.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: var(--color-background);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  display: flex;
  align-items: center;
}

.nav-container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-primary);
}

.nav-links {
  display: flex;
  gap: var(--spacing-sm);
}

.nav-link {
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  background: transparent;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.nav-link:hover {
  background: var(--color-surface-2);
  color: var(--color-text-primary);
}

.nav-link.active {
  background: var(--color-surface-1);
  color: var(--color-text-primary);
  border-color: var(--color-border);
}

.nav-tools {
  display: flex;
  gap: var(--spacing-sm);
}

.theme-toggle,
.sidebar-btn {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: transparent;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  transition: all 0.15s ease;
}

.theme-toggle:hover,
.sidebar-btn:hover {
  background: var(--color-surface-2);
}



.main-content {
  margin-top: 60px;
  min-height: calc(100vh - 60px);
  padding: var(--spacing-xl);
}

.mode-content {
  display: none;
  max-width: 1200px;
  margin: 0 auto;
}

.mode-content.active {
  display: block;
}


.mode-content h2 {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.mode-content > p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
}



.knowledge-graph {
  position: relative;
  background: linear-gradient(135deg, #F8FAFC 0%, #F1F5F9 50%, #E2E8F0 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  min-height: 550px;
  height: 60vh;
  overflow: hidden;
}

.knowledge-graph canvas {
  cursor: grab;
  max-width: none;
}

.knowledge-graph canvas:active {
  cursor: grabbing;
}

.graph-controls {
  position: absolute;
  top: var(--spacing-md);
  left: var(--spacing-md);
  right: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 10;
  pointer-events: none;
}

.graph-controls > * {
  pointer-events: auto;
}

.graph-controls-right {
  display: flex;
  gap: var(--spacing-xs);
}

.graph-btn {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.5);
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  transition: all 0.15s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.graph-btn:hover {
  background: rgba(255, 255, 255, 0.9);
  color: var(--color-text-primary);
}

.layout-switcher {
  display: flex;
  gap: 2px;
  background: rgba(255, 255, 255, 0.5);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: var(--radius-sm);
  padding: 2px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.layout-btn {
  width: 28px;
  height: 28px;
  border-radius: 4px;
  border: none;
  background: transparent;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: var(--color-text-tertiary);
  transition: all 0.15s ease;
}

.layout-btn:hover {
  background: rgba(255, 255, 255, 0.6);
  color: var(--color-text-secondary);
}

.layout-btn.active {
  background: var(--color-background);
  color: var(--color-primary);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.graph-hint {
  position: absolute;
  bottom: var(--spacing-md);
  left: 50%;
  transform: translateX(-50%);
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(255, 255, 255, 0.6);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  white-space: nowrap;
  pointer-events: none;
  z-index: 10;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}



.process-header {
  margin-bottom: var(--spacing-xl);
}

.process-header p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.process-progress {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-top: var(--spacing-md);
}

.progress-bar {
  flex: 1;
  height: 6px;
  background: var(--color-border);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, #6366F1, #8B5CF6);
  border-radius: 3px;
  transition: width 0.4s ease;
}

.progress-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.process-guide {
  max-width: 1200px;
}

.timeline {
  position: relative;
  padding-left: var(--spacing-xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 12px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-lg);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -25px;
  top: 24px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid var(--color-background);
  z-index: 1;
  transition: background 0.3s;
}

.timeline-item.completed::before {
  background: #10B981;
}

.step-card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all 0.2s ease;
}

.step-card:hover {
  border-color: var(--color-border-strong);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.timeline-item.completed .step-card {
  border-color: #10B981;
}

.step-header {
  padding: var(--spacing-lg);
  cursor: pointer;
  user-select: none;
  position: relative;
}

.step-header:hover {
  background: var(--color-surface-1);
}

.step-number {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-xs);
}

.step-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-xs);
}

.step-desc {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.step-meta {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.meta-tag {
  font-size: var(--font-size-xs);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
}

.meta-tag.time {
  background: rgba(99, 102, 241, 0.08);
  color: #6366F1;
}

.meta-tag.difficulty {
  background: rgba(245, 158, 11, 0.08);
  color: #D97706;
}

.expand-icon {
  position: absolute;
  right: var(--spacing-lg);
  top: var(--spacing-lg);
  font-size: 14px;
  color: var(--color-text-tertiary);
  transition: transform 0.3s ease;
}

.step-card.open .expand-icon {
  transform: rotate(180deg);
}

.step-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 var(--spacing-lg);
}

.step-card.open .step-body {
  max-height: 800px;
  padding: 0 var(--spacing-lg) var(--spacing-lg);
}

.step-details {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

.detail-card {
  background: var(--color-surface-1);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
}

.detail-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.detail-card ul {
  list-style: none;
  padding: 0;
}

.step-check {
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border-subtle);
}

.check-label {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  cursor: pointer;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.check-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: #10B981;
  cursor: pointer;
}
  color: var(--color-text-secondary);
  padding: var(--spacing-xs) 0;
  border-bottom: 1px solid var(--color-border-subtle);
}

.detail-card li:last-child {
  border-bottom: none;
}

.detail-card p {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin: 0;
}



.encyclopedia {
  max-width: 1200px;
}



.quiz-container {
  padding: var(--spacing-md);
}


.quiz-modules {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.quiz-module-card {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background: var(--color-surface-1);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
}

.quiz-module-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--color-border-subtle);
  transition: background 0.2s;
}

.quiz-module-card:hover {
  border-color: var(--color-primary);
  box-shadow: 0 4px 12px rgba(94, 106, 210, 0.1);
  transform: translateY(-2px);
}

