:root {
  --bg: #0f1a2b;
  --surface: #17263c;
  --text: #eef3fa;
  --muted: #9fb2cc;
  --accent: #ffb74d;
  --ok: #66bb6a;
  --bad: #ef5350;
  color-scheme: dark;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  padding: 1rem 1.5rem;
  background: var(--surface);
}

.brand {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--accent);
  text-decoration: none;
}

main {
  flex: 1;
  width: 100%;
  max-width: 34rem;
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
  line-height: 1.6;
}

.muted { color: var(--muted); }
.progress { color: var(--muted); font-size: 0.9rem; }

.prompt {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin: 1.5rem 0;
}

form { display: flex; gap: 0.75rem; justify-content: center; }

input[type="text"] {
  font-size: 1.4rem;
  width: 8rem;
  text-align: center;
  padding: 0.5rem;
  border-radius: 0.5rem;
  border: 1px solid var(--muted);
  background: var(--surface);
  color: var(--text);
}

button {
  font-size: 1.05rem;
  padding: 0.55rem 1.4rem;
  border: none;
  border-radius: 0.5rem;
  background: var(--accent);
  color: #1a1205;
  font-weight: 600;
  cursor: pointer;
}
button:hover { filter: brightness(1.1); }

.choices { display: flex; gap: 0.75rem; justify-content: center; flex-wrap: wrap; }
.choice { background: var(--surface); color: var(--text); border: 1px solid var(--muted); }

#feedback { text-align: center; font-size: 1.15rem; min-height: 1.6em; }
.ok { color: var(--ok); }
.bad { color: var(--bad); }

footer {
  padding: 1rem 1.5rem;
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
}