:root {
  --primary: #2b6cb0;
  --accent: #3182ce;
  --bg: #f7fafc;
  --card-bg: #ffffff;
  --text: #2d3748;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 20px;
}

.container {
  max-width: 800px;
  margin: 0 auto;
}

h1 {
  text-align: center;
  color: var(--primary);
  margin-bottom: 5px;
  font-size: 24px;
}

p.subtitle {
  text-align: center;
  color: #718096;
  margin-bottom: 25px;
}

.quiz-box {
  background: var(--card-bg);
  padding: 25px;
  border-radius: 12px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.08);
  border: 1px solid #e2e8f0;
}

.topic-tag {
  display: inline-block;
  background: #ebf8ff;
  color: #2b6cb0;
  padding: 4px 12px;
  border-radius: 20px;
  font-weight: bold;
  font-size: 13px;
  margin-bottom: 12px;
  text-transform: uppercase;
}

.option-btn {
  display: block;
  width: 100%;
  padding: 14px;
  margin: 10px 0;
  text-align: left;
  background: #f7fafc;
  border: 1.5px solid #cbd5e0;
  border-radius: 8px;
  cursor: pointer;
  transition: 0.2s;
  font-size: 15px;
  color: #2d3748;
}

.option-btn:hover {
  background: #edf2f7;
  border-color: #a0aec0;
}

.option-btn.correct {
  background: #c6f6d5;
  border-color: #38a169;
  color: #22543d;
  font-weight: bold;
}

.option-btn.wrong {
  background: #fed7d7;
  border-color: #e53e3e;
  color: #742a2a;
}

.feedback {
  margin-top: 15px;
  font-size: 14px;
  font-weight: bold;
  line-height: 1.5;
}

.btn {
  padding: 10px 20px;
  border: none;
  border-radius: 6px;
  background: var(--accent);
  color: white;
  cursor: pointer;
  font-weight: bold;
}

.btn:hover {
  opacity: 0.9;
}