.quiz-module-card.complete::before {
  background: #10B981;
}

.quiz-module-card.partial::before {
  background: #F59E0B;
}

.module-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  flex-shrink: 0;
}

.module-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #EEF2FF, #F8FAFC);
  border-radius: 14px;
  border: 1px solid #E2E8F0;
  color: #5E6AD2;
}

.module-icon svg {
  width: 26px;
  height: 26px;
}

.complete-badge {
  width: 24px;
  height: 24px;
  background: #10B981;
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 700;
}

.module-info {
  flex: 1;
  min-width: 0;
}

.module-info h3 {
  margin: 0 0 4px;
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  font-weight: 600;
}

.module-info p {
  margin: 0 0 8px;
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  line-height: 1.4;
}

.progress-bar {
  height: 6px;
  background: var(--color-border-subtle);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 6px;
}

.progress-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.3s ease;
}

.module-count {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}

.module-start-btn {
  padding: 8px 16px;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: background 0.2s;
  white-space: nowrap;
}

.module-start-btn:hover {
  background: #4A55B8;
}


.module-buttons {
  display: flex;
  gap: 8px;
  flex-direction: column;
  flex-shrink: 0;
  min-width: 100px;
}

.module-btn {
  padding: 8px 14px;
  font-size: 13px;
  border-radius: 8px;
  border: 1px solid var(--color-border-subtle);
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
  font-weight: 500;
}

.module-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(94, 106, 210, 0.05);
}

.module-btn.random {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.module-btn.random:hover {
  background: #4A55B8;
  border-color: #4A55B8;
  color: #fff;
}


.category-section {
  margin-bottom: var(--spacing-xl);
}

.category-name {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0 0 var(--spacing-md) 0;
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}


.category-modules {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
}


.quiz-active {
  grid-column: 1 / -1;
  width: 100%;
  max-width: none;
}

.quiz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-md);
}

.quiz-back-btn {
  padding: 6px 12px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  transition: color 0.2s;
}

.quiz-back-btn:hover {
  color: var(--color-text-primary);
}

.quiz-progress-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  font-weight: 500;
}


.quiz-progress-bar {
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  margin-bottom: var(--spacing-2xl);
  overflow: hidden;
}

.quiz-progress-fill {
  height: 100%;
  background: var(--color-primary);
  border-radius: 2px;
  transition: width 0.3s ease;
}


.quiz-question {
  margin-bottom: var(--spacing-xl);
}

.quiz-question-text {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: 1.5;
  margin: 0;
}


.quiz-options {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
  gap: var(--spacing-sm);
}

.quiz-option {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.15s ease;
  text-align: left;
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
}

.quiz-option:hover {
  border-color: var(--color-primary);
  background: rgba(94, 106, 210, 0.03);
}

.option-letter {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-surface-1);
  color: var(--color-text-tertiary);
  font-size: var(--font-size-sm);
  font-weight: 500;
  flex-shrink: 0;
}

.option-text {
  flex: 1;
}

.option-icon {
  font-size: var(--font-size-base);
  font-weight: 600;
}

.quiz-option.correct {
  border-color: #10B981;
  background: rgba(16, 185, 129, 0.05);
}

.quiz-option.correct .option-letter {
  background: #10B981;
  color: #fff;
}

.quiz-option.correct .option-icon {
  color: #10B981;
}

.quiz-option.wrong {
  border-color: #EF4444;
  background: rgba(239, 68, 68, 0.05);
}

.quiz-option.wrong .option-letter {
  background: #EF4444;
  color: #fff;
}

.quiz-option.wrong .option-icon {
  color: #EF4444;
}

.quiz-option.show-correct {
  border-color: #10B981;
  background: rgba(16, 185, 129, 0.03);
}


.quiz-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
}

.quiz-nav-btn {
  padding: 10px 20px;
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
}

.quiz-nav-btn:hover:not(:disabled) {
  border-color: var(--color-text-tertiary);
  color: var(--color-text-primary);
}

.quiz-nav-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.quiz-nav-btn.primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.quiz-nav-btn.primary:hover {
  background: #4A55B8;
  border-color: #4A55B8;
}

.quiz-summary {
  padding: var(--spacing-lg);
  background: var(--color-surface-1);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-subtle);
}

.quiz-summary h3 {
  margin: 0 0 var(--spacing-md);
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
}

.summary-stats {
  display: flex;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--color-border-subtle);
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-num {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-primary);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}

.summary-details {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.detail-row {
  display: flex;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--color-border-subtle);
  font-size: var(--font-size-sm);
}

.detail-row:last-child {
  border-bottom: none;
}


.summary-top {
  display: flex;
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
}

.summary-stat {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.summary-stat .stat-num {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-primary);
}

.summary-stat .stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}

.summary-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.summary-tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  background: var(--color-surface-2);
  color: var(--color-text-secondary);
}

.summary-tag.tag-full {
  background: rgba(16, 185, 129, 0.1);
  color: #10B981;
}

.summary-tag.tag-partial {
  background: rgba(245, 158, 11, 0.1);
  color: #F59E0B;
}

.summary-tag.tag-zero {
  background: rgba(239, 68, 68, 0.1);
  color: #EF4444;
}


.quiz-result-view {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing-xl);
}

.result-top {
  text-align: center;
  padding: var(--spacing-xl) 0;
  border-bottom: 1px solid var(--color-border-subtle);
  margin-bottom: var(--spacing-xl);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.result-score {
  font-size: 48px;
  font-weight: 700;
  color: var(--color-primary);
}

.result-pct {
  font-size: 20px;
  color: var(--color-text-secondary);
}


.result-wrong-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.result-wrong-list h3 {
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.wrong-item {
  padding: var(--spacing-md);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  background: var(--color-surface-1);
}

.wrong-question {
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--color-text-primary);
}

