:root {
  --primary: #4f46e5;
  --primary-light: #818cf8;
  --primary-bg: #eef2ff;
  --danger: #ef4444;
  --warning: #f59e0b;
  --success: #10b981;
  --bg: #f5f7fa;
  --card-bg: #ffffff;
  --border: #e5e7eb;
  --text: #1f2937;
  --text-secondary: #6b7280;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  --radius: 8px;
  --nav-width: 1200px;
}

* { 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);
  line-height: 1.5;
}

#app {
  max-width: 1400px;
  margin: 0 auto;
  min-height: 100vh;
}

/* Header */
.app-header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.app-title {
  font-size: 20px;
  font-weight: 700;
}

.app-subtitle {
  font-size: 13px;
  color: var(--text-secondary);
  margin-left: 12px;
}

.header-left { display: flex; align-items: baseline; }

/* Tabs */
.tab-nav {
  display: flex;
  gap: 4px;
  padding: 12px 24px 0;
  background: var(--card-bg);
  border-bottom: 2px solid var(--border);
}

.tab-btn {
  padding: 10px 20px;
  border: none;
  background: none;
  cursor: pointer;
  font-size: 14px;
  color: var(--text-secondary);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all 0.2s;
  position: relative;
}

.tab-btn:hover { color: var(--primary); }
.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  font-weight: 600;
}

.badge {
  background: var(--danger);
  color: white;
  font-size: 11px;
  padding: 1px 6px;
  border-radius: 10px;
  margin-left: 4px;
}

/* Buttons */
.btn {
  padding: 8px 16px;
  border: 1px solid var(--border);
  background: var(--card-bg);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 14px;
  transition: all 0.2s;
}

.btn:hover { background: var(--bg); }
.btn-primary {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}
.btn-primary:hover { background: var(--primary-light); }
.btn-sm { padding: 4px 10px; font-size: 13px; }

/* Import Panel */
.import-panel { padding: 40px 24px; }

.import-hero {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.import-icon { font-size: 64px; margin-bottom: 16px; }
.import-hero h2 { font-size: 24px; margin-bottom: 8px; }
.import-hero p { color: var(--text-secondary); margin-bottom: 24px; }

.upload-area {
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 48px 24px;
  transition: all 0.3s;
  cursor: pointer;
  background: var(--card-bg);
}

.upload-area:hover, .upload-area.dragging {
  border-color: var(--primary);
  background: var(--primary-bg);
}

.upload-icon { font-size: 40px; margin-bottom: 12px; }
.upload-hint { color: var(--text-secondary); font-size: 13px; margin: 8px 0; }

.import-note {
  margin-top: 32px;
  text-align: left;
  background: var(--primary-bg);
  padding: 16px 20px;
  border-radius: var(--radius);
  font-size: 13px;
}
.import-note h4 { margin-bottom: 8px; font-size: 14px; }
.import-note p { color: var(--text-secondary); }

/* Preview */
.preview-panel { padding: 24px; }
.preview-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}
.preview-stats { display: flex; gap: 16px; font-size: 13px; color: var(--text-secondary); }

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  background: var(--card-bg);
  border-radius: var(--radius);
  overflow: hidden;
}

.data-table th {
  background: var(--bg);
  padding: 10px 12px;
  text-align: left;
  font-weight: 600;
  white-space: nowrap;
  border-bottom: 1px solid var(--border);
}

.data-table td {
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  max-width: 160px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.preview-more {
  text-align: center;
  padding: 12px;
  color: var(--text-secondary);
  font-size: 13px;
}

.preview-actions {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
  margin-top: 20px;
}

/* Timetable */
.timetable-panel { padding: 16px 24px; }

.tt-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  padding: 12px 16px;
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.tt-toolbar-left { display: flex; align-items: center; gap: 8px; font-size: 14px; }
.tt-toolbar-right { display: flex; align-items: center; gap: 8px; }
.zoom-label { font-size: 13px; color: var(--text-secondary); min-width: 40px; text-align: center; }

