:root {
  --bg: #f8f9fa;
  --card: #ffffff;
  --text: #1a1a1a;
  --muted: #6c757d;
  --primary: #0d6efd;
  --success: #198754;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  padding: 1rem;
  max-width: 640px;
  margin: 0 auto;
}

header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1.5rem; }
h1 { font-size: 1.5rem; }
#streak { background: #fff3cd; padding: 0.3rem 0.6rem; border-radius: 20px; font-weight: 600; }

.card {
  background: var(--card);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
}
.muted { color: var(--muted); font-size: 0.9rem; }
ul { margin: 0.8rem 0 0 1.2rem; }
li { margin-bottom: 0.4rem; }

.translation {
  color: #0f5132;
  background: #d1e7dd;
  font-weight: 600;
  padding: 0.5rem 0.8rem;
  border-radius: 8px;
  display: inline-block;
  margin-top: 0.5rem;
  font-size: 1.05rem;
}

.btn {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.7rem 1rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  margin-top: 0.5rem;
  transition: opacity 0.2s;
}
.btn:hover { opacity: 0.9; }
.btn:disabled { opacity: 0.6; cursor: not-allowed; }

.option {
  display: block;
  width: 100%;
  text-align: left;
  padding: 0.8rem;
  margin: 0.4rem 0;
  background: #e9ecef;
  border: 2px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.95rem;
}
.option:hover { background: #dee2e6; }
.option.correct { background: #d1e7dd; border-color: var(--success); }
.option.wrong { background: #f8d7da; border-color: #dc3545; }

.hidden { display: none !important; }
#loading { text-align: center; padding: 2rem; color: var(--muted); }
footer { text-align: center; margin-top: 2rem; font-size: 0.8rem; color: var(--muted); }