.wrong-answers {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 8px;
  font-size: var(--font-size-sm);
}

.wrong-user {
  color: #EF4444;
}

.wrong-correct {
  color: #10B981;
}

.wrong-explain {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  padding: 8px 12px;
  background: var(--color-background);
  border-radius: var(--radius-sm);
  line-height: 1.6;
}


.quiz-result-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-border-subtle);
}

.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.quiz-header h3 {
  margin: 0;
  font-size: var(--font-size-lg);
}

.quiz-count {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}



.node-actions {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-sm);
}

.quiz-btn {
  display: inline-block;
  padding: 6px 14px;
  background: var(--accent-amber);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: background 0.2s;
}

.quiz-btn:hover {
  background: #D97706;
}

.search-box {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.search-input {
  flex: 1;
  height: 44px;
  padding: 0 var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  background: var(--color-background);
  color: var(--color-text-primary);
  transition: all 0.15s ease;
}

.search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(94, 106, 210, 0.15);
}

.search-btn {
  height: 44px;
  padding: 0 var(--spacing-lg);
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.search-btn:hover {
  background: #4a52b0;
}

.search-btn:active {
  transform: scale(0.97);
}

.category-filters {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: all 0.15s ease;
}

.filter-btn:hover {
  background: var(--color-surface-2);
  color: var(--color-text-primary);
}

.filter-btn.active {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.article-card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all 0.2s ease;
}

.article-card:hover {
  border-color: var(--color-border-strong);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  transform: translateY(-2px);
}

.article-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.article-card > p {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.article-tags {
  display: flex;
  gap: var(--spacing-xs);
  flex-wrap: wrap;
}

.tag {
  padding: 2px var(--spacing-sm);
  background: var(--color-surface-1);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
}

.empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--spacing-3xl) var(--spacing-lg);
  color: var(--color-text-tertiary);
  font-size: var(--font-size-base);
}

.article-detail-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.article-detail-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.article-detail-panel {
  background: var(--color-background);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 720px;
  max-height: 85vh;
  overflow-y: auto;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
  transform: translateY(20px);
  transition: transform 0.25s ease;
}

.article-detail-overlay.open .article-detail-panel {
  transform: translateY(0);
}

.detail-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.detail-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.detail-overlay .detail-panel {
  background: var(--color-background);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 720px;
  max-height: 85vh;
  overflow-y: auto;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
  transform: translateY(20px);
  transition: transform 0.25s ease;
}

.detail-overlay.open .detail-panel {
  transform: translateY(0);
}

.detail-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: var(--spacing-sm);
  padding: 8px 16px;
  background: var(--color-primary);
  color: #fff;
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.detail-btn:hover {
  background: #4A55B8;
  border-color: #4A55B8;
}

.detail-content {
  padding: var(--spacing-xl);
  line-height: 1.8;
  color: var(--color-text-primary);
}

.detail-content h2 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-md);
}

.detail-content h3 {
  font-size: var(--font-size-lg);
  margin: var(--spacing-lg) 0 var(--spacing-sm);
}

.detail-content table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-md) 0;
}

.detail-content th, .detail-content td {
  padding: 8px 12px;
  border: 1px solid var(--color-border-subtle);
  text-align: left;
}

.detail-content th {
  background: var(--color-surface-1);
  font-weight: 600;
}

.detail-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: var(--spacing-xl);
  border-bottom: 1px solid var(--color-border-subtle);
}

.detail-header h2 {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-xs);
}

.detail-category {
  font-size: var(--font-size-xs);
  padding: 2px 10px;
  border-radius: var(--radius-full);
  background: rgba(99, 102, 241, 0.08);
  color: #6366F1;
}

.detail-close {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: none;
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
  font-size: 18px;
  cursor: pointer;
  flex-shrink: 0;
  transition: all 0.15s;
}

.detail-close:hover {
  background: var(--color-surface-2);
  color: var(--color-text-primary);
}

.detail-tags {
  padding: var(--spacing-md) var(--spacing-xl);
  display: flex;
  gap: var(--spacing-xs);
  flex-wrap: wrap;
}



.detail-body {
  padding: 0 var(--spacing-xl) var(--spacing-xl);
  line-height: 1.8;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}


.block-heading {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: var(--spacing-xl) 0 var(--spacing-md);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-border);
}

.heading-marker {
  width: 4px;
  height: 22px;
  border-radius: 2px;
  background: var(--color-primary);
  flex-shrink: 0;
}

.block-heading h2 {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text-primary);
  margin: 0;
}


.block-subheading {
  margin: var(--spacing-lg) 0 var(--spacing-sm);
}

.block-subheading h3 {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0;
  padding-left: var(--spacing-md);
  border-left: 3px solid var(--color-border-strong);
}

.block-point {
  margin: var(--spacing-md) 0 var(--spacing-xs);
}

.block-point h4 {
  font-size: calc(var(--font-size-base) - 1px);
  font-weight: 600;
  color: var(--color-primary);
  margin: 0;
  padding-left: calc(var(--spacing-md) + var(--spacing-sm));
  position: relative;
}

.block-point h4::before {
  content: "";
  position: absolute;
  left: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-primary);
}


.block-paragraph {
  margin-bottom: var(--spacing-sm);
}

.block-paragraph p {
  margin: 0;
}

.block-paragraph strong {
  color: var(--color-text-primary);
  font-weight: 600;
}


.block-list {
  background: var(--color-surface-1);
  border-radius: var(--radius-md);
  padding: var(--spacing-md) var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

.block-list ul, .block-list ol {
  margin: 0;
  padding-left: var(--spacing-lg);
}

