/* 基础样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: #f8fafc;
  color: #1e293b;
  line-height: 1.6;
}

/* 侧边栏 */
.sidebar {
  width: 280px;
  height: 100vh;
  background: white;
  border-right: 1px solid #e2e8f0;
  position: fixed;
  left: 0;
  top: 0;
  display: flex;
  flex-direction: column;
  z-index: 100;
}

.sidebar-header {
  padding: 24px;
  border-bottom: 1px solid #e2e8f0;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-text {
  font-size: 20px;
  font-weight: 700;
  color: #1e293b;
}

.sidebar-nav {
  flex: 1;
  padding: 24px;
  overflow-y: auto;
}

.nav-section {
  margin-bottom: 32px;
}

.nav-section-title {
  font-size: 12px;
  font-weight: 600;
  color: #64748b;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 16px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: 8px;
  color: #64748b;
  text-decoration: none;
  transition: all 0.2s;
  margin-bottom: 4px;
}

.nav-item:hover {
  background: #f1f5f9;
  color: #1e293b;
}

.nav-item.active {
  background: #4f46e5;
  color: white;
}

.sidebar-footer {
  padding: 24px;
  border-top: 1px solid #e2e8f0;
}

.user-profile {
  display: flex;
  align-items: center;
  gap: 12px;
}

.avatar {
  width: 40px;
  height: 40px;
  background: #4f46e5;
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
}

.user-info {
  display: flex;
  flex-direction: column;
}

.user-name {
  font-weight: 600;
  color: #1e293b;
}

.user-streak {
  font-size: 12px;
  color: #64748b;
}

/* 主内容区 */
.main-content {
  margin-left: 280px;
  padding: 32px;
  min-height: 100vh;
}

/* 顶部栏 */
.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 32px;
}

.page-title {
  font-size: 28px;
  font-weight: 700;
  color: #1e293b;
}

.page-subtitle {
  color: #64748b;
  margin-top: 4px;
}

.top-bar-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.search-box {
  position: relative;
}

.search-box svg {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: #64748b;
}

.search-box input {
  padding: 10px 16px 10px 40px;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  width: 250px;
  font-size: 14px;
}

.search-box input:focus {
  outline: none;
  border-color: #4f46e5;
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
}

.btn-primary {
  background: #4f46e5;
  color: white;
}

.btn-primary:hover {
  background: #4338ca;
}

.btn-outline {
  background: white;
  border: 1px solid #e2e8f0;
  color: #64748b;
}

.btn-outline:hover {
  background: #f8fafc;
  border-color: #cbd5e1;
}

.btn-sm {
  padding: 6px 12px;
  font-size: 12px;
}

/* 统计卡片 */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 32px;
}

.stat-card {
  background: white;
  border-radius: 12px;
  padding: 24px;
  border: 1px solid #e2e8f0;
}

.stat-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.stat-icon--blue {
  background: #dbeafe;
  color: #3b82f6;
}

.stat-icon--green {
  background: #dcfce7;
  color: #22c55e;
}

.stat-icon--orange {
  background: #ffedd5;
  color: #f97316;
}

.stat-icon--purple {
  background: #f3e8ff;
  color: #a855f7;
}

.stat-value {
  font-size: 32px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 4px;
}

.stat-label {
  color: #64748b;
  font-size: 14px;
}

.stat-trend {
  font-size: 12px;
  margin-top: 8px;
}

.stat-trend.positive {
  color: #22c55e;
}

.stat-trend.negative {
  color: #ef4444;
}

/* 区块 */
.section {
  background: white;
  border-radius: 12px;
  padding: 24px;
  border: 1px solid #e2e8f0;
  margin-bottom: 32px;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.section-title {
  font-size: 20px;
  font-weight: 600;
  color: #1e293b;
}

.section-tabs {
  display: flex;
  gap: 8px;
}

.tab-btn {
  padding: 8px 16px;
  border-radius: 6px;
  border: none;
  background: #f1f5f9;
  color: #64748b;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
}

.tab-btn.active {
  background: #4f46e5;
  color: white;
}

.tab-btn:hover:not(.active) {
  background: #e2e8f0;
}

/* 考试卡片网格 */
.exam-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.exam-card {
  background: white;
  border-radius: 12px;
  padding: 24px;
  border: 1px solid #e2e8f0;
  transition: all 0.2s;
}

.exam-card:hover {
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.exam-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

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

.exam-card-badge.math {
  background: #dbeafe;
  color: #3b82f6;
}

.exam-card-badge.english {
  background: #dcfce7;
  color: #22c55e;
}

.exam-card-badge.science {
  background: #ffedd5;
  color: #f97316;
}

.exam-card-badge.history {
  background: #f3e8ff;
  color: #a855f7;
}

.exam-card-difficulty {
  display: flex;
  gap: 4px;
}

.difficulty-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #fbbf24;
}

.difficulty-dot-outline {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: 2px solid #e2e8f0;
}

.exam-card-title {
  font-size: 18px;
  font-weight: 600;
  color: #1e293b;
  margin-bottom: 8px;
}

.exam-card-desc {
  color: #64748b;
  font-size: 14px;
  margin-bottom: 16px;
  line-height: 1.5;
}

.exam-card-meta {
  display: flex;
  gap: 16px;
  margin-bottom: 16px;
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: #64748b;
}

.exam-card-progress {
  margin-bottom: 16px;
}

.progress-bar {
  height: 6px;
  background: #e2e8f0;
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 8px;
}

.progress-fill {
  height: 100%;
  background: #4f46e5;
  border-radius: 3px;
  transition: width 0.3s;
}

