:root {
  --bg: #F4F6FB; --surface: #FFFFFF; --ink: #1E2A44; --muted: #5C6879;
  --border: #E1E7F0; --field: #FFFFFF; --field-border: #CFDAEA;
  --primary: #3B7DD8; --on-primary: #FFFFFF; --secondary-bg: #E7F0FC;
  --ok: #15804A; --warn: #9A6613; --bad: #BE3350; --track: #DCE4F0;
}

* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: 'Segoe UI', system-ui, sans-serif; font-size: 15px;
}
[hidden] { display: none !important; }

#topbar {
  display: flex; align-items: center; gap: 12px; padding: 10px 20px;
  background: var(--surface); border-bottom: 1px solid var(--border);
}
#topbar .brand { font-weight: 800; font-size: 18px; }
#topbar .stat {
  background: var(--secondary-bg); border-radius: 12px; padding: 6px 14px; font-weight: 700;
}
#topbar .spacer { flex: 1; }
#topbar select { padding: 6px 8px; border-radius: 8px; border: 1px solid var(--field-border); }

main { max-width: 720px; margin: 0 auto; padding: 24px 18px 60px; }

h1 { font-size: 24px; margin: 0 0 4px; }
.subtitle { color: var(--muted); margin: 0 0 20px; }

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

label { display: block; font-weight: 600; margin: 12px 0 4px; }
input[type=text], input[type=email], input[type=password] {
  width: 100%; padding: 10px 12px; border: 2px solid var(--field-border);
  border-radius: 9px; font-size: 15px; background: var(--field); color: var(--ink);
}
input:focus { outline: none; border-color: var(--primary); }

button {
  background: var(--primary); color: var(--on-primary); border: 0; border-radius: 9px;
  padding: 10px 18px; font-weight: 700; font-size: 14px; cursor: pointer;
}
button:hover { filter: brightness(1.05); }
button:disabled { background: var(--track); color: var(--muted); cursor: not-allowed; }
button.secondary { background: var(--secondary-bg); color: var(--primary); }
button.link { background: transparent; color: var(--primary); padding: 4px; font-weight: 600; }

.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.error { color: var(--bad); font-weight: 600; margin-top: 8px; }
.hint { color: var(--muted); font-size: 13px; }

/* --- mapa --- */
.unit { margin-bottom: 22px; }
.unit-title { font-weight: 800; margin-bottom: 8px; }
.unit-title .done { color: var(--ok); }
.nodes { display: flex; flex-wrap: wrap; gap: 10px; }
.node {
  width: 78px; display: flex; flex-direction: column; align-items: center; gap: 4px;
  background: none; border: 0; padding: 0; cursor: pointer; color: var(--ink);
}
.node .dot {
  width: 56px; height: 56px; border-radius: 50%; display: flex; align-items: center;
  justify-content: center; font-size: 22px; font-weight: 800;
}
.node[data-state=done] .dot { background: var(--ok); color: #fff; }
.node[data-state=current] .dot { background: var(--primary); color: #fff; border: 4px solid var(--warn); }
.node[data-state=open] .dot { background: var(--surface); border: 3px solid var(--primary); }
.node[data-state=locked] .dot { background: var(--track); color: var(--muted); }
.node[data-state=locked] { cursor: default; }
.node .label { font-size: 11px; text-align: center; color: var(--muted); }

/* --- ejercicio --- */
.progress-bar { height: 10px; background: var(--track); border-radius: 6px; overflow: hidden; margin-bottom: 16px; }
.progress-bar > div { height: 100%; background: var(--primary); }
.prompt { font-size: 19px; font-weight: 700; margin-bottom: 14px; }
.options { display: flex; flex-direction: column; gap: 8px; }
.options label {
  display: flex; align-items: center; gap: 8px; font-weight: 500;
  border: 2px solid var(--field-border); border-radius: 9px; padding: 10px 12px; cursor: pointer;
}
.tokens { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.tokens button { background: var(--secondary-bg); color: var(--primary); }
.tokens button:disabled { opacity: .35; }
.chosen-order { min-height: 20px; font-size: 17px; font-weight: 600; margin: 10px 0; }
.match-row { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.match-row span { width: 140px; font-weight: 600; }
.match-row select { flex: 1; padding: 8px; border-radius: 8px; border: 1px solid var(--field-border); }
.feedback { margin-top: 14px; font-weight: 700; white-space: pre-line; }
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--bad); }

/* --- ranking --- */
table { width: 100%; border-collapse: collapse; }
table th, table td { text-align: left; padding: 6px 8px; }
table tr.me { font-weight: 800; background: var(--secondary-bg); }