.block-list li {
  margin-bottom: 6px;
  line-height: 1.7;
}

.block-list li:last-child {
  margin-bottom: 0;
}

.block-list li::marker {
  color: var(--color-primary);
}

.block-list strong {
  color: var(--color-text-primary);
  font-weight: 600;
}


.block-table {
  margin-bottom: var(--spacing-md);
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
}

.block-table table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

.block-table th {
  background: var(--color-surface-1);
  font-weight: 600;
  color: var(--color-text-primary);
  text-align: left;
  padding: var(--spacing-sm) var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
}

.block-table td {
  padding: var(--spacing-sm) var(--spacing-md);
  border-bottom: 1px solid var(--color-border-subtle);
  color: var(--color-text-secondary);
}

.block-table tr:last-child td {
  border-bottom: none;
}

.block-table tr:hover td {
  background: var(--color-surface-1);
}



.sidebar {
  position: fixed;
  right: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  z-index: 100;
}



.memory-panel {
  position: fixed;
  top: 60px;
  right: -360px;
  width: 360px;
  height: calc(100vh - 60px);
  background: var(--color-background);
  border-left: 1px solid var(--color-border);
  z-index: 999;
  transition: right 0.3s ease;
  overflow-y: auto;
}

.memory-panel.open {
  right: 0;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--spacing-lg);
  border-bottom: 1px solid var(--color-border);
}

.panel-header h3 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0;
}

.close-btn {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  cursor: pointer;
  font-size: 20px;
  color: var(--color-text-secondary);
  transition: all 0.15s ease;
}

.close-btn:hover {
  background: var(--color-surface-2);
  color: var(--color-text-primary);
}

.memory-section {
  padding: var(--spacing-md) var(--spacing-lg);
  border-bottom: 1px solid var(--color-border-subtle);
}

.section-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.history-item {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--color-border-subtle);
}

.history-item:last-child {
  border-bottom: none;
}

.progress-item {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.progress-item .progress-num {
  float: right;
  font-weight: 600;
  color: var(--color-text-primary);
}

.progress-track {
  background: #eee;
  height: 10px;
  border-radius: 5px;
  margin-top: 5px;
}

.progress-fill {
  height: 100%;
  border-radius: 5px;
  transition: width 0.5s ease;
}

.progress-fill.graph-fill {
  background: var(--accent-emerald);
}

.progress-fill.process-fill {
  background: var(--color-primary);
}

.history-item.empty {
  color: var(--color-text-tertiary);
  font-style: italic;
}



.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 500;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
  border: none;
  outline: none;
  text-decoration: none;
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.97);
}

.btn:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(94, 106, 210, 0.3);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.btn--primary {
  background: var(--color-primary);
  color: white;
}

.btn--primary:hover {
  background: #4a52b0;
}

.btn--secondary {
  background: transparent;
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.btn--secondary:hover {
  background: var(--color-surface-2);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text-secondary);
}

.btn--ghost:hover {
  background: var(--color-surface-2);
  color: var(--color-text-primary);
}



.card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  transition: all 0.2s ease;
}

.card:hover {
  border-color: var(--color-border-strong);
}

.card--glass {
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.18);
}

[data-theme="dark"] .card--glass {
  background: rgba(15, 16, 17, 0.72);
  border: 1px solid rgba(255, 255, 255, 0.1);
}



.input {
  height: 44px;
  padding: 0 var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  background: var(--color-background);
  color: var(--color-text-primary);
  transition: all 0.15s ease;
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(94, 106, 210, 0.15);
}

.input::placeholder {
  color: var(--color-text-tertiary);
}



.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px var(--spacing-sm);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.badge--primary {
  background: rgba(94, 106, 210, 0.1);
  color: var(--color-primary);
}

.badge--success {
  background: rgba(34, 197, 94, 0.1);
  color: #22c55e;
}

.badge--warning {
  background: rgba(245, 158, 11, 0.1);
  color: #f59e0b;
}

.badge--error {
  background: rgba(239, 68, 68, 0.1);
  color: #ef4444;
}

.badge--neutral {
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
}



.node-info-panel {
  position: absolute;
  bottom: var(--spacing-lg);
  left: var(--spacing-lg);
  width: 300px;
  max-height: 400px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.5);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15), inset 0 1px 1px rgba(255, 255, 255, 0.5);
  display: none;
  z-index: 10;
  overflow: auto;
}

[data-theme="dark"] .node-info-panel {
  background: rgba(30, 32, 36, 0.95);
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4), inset 0 1px 1px rgba(255, 255, 255, 0.08);
}

.node-info-header {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--color-border-subtle);
}

.node-info-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-xs);
}

.node-info-header h3 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0;
}

.learn-toggle-btn {
  padding: 2px 10px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  font-size: var(--font-size-xs);
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.learn-toggle-btn:hover {
  background: var(--color-surface-2);
}

.learn-toggle-btn.learned {
  background: rgba(16, 185, 129, 0.1);
  color: #10B981;
  border-color: #10B981;
}

.node-category {
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 500;
}

.node-info-content {
  padding: var(--spacing-md);
}

.node-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: var(--spacing-md);
}

.related-section {
  margin-bottom: var(--spacing-sm);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.related-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  font-weight: 500;
}

.related-tag {
  display: inline-block;
  padding: 2px 8px;
  background: var(--color-surface-1);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

.related-tag:hover {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

.node-actions {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--color-border-subtle);
}

.btn-reset-view {
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  font-size: var(--font-size-xs);
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-reset-view:hover {
  background: var(--color-surface-2);
  color: var(--color-text-primary);
}


/* ===== 知识图谱 · 移动端聚焦式分支导航（方案 C） ===== */
.graph-focus-view {
  display: none;
}

.focus-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}

.focus-up {
  flex: 0 0 auto;
  border: 1px solid var(--color-border);
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  font-size: var(--font-size-sm);
  cursor: pointer;
}