.progress-text {
  font-size: 12px;
  color: #64748b;
}

.exam-card-actions {
  display: flex;
  gap: 12px;
}

/* 活动列表 */
.activity-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.activity-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px;
  background: #f8fafc;
  border-radius: 8px;
}

.activity-icon {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.activity-icon--success {
  background: #dcfce7;
  color: #22c55e;
}

.activity-icon--warning {
  background: #ffedd5;
  color: #f97316;
}

.activity-content {
  flex: 1;
}

.activity-text {
  display: block;
  font-weight: 500;
  color: #1e293b;
  margin-bottom: 4px;
}

.activity-time {
  font-size: 12px;
  color: #64748b;
}

.activity-score {
  font-weight: 600;
  font-size: 14px;
}

.activity-score.positive {
  color: #22c55e;
}

.activity-score.negative {
  color: #ef4444;
}

/* 模态框 */
.modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  justify-content: center;
  align-items: center;
}

.modal {
  background: white;
  border-radius: 16px;
  width: 90%;
  max-width: 800px;
  max-height: 90vh;
  overflow: hidden;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px;
  border-bottom: 1px solid #e2e8f0;
}

.modal-title {
  font-size: 20px;
  font-weight: 600;
  color: #1e293b;
}

.modal-close {
  background: none;
  border: none;
  color: #64748b;
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
}

.modal-close:hover {
  background: #f1f5f9;
}

.modal-body {
  padding: 24px;
}

/* 考试计时器 */
.exam-timer {
  text-align: center;
  margin-bottom: 32px;
}

.timer-display {
  font-size: 48px;
  font-weight: 700;
  color: #1e293b;
  font-family: 'Courier New', monospace;
}

.timer-label {
  color: #64748b;
  font-size: 14px;
  margin-top: 8px;
}

/* 题目计数器 */
.question-counter {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
}

.question-current {
  font-weight: 600;
  color: #1e293b;
}

.question-total {
  color: #64748b;
}

.question-dots {
  display: flex;
  gap: 8px;
  margin-left: auto;
}

/* 题目区域 */
.question-area {
  margin-bottom: 32px;
}

.question-type {
  display: inline-block;
  padding: 4px 12px;
  background: #f1f5f9;
  border-radius: 20px;
  font-size: 12px;
  color: #64748b;
  margin-bottom: 16px;
}

.question-text {
  font-size: 18px;
  font-weight: 500;
  color: #1e293b;
  margin-bottom: 24px;
  line-height: 1.6;
}

.question-options {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: #f8fafc;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
  border: 2px solid transparent;
}

.option:hover {
  background: #f1f5f9;
}

.option.selected {
  background: #dbeafe;
  border-color: #3b82f6;
}

.option input[type="radio"] {
  display: none;
}

.option-label {
  font-size: 16px;
  color: #1e293b;
}

/* 考试导航 */
.exam-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
}

/* 认证页面 */
.auth-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f8fafc;
  padding: 24px;
}

.auth-card {
  background: white;
  border-radius: 16px;
  padding: 48px;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.auth-card h1 {
  font-size: 28px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 32px;
  text-align: center;
}

.form-group {
  margin-bottom: 24px;
}

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 500;
  color: #374151;
  margin-bottom: 8px;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  font-size: 16px;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: #4f46e5;
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.auth-links {
  text-align: center;
  margin-top: 24px;
}

.auth-links a {
  color: #4f46e5;
  text-decoration: none;
}

.auth-links a:hover {
  text-decoration: underline;
}

/* 广告容器 */
.ad-container {
  margin-top: 32px;
  padding: 16px;
  background: #f9fafb;
  border-radius: 12px;
  text-align: center;
  border: 1px solid #e2e8f0;
}

.ad-label {
  font-size: 10px;
  color: #9ca3af;
  margin-bottom: 8px;
}

/* 响应式设计 */
@media (max-width: 1024px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .exam-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s;
  }
  
  .sidebar.active {
    transform: translateX(0);
  }
  
  .main-content {
    margin-left: 0;
    padding: 24px 16px;
  }
  
  .top-bar {
    flex-direction: column;
    gap: 24px;
    align-items: flex-start;
  }
  
  .top-bar-right {
    width: 100%;
  }
  
  .search-box {
    flex: 1;
  }
  
  .search-box input {
    width: 100%;
  }
  
  .stats-grid {
    grid-template-columns: 1fr;
  }
  
  .exam-grid {
    grid-template-columns: 1fr;
  }
  
  .modal {
    width: 95%;
    margin: 16px;
  }
  
  .timer-display {
    font-size: 36px;
  }
  
  .question-text {
    font-size: 16px;
  }
  
  .option-label {
    font-size: 14px;
  }
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: #1e293b;
  cursor: pointer;
  padding: 8px;
}

@media (max-width: 768px) {
  .mobile-menu-btn {
    display: block;
    position: fixed;
    top: 16px;
    left: 16px;
    z-index: 1001;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  }
}

/* 加载状态 */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 48px;
}

.loading-spinner {
  width: 40px;
  height: 40px;
  border: 4px solid #e2e8f0;
  border-top-color: #4f46e5;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* 空状态 */
.empty-state {
  text-align: center;
  padding: 48px;
  color: #64748b;
}

.empty-state svg {
  margin-bottom: 16px;
  color: #94a3b8;
}

.empty-state h3 {
  font-size: 18px;
  font-weight: 600;
  color: #374151;
  margin-bottom: 8px;
}

.empty-state p {
  font-size: 14px;
  max-width: 400px;
  margin: 0 auto;
}

/* 工具类 */
.hidden {
  display: none !important;
}

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.mt-4 {
  margin-top: 16px;
}

.mb-4 {
  margin-bottom: 16px;
}

.p-4 {
  padding: 16px;
}