:root {
  --primary: #4f8cff;
  --primary-dark: #3a6fd4;
  --success: #52c41a;
  --warning: #faad14;
  --danger: #ff4d4f;
  --bg: #f5f7fa;
  --card-bg: #fff;
  --text: #1a1a2e;
  --text-secondary: #8492a6;
  --border: #e8ecf1;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ============ 登录页 ============ */
.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: 20px;
}

.login-card {
  background: #fff;
  border-radius: 20px;
  padding: 40px;
  width: 100%;
  max-width: 420px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.login-card h1 {
  text-align: center;
  font-size: 24px;
  margin-bottom: 8px;
  color: var(--text);
}

.login-card .subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 32px;
}

.role-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
  background: var(--bg);
  border-radius: 10px;
  padding: 4px;
}

.role-tab {
  flex: 1;
  padding: 10px;
  text-align: center;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all 0.2s;
  border: none;
  background: transparent;
}

.role-tab.active {
  background: #fff;
  color: var(--primary);
  box-shadow: var(--shadow);
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 6px;
  font-weight: 500;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 14px;
  border: 2px solid var(--border);
  border-radius: 10px;
  font-size: 14px;
  color: var(--text);
  transition: border-color 0.2s;
  outline: none;
  font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  border-color: var(--primary);
}

.form-group textarea {
  resize: vertical;
  min-height: 100px;
}

.btn {
  padding: 12px 24px;
  border: none;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: inherit;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
}

.btn-block {
  width: 100%;
  justify-content: center;
}

.btn-outline {
  background: #fff;
  color: var(--text);
  border: 2px solid var(--border);
}

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

.btn-danger {
  background: #fff;
  color: var(--danger);
  border: 2px solid #ffccc7;
}

.btn-danger:hover {
  background: var(--danger);
  color: #fff;
}

.btn-success {
  background: var(--success);
  color: #fff;
}

.toggle-text {
  text-align: center;
  margin-top: 16px;
  font-size: 14px;
  color: var(--text-secondary);
}

.toggle-text a {
  color: var(--primary);
  cursor: pointer;
  text-decoration: none;
  font-weight: 500;
}

.login-error {
  background: #fff2f0;
  border: 1px solid #ffccc7;
  color: var(--danger);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 13px;
  margin-bottom: 16px;
  display: none;
}

.login-error.show {
  display: block;
}

.demo-hint {
  margin-top: 20px;
  padding: 12px;
  background: #f0f5ff;
  border-radius: 8px;
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.8;
}

.demo-hint b {
  color: var(--primary);
}

/* ============ 主布局 ============ */
.app-layout {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 240px;
  background: #fff;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  position: fixed;
  height: 100vh;
  z-index: 100;
}

.sidebar-logo {
  padding: 24px 20px;
  font-size: 18px;
  font-weight: 700;
  color: var(--primary);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 8px;
}

.sidebar-menu {
  flex: 1;
  padding: 16px 12px;
  overflow-y: auto;
}

.menu-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 14px;
  color: var(--text-secondary);
  transition: all 0.2s;
  margin-bottom: 4px;
}

.menu-item:hover {
  background: var(--bg);
  color: var(--text);
}

.menu-item.active {
  background: var(--primary);
  color: #fff;
}

.menu-item .icon {
  font-size: 18px;
  width: 22px;
  text-align: center;
}

.sidebar-user {
  padding: 16px 20px;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.sidebar-user .avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 600;
}

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

.sidebar-user .name {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.sidebar-user .role-tag {
  font-size: 12px;
  color: var(--text-secondary);
}

.logout-btn {
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 18px;
  padding: 4px;
}

.main-content {
  flex: 1;
  margin-left: 240px;
  padding: 24px 32px;
}

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

.page-title {
  font-size: 22px;
  font-weight: 700;
}

/* ============ 统计卡片 ============ */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 16px;
}

.stat-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
}

.stat-info .stat-value {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
}

.stat-info .stat-label {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ============ 卡片 ============ */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  margin-bottom: 16px;
}

.card-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.card-title {
  font-size: 16px;
  font-weight: 600;
}

.card-body {
  padding: 20px;
}

/* ============ 排课列表 ============ */
.schedule-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px;
  border-radius: 10px;
  background: var(--bg);
  margin-bottom: 12px;
  transition: all 0.2s;
  cursor: pointer;
}

.schedule-item:hover {
  background: #eef4ff;
}

.schedule-date {
  text-align: center;
  min-width: 56px;
}

.schedule-date .day {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary);
}