.focus-path {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.focus-current {
  display: flex;
}

.focus-node-card {
  flex: 1;
  background: var(--color-surface-1);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--cat, var(--color-primary));
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.focus-cat {
  display: inline-block;
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: var(--spacing-xs);
}

.focus-node-card h3 {
  margin: 0 0 var(--spacing-sm);
  font-size: var(--font-size-xl, 20px);
  color: var(--color-text-primary);
}

.focus-node-card > p {
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin: 0 0 var(--spacing-md);
  font-size: var(--font-size-sm);
}

.focus-node-actions {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.focus-node-actions .learn-toggle-btn {
  border: 1px solid var(--color-primary);
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-sm);
  padding: 8px 16px;
  font-size: var(--font-size-sm);
  cursor: pointer;
}

.focus-node-actions .learn-toggle-btn.learned {
  background: var(--accent-emerald, #10B981);
  border-color: var(--accent-emerald, #10B981);
}

.focus-node-actions .detail-btn {
  border: 1px solid var(--color-border);
  background: var(--color-surface-2);
  color: var(--color-text-primary);
  border-radius: var(--radius-sm);
  padding: 8px 16px;
  font-size: var(--font-size-sm);
  cursor: pointer;
}

.focus-children-wrap {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.focus-children-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}

.focus-children {
  display: flex;
  gap: var(--spacing-md);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scroll-snap-type: x mandatory;
  padding-bottom: var(--spacing-xs);
}

.focus-children::-webkit-scrollbar {
  height: 6px;
}

.focus-children::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

.focus-child-card {
  position: relative;
  flex: 0 0 72%;
  scroll-snap-align: start;
  background: var(--color-surface-1);
  border: 1px solid var(--color-border);
  border-top: 3px solid var(--cat, var(--color-primary));
  border-radius: var(--radius-md, 12px);
  padding: var(--spacing-md);
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.focus-child-card:active {
  transform: scale(0.98);
}

.focus-child-name {
  font-weight: 600;
  font-size: var(--font-size-md, 16px);
  color: var(--color-text-primary);
  margin-bottom: 4px;
}

.focus-child-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.focus-learned {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--accent-emerald, #10B981);
  color: #fff;
  font-size: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.focus-leaf {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  text-align: center;
  padding: var(--spacing-md);
  background: var(--color-surface-2);
  border-radius: var(--radius-md, 12px);
}

.focus-actions {
  display: flex;
  justify-content: center;
}

.btn-open-graph {
  border: 1px solid var(--color-border);
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  padding: 10px 20px;
  font-size: var(--font-size-sm);
  cursor: pointer;
}

#focusBackBtn {
  display: none;
}

@media (max-width: 768px) {
  .navbar {
    height: auto;
    padding: 8px 0;
  }

  .nav-container {
    flex-wrap: wrap;
    row-gap: 8px;
  }

  .nav-links {
    order: 3;
    flex: 1 1 100%;
    display: flex;
    gap: var(--spacing-xs);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .nav-links::-webkit-scrollbar {
    display: none;
  }

  .nav-link {
    flex: 0 0 auto;
    white-space: nowrap;
  }

  .sidebar {
    display: none;
  }

  .main-content {
    padding: var(--spacing-md);
    margin-top: 108px;
  }

  .knowledge-graph {
    display: none;
    overflow-x: auto;
    overflow-y: hidden;
    height: 65vh;
    min-height: 480px;
    -webkit-overflow-scrolling: touch;
  }

  #graphMode.focus-mode .knowledge-graph {
    display: block;
  }

  .graph-focus-view {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
  }

  #graphMode.focus-mode .graph-focus-view {
    display: none;
  }

  .knowledge-graph::-webkit-scrollbar {
    height: 6px;
  }

  .knowledge-graph::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 3px;
  }

  #focusBackBtn {
    display: inline-flex;
  }
  
  .step-details {
    grid-template-columns: 1fr;
  }
  
  .articles-grid {
    grid-template-columns: 1fr;
  }
  
  .memory-panel {
    width: 100%;
    right: -100%;
  }
  
  .node-info-panel {
    width: calc(100% - 32px);
    left: var(--spacing-md);
    bottom: var(--spacing-md);
  }
  
  .quiz-question-text {
    font-size: var(--font-size-lg);
  }
}

@media (min-width: 992px) {
  .quiz-active {
    padding: 0 var(--spacing-xl);
  }
  
  .quiz-question-text {
    font-size: var(--font-size-2xl);
  }
  
  .quiz-option {
    padding: var(--spacing-md) var(--spacing-xl);
  }
}

/* ========================================
   闯关模式样式
   ======================================== */

.challenge-stages {
  display: flex;
  flex-direction: column;
  gap: 24px;
  max-width: 1200px;
  margin: 0 auto;
  position: relative;
}

.challenge-stages::before {
  content: '';
  position: absolute;
  left: 40px;
  top: 60px;
  bottom: 60px;
  width: 3px;
  background: linear-gradient(180deg, #5E6AD2, #7C8CE8, #A5B4FC);
  border-radius: 2px;
  z-index: 0;
}

.challenge-stage {
  display: flex;
  gap: 20px;
  position: relative;
  z-index: 1;
}

.stage-indicator {
  flex-shrink: 0;
  width: 80px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stage-num {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, #5E6AD2, #7C8CE8);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  font-weight: 700;
  box-shadow: 0 4px 12px rgba(94, 106, 210, 0.3);
  transition: all 0.3s ease;
}

.stage-label {
  font-size: 13px;
  color: #64748B;
  margin-top: 8px;
  font-weight: 500;
  text-align: center;
}

