:root {
  --bg: #f6f4ef; --card: #ffffff; --ink: #1d2a24; --muted: #66746d; --line: #e2ddd2;
  --brand: #0b5d3b; --brand-ink: #ffffff; --accent: #c8102e;
  --ok: #1f7a46; --ok-bg: #e5f4ea; --casi: #8a5a00; --casi-bg: #fdf1d8; --mal: #b3261e; --mal-bg: #fbe4e2;
  --radius: 14px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1714; --card: #18221e; --ink: #e8efe9; --muted: #9aa8a0; --line: #2a3832;
    --brand: #2fa36b; --brand-ink: #06120c; --accent: #ff5a6e;
    --ok: #6fd39a; --ok-bg: #143022; --casi: #f2c25b; --casi-bg: #33280f; --mal: #ff8a80; --mal-bg: #3a1714;
  }
}
:root[data-theme="dark"] {
  --bg: #0f1714; --card: #18221e; --ink: #e8efe9; --muted: #9aa8a0; --line: #2a3832;
  --brand: #2fa36b; --brand-ink: #06120c; --accent: #ff5a6e;
  --ok: #6fd39a; --ok-bg: #143022; --casi: #f2c25b; --casi-bg: #33280f; --mal: #ff8a80; --mal-bg: #3a1714;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; -webkit-text-size-adjust: 100%; }
.top { position: sticky; top: 0; z-index: 2; display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: calc(env(safe-area-inset-top) + 10px) 16px 10px; background: var(--bg); border-bottom: 1px solid var(--line); }
.top b { color: var(--brand); }
nav { display: flex; gap: 4px; }
nav button { border: 0; background: none; color: var(--muted); font: inherit; font-size: 15px; padding: 6px 10px; border-radius: 999px; cursor: pointer; }
nav button.on { background: var(--brand); color: var(--brand-ink); }
main { max-width: 640px; margin: 0 auto; padding: 16px 16px calc(env(safe-area-inset-bottom) + 40px); }
h1, h2, h3 { line-height: 1.25; margin: 0 0 10px; }
h2 { font-size: 22px; } h3 { font-size: 18px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin-bottom: 14px; }
.aviso { border-color: var(--casi); background: var(--casi-bg); }
.muted { color: var(--muted); } .small { font-size: 14px; }
.row { display: flex; gap: 8px; flex-wrap: wrap; margin: 10px 0; }
.btn { appearance: none; border: 1px solid var(--line); background: var(--card); color: var(--ink); font: inherit; font-weight: 600;
  padding: 12px 18px; border-radius: 12px; cursor: pointer; min-height: 48px; }
.btn.primary { background: var(--brand); border-color: var(--brand); color: var(--brand-ink); width: 100%; margin-top: 12px; }
.btn.ghost { background: transparent; }
.btn.small { min-height: 38px; padding: 6px 12px; font-size: 15px; }
.btn:disabled { opacity: .55; cursor: default; }
.plan { list-style: none; padding: 0; margin: 0 0 4px; } .plan li { padding: 6px 0; border-bottom: 1px dashed var(--line); }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; text-align: center; }
.stats b { display: block; font-size: 24px; color: var(--brand); } .stats span { font-size: 13px; color: var(--muted); }
.fases { display: flex; gap: 6px; margin-bottom: 10px; flex-wrap: wrap; }
.fases span { font-size: 13px; padding: 3px 10px; border-radius: 999px; background: var(--line); color: var(--muted); }
.fases span.on { background: var(--brand); color: var(--brand-ink); } .fases span.hecha { text-decoration: line-through; }
.etiqueta { font-size: 13px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); margin: 0; }
.prompt { font-size: 22px; font-weight: 600; margin: 6px 0 4px; overflow-wrap: anywhere; }
.resp { width: 100%; font: inherit; font-size: 19px; padding: 12px; border-radius: 12px; border: 1px solid var(--line); background: var(--bg); color: var(--ink); margin-top: 10px; }
.opciones { display: grid; gap: 8px; margin-top: 10px; } .opcion { text-align: left; } .opcion.elegida { outline: 2px solid var(--brand); }
.linea, .fichas { display: flex; flex-wrap: wrap; gap: 6px; min-height: 48px; padding: 8px; border-radius: 12px; margin-top: 10px; }
.linea { border: 1px dashed var(--line); } .ficha { min-height: 40px; padding: 6px 12px; }
.fb { margin-top: 12px; padding: 12px; border-radius: 12px; } .fb p { margin: 6px 0; }
.fb.ok { background: var(--ok-bg); color: var(--ok); } .fb.casi { background: var(--casi-bg); color: var(--casi); } .fb.mal { background: var(--mal-bg); color: var(--mal); }
.fb .btn.primary { margin-top: 8px; }
.audio { border: 0; background: none; font-size: 22px; cursor: pointer; padding: 4px; }
.items { list-style: none; padding: 0; margin: 0; }
.items li { display: flex; gap: 10px; align-items: flex-start; padding: 8px 0; border-bottom: 1px solid var(--line); }
.items li div { display: flex; flex-direction: column; } .items span { color: var(--muted); } .items small { color: var(--muted); font-size: 13px; }
.tag { font-size: 12px; font-style: normal; color: var(--accent); }
.leccion table { width: 100%; border-collapse: collapse; margin: 8px 0; font-size: 15px; display: block; overflow-x: auto; }
.leccion th, .leccion td { border: 1px solid var(--line); padding: 6px 8px; text-align: left; }
.grande { font-size: 30px; font-weight: 700; margin: 6px 0; color: var(--brand); }
.fallos { padding-left: 18px; } .fallos li { margin: 4px 0; }
.unidad summary { cursor: pointer; display: flex; flex-wrap: wrap; gap: 6px 8px; align-items: baseline; font-weight: 600; }
.unidad summary small { width: 100%; font-weight: 400; color: var(--muted); } .unidad.bloq { opacity: .6; }
.nivel { font-size: 12px; padding: 1px 8px; border-radius: 999px; background: var(--brand); color: var(--brand-ink); }
.unidad ul { padding-left: 18px; } .unidad li { margin: 6px 0; }
.code { width: 100%; font: 600 22px/1.2 ui-monospace, Menlo, monospace; letter-spacing: .08em; text-align: center; padding: 12px; border-radius: 12px; border: 1px solid var(--line); background: var(--bg); color: var(--ink); }
#toast { position: fixed; left: 50%; bottom: calc(env(safe-area-inset-bottom) + 24px); transform: translate(-50%, 20px); opacity: 0; transition: .25s;
  background: var(--ink); color: var(--bg); padding: 10px 16px; border-radius: 999px; font-size: 15px; pointer-events: none; max-width: calc(100% - 32px); }
#toast.on { opacity: 1; transform: translate(-50%, 0); }