.schedule-date .month {
  font-size: 12px;
  color: var(--text-secondary);
}

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

.schedule-info .title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 4px;
}

.schedule-info .meta {
  font-size: 13px;
  color: var(--text-secondary);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.schedule-badge {
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
}

.badge-scheduled {
  background: #e6f7ff;
  color: #1890ff;
}

.badge-completed {
  background: #f6ffed;
  color: #52c41a;
}

.badge-cancelled {
  background: #fff2f0;
  color: #ff4d4f;
}

/* ============ 学生卡片 ============ */
.student-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}

.student-card {
  background: #fff;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  transition: all 0.2s;
}

.student-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-lg);
}

.student-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.student-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 600;
}

.student-name {
  font-size: 16px;
  font-weight: 600;
}

.student-meta {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ============ 评语区域 ============ */
.evaluation-card {
  background: #fff;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
}

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

.evaluation-student {
  display: flex;
  align-items: center;
  gap: 10px;
}

.evaluation-content {
  color: var(--text);
  line-height: 1.8;
  font-size: 14px;
  margin-bottom: 12px;
}

.evaluation-meta {
  font-size: 12px;
  color: var(--text-secondary);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.rating-stars {
  color: var(--warning);
  font-size: 16px;
  letter-spacing: 2px;
}

.reply-section {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
}

.reply-item {
  background: #f0f5ff;
  border-radius: 10px;
  padding: 12px 16px;
  margin-bottom: 8px;
}

.reply-item .reply-author {
  font-size: 13px;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 4px;
}

.reply-item .reply-content {
  font-size: 14px;
  color: var(--text);
  line-height: 1.6;
}

.reply-item .reply-time {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ============ 模态框 ============ */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
}

.modal {
  background: #fff;
  border-radius: 16px;
  width: 100%;
  max-width: 560px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
}

.modal-large {
  max-width: 720px;
}

.modal-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 18px;
  font-weight: 600;
}

.modal-close {
  background: none;
  border: none;
  font-size: 24px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
}

.modal-close:hover {
  background: var(--bg);
}

.modal-body {
  padding: 24px;
}

.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: flex-end;
  gap: 12px;
}

/* ============ 表单 ============ */
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.student-select-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 10px;
  margin-top: 8px;
}

.student-checkbox {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  border: 2px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
  font-size: 14px;
}

.student-checkbox:hover {
  border-color: var(--primary);
}

.student-checkbox.checked {
  border-color: var(--primary);
  background: #f0f5ff;
}

.student-checkbox input {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
}

/* ============ 空状态 ============ */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-secondary);
}

.empty-state .empty-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.empty-state .empty-text {
  font-size: 15px;
}

/* ============ 标签 ============ */
.tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 500;
}

.tag-blue { background: #e6f7ff; color: #1890ff; }
.tag-green { background: #f6ffed; color: #52c41a; }
.tag-orange { background: #fff7e6; color: #fa8c16; }

/* ============ 日历视图 ============ */
.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
}

.calendar-header {
  text-align: center;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  padding: 8px 0;
}

.calendar-cell {
  min-height: 80px;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.2s;
}

.calendar-cell:hover {
  border-color: var(--primary);
}

.calendar-cell.other-month {
  background: #fafafa;
  color: #ccc;
}

.calendar-cell.today {
  border-color: var(--primary);
  border-width: 2px;
}

.calendar-cell .day-num {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 4px;
}

.calendar-event {
  background: var(--primary);
  color: #fff;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 11px;
  margin-bottom: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ============ Toast ============ */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text);
  color: #fff;
  padding: 12px 24px;
  border-radius: 10px;
  font-size: 14px;
  z-index: 2000;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
}

/* ============ 响应式 ============ */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s;
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .main-content {
    margin-left: 0;
    padding: 16px;
  }
  .form-row {
    grid-template-columns: 1fr;
  }
  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* 加载动画 */
.loading {
  text-align: center;
  padding: 40px;
  color: var(--text-secondary);
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 12px;
}

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

/* 复选框组 */
.checkbox-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.checkbox-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
}

.checkbox-item input {
  accent-color: var(--primary);
  width: 16px;
  height: 16px;
}

/* 评分输入 */
.rating-input {
  display: flex;
  gap: 4px;
  font-size: 28px;
}

.rating-input span {
  cursor: pointer;
  color: #d9d9d9;
  transition: color 0.2s;
}

.rating-input span.active {
  color: var(--warning);
}

.rating-input span:hover {
  color: var(--warning);
}