.challenge-stage.locked .stage-num {
  background: #CBD5E1;
  box-shadow: none;
}

.challenge-stage.locked .stage-label {
  color: #94A3B8;
}

.challenge-stage.completed .stage-num {
  background: linear-gradient(135deg, #10B981, #34D399);
}

.challenge-stage.active .stage-num {
  box-shadow: 0 0 0 4px rgba(94, 106, 210, 0.2);
}

.stage-content {
  flex: 1;
  background: var(--color-surface-1);
  border-radius: 20px;
  padding: 24px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
  border: 2px solid transparent;
  transition: all 0.2s ease;
}

.challenge-stage:not(.locked):hover .stage-content {
  border-color: rgba(94, 106, 210, 0.2);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(94, 106, 210, 0.12);
}

.stage-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.stage-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text-primary);
}

.stage-badge {
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 20px;
  font-weight: 500;
}

.stage-badge.complete {
  background: rgba(16, 185, 129, 0.1);
  color: #10B981;
}

.stage-badge.available {
  background: rgba(94, 106, 210, 0.1);
  color: #5E6AD2;
}

.stage-badge.locked {
  background: rgba(148, 163, 184, 0.1);
  color: #94A3B8;
}

.stage-desc {
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-bottom: 16px;
  line-height: 1.5;
}

.stage-modules {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.module-tag {
  font-size: 12px;
  padding: 4px 10px;
  background: var(--color-background);
  border-radius: 8px;
  color: var(--color-text-secondary);
}

.stage-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  border-top: 1px solid var(--color-border-subtle);
}

.stage-requirement {
  font-size: 13px;
  color: var(--color-text-tertiary);
}

.btn-start {
  padding: 10px 24px;
  background: linear-gradient(135deg, #5E6AD2, #7C8CE8);
  color: #fff;
  border: none;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-start:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(94, 106, 210, 0.3);
}

.btn-locked {
  font-size: 13px;
  color: var(--color-text-tertiary);
  font-style: italic;
}

.challenge-flow {
  max-width: 1200px;
  margin: 0 auto;
}

/* 闯关步骤指示器 · Fathom 数据叙事风格（方案 A） */
.step-indicator {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
  margin-bottom: 32px;
  --si-primary: #5E6AD2;
  --si-primary-2: #7C8CE8;
  --si-muted: #94A3B8;
  --si-border: #E2E8F0;
  --si-grad: linear-gradient(135deg, #5E6AD2, #7C8CE8);
}

.step-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  min-width: 56px;
}

.step-dot {
  position: relative;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  border: 2px solid var(--si-border);
  background: #fff;
  color: var(--si-muted);
  transition: all 0.3s ease;
}

.step-dot.completed {
  background: var(--si-grad);
  border-color: transparent;
  color: #fff;
}

.step-dot.completed::after {
  content: "✓";
  position: absolute;
  top: -4px;
  right: -4px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #fff;
  color: var(--si-primary);
  font-size: 11px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 6px rgba(15, 23, 42, 0.15);
}

.step-dot.active {
  background: var(--si-grad);
  border-color: transparent;
  color: #fff;
  transform: scale(1.12);
  box-shadow: 0 8px 22px rgba(94, 106, 210, 0.4);
}

.step-label {
  font-size: 12px;
  color: #64748B;
  font-weight: 500;
  transition: color 0.3s ease;
}

.step-col.active-col .step-label {
  color: #0F172A;
  font-weight: 600;
}

.step-line {
  flex: 0 0 40px;
  height: 3px;
  border-radius: 2px;
  background: var(--si-border);
  margin-top: 22px;
  transition: background 0.3s ease;
}

.step-line.done {
  background: var(--si-grad);
}

.step-content {
  background: var(--color-surface-1);
  border-radius: 20px;
  padding: 32px;
  min-height: 300px;
}

.read-step h3,
.graph-step h3,
.quiz-step h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--color-text-primary);
}

.read-step p,
.graph-step p,
.quiz-step p {
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-bottom: 24px;
}

.read-modules {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.read-module-card {
  background: var(--color-background);
  border-radius: 16px;
  padding: 16px;
  text-align: center;
  border: 1px solid var(--color-border-subtle);
  transition: all 0.2s ease;
}

.read-module-card:hover {
  border-color: rgba(94, 106, 210, 0.3);
  transform: translateY(-2px);
}

.read-module-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto 12px;
  color: #5E6AD2;
}

.read-module-icon svg {
  width: 100%;
  height: 100%;
}

.read-module-name {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-primary);
  margin-bottom: 12px;
}

.btn-read {
  padding: 6px 16px;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-read:hover {
  background: #4A55B8;
}

.graph-preview {
  background: var(--color-background);
  border-radius: 16px;
  padding: 40px;
  text-align: center;
  margin-bottom: 24px;
}

.graph-preview p {
  margin-bottom: 16px;
}

.btn-open-graph {
  padding: 10px 24px;
  background: transparent;
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-open-graph:hover {
  background: var(--color-primary);
  color: #fff;
}

.quiz-actions {
  text-align: center;
  margin-bottom: 24px;
}

.btn-start-quiz {
  padding: 14px 40px;
  background: linear-gradient(135deg, #5E6AD2, #7C8CE8);
  color: #fff;
  border: none;
  border-radius: 14px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-start-quiz:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 20px rgba(94, 106, 210, 0.3);
}

.step-actions {
  display: flex;
  justify-content: space-between;
  padding-top: 24px;
  border-top: 1px solid var(--color-border-subtle);
}

.btn-prev,
.btn-next {
  padding: 10px 24px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-prev {
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  color: var(--color-text-secondary);
}

.btn-prev:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-next {
  background: var(--color-primary);
  border: none;
  color: #fff;
}

