:root {
  color-scheme: light dark;
  --bg: #fafafa;
  --fg: #1a1a1a;
  --muted: #666;
  --border: #ddd;
  --accent: #2563eb;
  --good: #16a34a;
  --bad: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16181d;
    --fg: #eee;
    --muted: #999;
    --border: #333;
    --accent: #60a5fa;
    --good: #4ade80;
    --bad: #f87171;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--fg);
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

header h1 { font-size: 1.1rem; margin: 0; }

nav { display: flex; gap: 0.5rem; }

.nav-btn {
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--fg);
  border-radius: 6px;
  cursor: pointer;
}

.nav-btn.active {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

main {
  max-width: 480px;
  margin: 0 auto;
  padding: 2rem 1.25rem;
}

.hidden { display: none !important; }

#quiz-card { text-align: center; }

.quiz-meta {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
}

.prompt {
  font-size: 2rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

#quiz-form { display: flex; gap: 0.5rem; }

#quiz-answer {
  flex: 1;
  padding: 0.6rem 0.8rem;
  font-size: 1.1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--fg);
}

button {
  padding: 0.6rem 1rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--accent);
  color: white;
  cursor: pointer;
}

#quiz-form button, #quiz-next-btn {
  background: var(--accent);
}

.feedback {
  margin-top: 1.25rem;
  padding: 0.75rem;
  border-radius: 6px;
  font-size: 1.1rem;
}

.feedback.correct { background: color-mix(in srgb, var(--good) 20%, transparent); color: var(--good); }
.feedback.wrong { background: color-mix(in srgb, var(--bad) 20%, transparent); color: var(--bad); }

#quiz-next-btn { margin-top: 1rem; }

section {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

section h2 { font-size: 1rem; margin-bottom: 0.75rem; }

form { display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; }

input, select {
  padding: 0.5rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--fg);
  font-size: 0.95rem;
}

.deck-row, .word-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.4rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.deck-row:last-child, .word-row:last-child { border-bottom: none; }

.deck-row button, .word-row button {
  background: transparent;
  color: var(--bad);
  border: none;
  padding: 0.2rem 0.5rem;
  font-size: 0.85rem;
}

.msg { font-size: 0.85rem; color: var(--muted); }
.msg.error { color: var(--bad); }
.msg.success { color: var(--good); }

#word-list { max-height: 240px; overflow-y: auto; }