* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 24px 16px;
  color: #2d3748;
}

.container {
  width: 100%;
  max-width: 720px;
}

.header {
  text-align: center;
  margin-top: 16px;
  margin-bottom: 16px;
}

.header h1 {
  font-size: 28px;
  background: linear-gradient(90deg, #4f46e5, #7c3aed);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.subtitle {
  color: #718096;
  margin-top: 6px;
  font-size: 14px;
}

.stats-bar {
  display: flex;
  justify-content: space-around;
  background: #fff;
  border-radius: 12px;
  padding: 12px 0;
  margin-bottom: 12px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.stat-label {
  font-size: 12px;
  color: #a0aec0;
}

.stat-value {
  font-size: 20px;
  font-weight: 700;
}

.stat-value.correct {
  color: #38a169;
}

.stat-value.wrong {
  color: #e53e3e;
}

.mode-bar {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}

.mode-btn {
  flex: 1;
  padding: 10px;
  border: 2px solid #e2e8f0;
  border-radius: 10px;
  background: #fff;
  font-size: 14px;
  font-weight: 600;
  color: #718096;
  cursor: pointer;
  transition: all 0.2s ease;
}

.mode-btn:hover {
  border-color: #a5b4fc;
  color: #4f46e5;
}

.mode-btn.active {
  border-color: #4f46e5;
  background: #eef2ff;
  color: #4f46e5;
}

.wrong-badge {
  display: inline-block;
  margin-left: 6px;
  background: #e53e3e;
  color: #fff;
  font-size: 12px;
  padding: 1px 8px;
  border-radius: 999px;
}

.progress-track {
  height: 6px;
  background: #e2e8f0;
  border-radius: 3px;
  margin-bottom: 24px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #4f46e5, #7c3aed);
  border-radius: 3px;
  transition: width 0.4s ease;
}

.card {
  background: #fff;
  border-radius: 16px;
  padding: 28px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
  min-height: 560px;
  display: flex;
  flex-direction: column;
}

.question-meta {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  background: #eef2ff;
  color: #4f46e5;
}

.badge.category {
  background: #f0fff4;
  color: #38a169;
}

.badge.ok {
  background: #f0fff4;
  color: #38a169;
}

.badge.no {
  background: #fff5f5;
  color: #e53e3e;
}

.question-text {
  font-size: 18px;
  line-height: 1.6;
  margin-bottom: 20px;
  min-height: 58px;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex: 1 1 auto;
  justify-content: flex-start;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  border: 2px solid #e2e8f0;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s ease;
  font-size: 15px;
  line-height: 1.5;
}

.option:hover {
  border-color: #a5b4fc;
  background: #f5f6ff;
}

.option.selected {
  border-color: #4f46e5;
  background: #eef2ff;
}

.option.correct-opt {
  border-color: #38a169;
  background: #f0fff4;
}

.option.wrong-opt {
  border-color: #e53e3e;
  background: #fff5f5;
}

.option.disabled {
  cursor: default;
  opacity: 0.75;
}

.option-key {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 8px;
  background: #edf2f7;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
  color: #4a5568;
}

.option.selected .option-key {
  background: #4f46e5;
  color: #fff;
}

.option.correct-opt .option-key {
  background: #38a169;
  color: #fff;
}

.option.wrong-opt .option-key {
  background: #e53e3e;
  color: #fff;
}

.answer-panel {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.answer-verdict {
  font-size: 16px;
  font-weight: 700;
  text-align: center;
  padding: 10px;
  border-radius: 10px;
}

.answer-verdict.ok {
  background: #f0fff4;
  color: #276749;
  border: 1px solid #c6f6d5;
}

.answer-verdict.no {
  background: #fff5f5;
  color: #742a2a;
  border: 1px solid #fed7d7;
}

.answer-block {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.answer-label {
  align-self: flex-start;
  font-size: 12px;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 999px;
}

.answer-label.ok-label {
  background: #f0fff4;
  color: #276749;
}

.answer-label.no-label {
  background: #fff5f5;
  color: #742a2a;
}

.answer-label.info-label {
  background: #eef2ff;
  color: #3730a3;
}

.answer-content {
  font-size: 15px;
  line-height: 1.7;
  background: #fafafa;
  border: 1px solid #e2e8f0;
  border-radius: 10px;
  padding: 12px 14px;
  color: #2d3748;
}

.feedback {
  margin-top: 20px;
  padding: 16px;
  border-radius: 12px;
  font-size: 14px;
  line-height: 1.7;
}

.feedback.ok {
  background: #f0fff4;
  border: 1px solid #c6f6d5;
  color: #22543d;
}

.feedback.no {
  background: #fff5f5;
  border: 1px solid #fed7d7;
  color: #742a2a;
}
.feedback strong {
  font-size: 15px;
}

.actions {
  margin-top: 24px;
  display: flex;
  gap: 12px;
}

.btn {
  flex: 1;
  padding: 14px;
  border: none;
  border-radius: 12px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: linear-gradient(90deg, #4f46e5, #7c3aed);
  color: #fff;
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.4);
}

.btn-next {
  background: #eef2ff;
  color: #4f46e5;
}

.btn-next:hover {
  background: #e0e7ff;
}

.footer {
  text-align: center;
  margin-top: 20px;
  color: #a0aec0;
  font-size: 13px;
}

@media (max-width: 480px) {
  .header h1 {
    font-size: 22px;
  }

  .card {
    padding: 20px;
  }

  .question-text {
    font-size: 16px;
  }
}