.btn-next:hover {
  background: #4A55B8;
}

.pass-result,
.fail-result {
  text-align: center;
  padding: 40px;
}

.pass-icon,
.fail-icon {
  font-size: 64px;
  margin-bottom: 20px;
}

.pass-result h3,
.fail-result h3 {
  font-size: 24px;
  margin-bottom: 12px;
}

.pass-result p,
.fail-result p {
  font-size: 16px;
  color: var(--color-text-secondary);
  margin-bottom: 24px;
}

.score-display {
  font-size: 48px;
  font-weight: 700;
  color: #5E6AD2;
  margin-bottom: 12px;
}

.fail-message {
  font-size: 14px;
  color: var(--color-text-tertiary);
  margin-bottom: 24px;
}

.pass-actions,
.fail-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
}

.btn-back,
.btn-retry {
  padding: 12px 28px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-back {
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  color: var(--color-text-secondary);
}

.btn-back:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-retry {
  background: linear-gradient(135deg, #5E6AD2, #7C8CE8);
  border: none;
  color: #fff;
}

.btn-retry:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(94, 106, 210, 0.3);
}

/* 闯关模式 - 阅读步骤文章链接 */
.read-article-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.read-article-link {
  font-size: 13px;
  color: #5E6AD2;
  cursor: pointer;
  padding: 4px 12px;
  border-radius: 8px;
  background: rgba(94, 106, 210, 0.08);
  border: 1px solid var(--color-border-subtle, rgba(94, 106, 210, 0.2));
  transition: all 0.2s ease;
}

.read-article-link:hover {
  background: rgba(94, 106, 210, 0.16);
}

.read-article-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  padding: 16px 12px;
  border-radius: 12px;
  background: var(--color-surface-2, rgba(148, 163, 184, 0.06));
  border: 1px dashed var(--color-border-subtle, #E2E8F0);
  text-align: center;
}

.read-article-empty .empty-icon {
  width: 28px;
  height: 28px;
  color: var(--color-text-tertiary, #94A3B8);
  opacity: 0.7;
}

.read-article-empty p {
  font-size: 13px;
  color: var(--color-text-tertiary, #94A3B8);
  margin: 0;
}

.read-article-empty .btn-link {
  font-size: 12px;
  font-weight: 600;
  color: #5E6AD2;
  background: rgba(94, 106, 210, 0.1);
  border: none;
  border-radius: 8px;
  padding: 6px 14px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.read-article-empty .btn-link:hover {
  background: rgba(94, 106, 210, 0.18);
}

/* 闯关阅读步骤 - 方案3：双层概览 + 文章流 */
.read-overview {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 14px;
  margin-bottom: 24px;
}
.read-mod-card {
  background: var(--color-background);
  border: 1px solid var(--color-border, #E5E7EB);
  border-radius: 16px;
  padding: 16px 12px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  transition: all 0.2s ease;
}
.read-mod-card:hover {
  border-color: rgba(94, 106, 210, 0.4);
  transform: translateY(-2px);
}
.read-mod-card.active {
  border-color: #5E6AD2;
  box-shadow: 0 4px 16px rgba(94, 106, 210, 0.18);
}
.read-ring {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: conic-gradient(#5E6AD2 calc(var(--p, 0) * 1%), rgba(94, 106, 210, 0.15) 0);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
.read-ring::before {
  content: '';
  position: absolute;
  inset: 5px;
  border-radius: 50%;
  background: var(--color-surface-1, #FFFFFF);
}
.read-ring span {
  position: relative;
  font-size: 12px;
  font-weight: 600;
  color: var(--color-text-primary, #1E293B);
}
.read-mod-icon {
  width: 30px;
  height: 30px;
  color: #5E6AD2;
  line-height: 0;
}
.read-mod-name {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text-primary, #1E293B);
}
.read-list-wrap {
  margin-bottom: 24px;
}
.read-list-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text-primary, #1E293B);
  margin: 0 0 12px;
}
.read-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.read-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  background: var(--color-background);
  border: 1px solid var(--color-border, #E5E7EB);
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s ease;
}
.read-item:hover {
  border-color: rgba(94, 106, 210, 0.4);
  background: rgba(94, 106, 210, 0.06);
}
.read-idx {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: rgba(94, 106, 210, 0.12);
  color: #5E6AD2;
  font-size: 12px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.read-title {
  flex: 1;
  font-size: 14px;
  color: var(--color-text-primary, #1E293B);
}
.read-item.done .read-title {
  color: var(--color-text-tertiary, #94A3B8);
  text-decoration: line-through;
}
.read-check {
  color: #22C55E;
  font-weight: 700;
  flex-shrink: 0;
}

/* 文章阅读器（内联全屏，替代弹窗） */
.article-reader {
  display: none;
  max-width: 760px;
  margin: 0 auto;
  padding: 8px 0 40px;
  animation: reader-fade 0.25s ease;
}
@keyframes reader-fade {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

