neutral-bg); }
.feedback h3 { margin: 0 0 6px; font-size: .9rem; }
.feedback p { margin: 0 0 6px; white-space: pre-wrap; }
.feedback p:last-child { margin-bottom: 0; }
.pop-nav { display: flex; gap: 10px; margin-top: 16px; }
.pop-nav button { flex: 1; margin: 0; }
.pop-nav button:disabled { opacity: .4; cursor: default; }

/* ---------- Página de inicio ---------- */
.home { max-width: 560px; }
.home h1 { font-size: 1.6rem; margin-bottom: 8px; }
.home .lead { margin: 0 0 20px; color: var(--muted); }
.actions { display: grid; gap: 10px; }
.btn {
  display: block;
  padding: 11px 16px;
  text-align: center;
  font-weight: 600;
  text-decoration: none;
  border-radius: 8px;
  color: var(--primary-text);
  background: var(--primary);
}
.btn.secondary { color: var(--text); background: transparent; border: 1px solid var(--border); }
.home ul { margin: 0; padding-left: 20px; }
.home li { margin: 4px 0; }