:root {
  --primary-color: #4a90e2;
  --success-color: #2ecc71;
  --error-color: #e74c3c;
  --text-color: #333;
  --bg-color: #f5f7fa;
  --card-bg: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.container {
  width: 90%;
  max-width: 600px;
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 12px;
}

.header {
  text-align: right;
  font-size: 1rem;
  color: #666;
  margin-bottom: 1rem;
}

.question {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  line-height: 1.4;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.option-btn {
  padding: 1rem;
  border: 2px solid #eee;
  border-radius: 8px;
  background: none;
  cursor: pointer;
  text-align: left;
  font-size: 1rem;
  transition: all 0.2s;
}

.option-btn:hover:not(:disabled) {
  border-color: var(--primary-color);
  background-color: #f0f7ff;
}

.option-btn.correct {
  background-color: var(--success-color);
  color: white;
  border-color: var(--success-color);
}

.option-btn.wrong {
  background-color: var(--error-color);
  color: white;
  border-color: var(--error-color);
}

.explanation {
  margin-top: 1.5rem;
  padding: 1rem;
  background-color: #fff4e5;
  border-left: 4px solid #ffa94d;
  border-radius: 4px;
  font-size: 0.95rem;
}

.navigation {
  margin-top: 2rem;
  display: flex;
  justify-content: space-between;
}

button:not(.option-btn) {
  padding: 0.6rem 1.2rem;
  border: 2px solid white;
  border-radius: 6px;
  background-color: var(--primary-color);
  color: white;
  cursor: pointer;
  font-size: 1rem;
}

button:disabled {
  background-color: #ccc;
  border: 2px solid #ccc;
  cursor: not-allowed;
}

.hidden {
  display: none;
}

code,
pre {
  background: #00000011;
  border-radius: 4px;
  font-family: monospace;
}

code {
  padding: 0.2rem 0.4rem;
}

pre {
  padding: 0.8rem;
  white-space: pre-wrap;
  margin: 0.8rem 0;
  overflow-x: auto;
}

/* Mobile adjustments */
@media (max-width: 480px) {
  .container {
    padding: 1rem;
    width: 95%;
  }
  .question {
    font-size: 1rem;
  }
}