/* 阅读态：沉浸式，隐藏顶部模式切换导航 */
body.reader-mode .navbar {
  display: none;
}
body.reader-mode .main-content {
  margin-top: 0;
}
.reader-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: #5E6AD2;
  background: rgba(94, 106, 210, 0.1);
  border: none;
  border-radius: 8px;
  padding: 8px 14px;
  cursor: pointer;
  margin-bottom: 16px;
  transition: all 0.2s ease;
}
.reader-back:hover { background: rgba(94, 106, 210, 0.18); }
.reader-back svg { width: 16px; height: 16px; }
.reader-article {
  background: var(--color-surface, #FFFFFF);
  border-radius: 16px;
  padding: 28px 32px;
  box-shadow: 0 2px 16px rgba(15, 23, 42, 0.06);
}
.reader-head { display: flex; flex-direction: column; gap: 6px; align-items: flex-start; }
.reader-head h2 { font-size: 24px; font-weight: 700; line-height: 1.35; margin: 0; color: var(--color-text, #1E293B); }
.reader-summary {
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-text-secondary, #475569);
  margin: 16px 0 0;
  padding: 14px 16px;
  background: var(--color-surface-2, rgba(94, 106, 210, 0.06));
  border-left: 3px solid #5E6AD2;
  border-radius: 8px;
}
.reader-section-title { font-size: 16px; font-weight: 700; margin: 24px 0 12px; color: var(--color-text, #1E293B); }
.key-points { display: flex; flex-direction: column; gap: 10px; }
.kp-card {
  padding: 12px 16px;
  background: var(--color-surface-2, rgba(148, 163, 184, 0.07));
  border: 1px solid var(--color-border-subtle, #EEF2F7);
  border-radius: 10px;
}
.kp-card h4 { font-size: 14px; font-weight: 700; color: #5E6AD2; margin: 0 0 4px; }
.kp-card p { font-size: 14px; line-height: 1.65; color: var(--color-text-secondary, #475569); margin: 0; }
.reader-original {
  margin-top: 24px;
  border-top: 1px dashed var(--color-border-subtle, #E2E8F0);
  padding-top: 16px;
}
.reader-original summary { font-size: 13px; font-weight: 600; color: var(--color-text-tertiary, #94A3B8); cursor: pointer; }
.reader-original .detail-body { margin-top: 14px; }

/* 闯关模式 - 打印证书按钮 */
.btn-print {
  padding: 12px 28px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  background: linear-gradient(135deg, #5E6AD2, #7C8CE8);
  border: none;
  color: #fff;
  transition: all 0.2s ease;
}

.btn-print:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(94, 106, 210, 0.3);
}

/* 闯关模式 - 结业证书 */
.certificate {
  margin: 24px auto;
  max-width: 520px;
}

.cert-border {
  position: relative;
  border: 3px solid #5E6AD2;
  border-radius: 16px;
  padding: 40px 32px;
  background: linear-gradient(180deg, rgba(94, 106, 210, 0.06), rgba(124, 140, 232, 0.02));
  text-align: center;
}

.cert-seal {
  font-size: 56px;
}

.cert-title {
  font-size: 22px;
  font-weight: 700;
  color: #5E6AD2;
  margin-top: 8px;
}

.cert-sub {
  font-size: 12px;
  letter-spacing: 3px;
  color: var(--color-text-tertiary, #94a3b8);
  margin-top: 4px;
}

.cert-recipient {
  font-size: 28px;
  font-weight: 700;
  margin: 20px 0 8px;
}

.cert-text {
  font-size: 14px;
  color: var(--color-text-secondary, #64748b);
  margin-bottom: 20px;
}

.cert-stages {
  text-align: left;
  max-width: 360px;
  margin: 0 auto 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.cert-stage {
  display: flex;
  justify-content: space-between;
  font-size: 14px;
  padding: 8px 12px;
  border-radius: 8px;
  background: rgba(94, 106, 210, 0.06);
}

.cert-stage-status {
  color: var(--color-text-secondary, #64748b);
}

.cert-date {
  font-size: 13px;
  color: var(--color-text-tertiary, #94a3b8);
}

/* 闯关模式 - 移动端适配 */
@media (max-width: 768px) {
  .challenge-stage {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .stage-indicator {
    width: auto;
    flex-direction: row;
    align-items: center;
    gap: 12px;
  }

  .stage-num {
    width: 44px;
    height: 44px;
    font-size: 16px;
  }

  .challenge-stages::before {
    display: none;
  }

  .step-indicator {
    gap: 0;
  }

  .step-line {
    flex-basis: 24px;
  }

  .cert-border {
    padding: 28px 18px;
  }

  .cert-recipient {
    font-size: 22px;
  }
}

/* 打印时仅显示结业证书 */
@media print {
  body * {
    visibility: hidden;
  }

  .certificate,
  .certificate * {
    visibility: visible;
  }

  .certificate {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
  }
}

/* 简化 tab：图标 + 短标签 */
.nav-ico {
  margin-right: 4px;
  font-size: 14px;
  line-height: 1;
}

/* 设置面板 */
.settings-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.35);
  z-index: 998;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.settings-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.settings-panel {
  position: fixed;
  top: 0;
  right: -360px;
  width: 340px;
  max-width: 90vw;
  height: 100vh;
  background: var(--color-background);
  border-left: 1px solid var(--color-border);
  z-index: 999;
  transition: right 0.3s ease;
  display: flex;
  flex-direction: column;
}

.settings-panel.open {
  right: 0;
}

.settings-body {
  padding: var(--spacing-md) var(--spacing-lg);
  overflow-y: auto;
  flex: 1;
}

.settings-section {
  margin-bottom: var(--spacing-lg);
}

.settings-section .section-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.settings-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 12px 14px;
  background: var(--color-surface-1);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: all 0.15s ease;
  margin-bottom: var(--spacing-sm);
}

.settings-row:hover {
  border-color: var(--color-primary);
  background: rgba(94, 106, 210, 0.05);
}

.settings-row.danger {
  color: #EF4444;
}

.settings-row.danger:hover {
  border-color: #EF4444;
  background: rgba(239, 68, 68, 0.05);
}

.row-value {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  white-space: nowrap;
}

.settings-tip {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  line-height: 1.6;
  margin-top: var(--spacing-md);
}

/* 移动端：设置按钮常驻，隐藏文字标签只留图标 */
@media (max-width: 768px) {
  .nav-link {
    padding: var(--spacing-sm) var(--spacing-sm);
    font-size: var(--font-size-xs);
  }
}