.group-select {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
  background: var(--card-bg);
}

.tt-container { overflow-x: auto; }

.tt-grid {
  display: grid;
  grid-template-columns: 100px repeat(7, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  min-width: 900px;
}

.tt-cell {
  background: var(--card-bg);
  padding: 8px;
  min-height: 80px;
}

.tt-header {
  background: var(--primary);
  color: white;
  text-align: center;
  font-weight: 600;
  padding: 12px 8px;
  min-height: auto;
  font-size: 14px;
}

.tt-corner {
  background: var(--primary);
  min-height: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
}

.tt-time {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  min-height: 100px;
}

.period-label { font-weight: 600; font-size: 13px; }
.period-time { font-size: 11px; color: var(--text-secondary); margin-top: 4px; }

.tt-slot {
  position: relative;
  min-height: 100px;
  transition: background 0.2s;
}

.tt-slot.drag-over {
  background: var(--primary-bg);
  outline: 2px dashed var(--primary);
  outline-offset: -2px;
}

/* Course Card */
.course-card {
  padding: 6px 8px;
  border-radius: 4px;
  border-left: 3px solid;
  margin-bottom: 4px;
  cursor: grab;
  transition: all 0.15s;
  font-size: 12px;
}

.course-card:hover {
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
  transform: translateY(-1px);
}

.course-card:active { cursor: grabbing; }
.course-name { font-weight: 600; line-height: 1.3; }
.course-teacher { color: var(--text-secondary); margin-top: 2px; }
.course-weeks { color: var(--primary); font-size: 11px; margin-top: 2px; }
.course-room { color: var(--text-secondary); font-size: 11px; }

/* Validate */
.validate-panel { padding: 24px; }
.val-toolbar { margin-bottom: 20px; }

.val-section { margin-bottom: 24px; }
.val-section h3 {
  font-size: 16px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.issue-card {
  padding: 12px 16px;
  border-radius: var(--radius);
  margin-bottom: 8px;
  border-left: 3px solid;
}

.issue-card.issue-error {
  background: #fef2f2;
  border-left-color: var(--danger);
}

.issue-card.issue-warning {
  background: #fffbeb;
  border-left-color: var(--warning);
}

.issue-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}

.issue-teacher, .issue-course { font-weight: 600; }
.issue-time, .issue-hours { font-size: 13px; color: var(--text-secondary); }
.issue-courses { display: flex; gap: 8px; flex-wrap: wrap; font-size: 13px; }
.issue-course { background: rgba(0,0,0,0.05); padding: 2px 8px; border-radius: 4px; }

.val-ok {
  text-align: center;
  padding: 48px;
  font-size: 18px;
  color: var(--success);
}

/* Export */
.export-panel { padding: 24px; }
.export-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 24px;
}

.export-card {
  background: var(--card-bg);
  padding: 24px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-align: center;
}

.export-icon { font-size: 40px; margin-bottom: 12px; }
.export-card h3 { margin-bottom: 8px; }
.export-card p { color: var(--text-secondary); font-size: 13px; margin-bottom: 16px; }

.teacher-export-controls {
  display: flex;
  gap: 8px;
  justify-content: center;
  align-items: center;
}

.teacher-preview {
  margin-top: 24px;
}

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal {
  background: var(--card-bg);
  border-radius: 12px;
  width: 480px;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: 0 20px 40px rgba(0,0,0,0.2);
}

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

.modal-header h3 { font-size: 16px; }

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

.modal-body { padding: 20px; }
.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  padding: 16px 20px;
  border-top: 1px solid var(--border);
}

.form-group { margin-bottom: 16px; }
.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--text-secondary);
}

.form-input {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
  transition: border-color 0.2s;
}

.form-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-bg);
}

.form-row { display: flex; gap: 12px; }
.form-row .form-group { flex: 1; }

/* Week Editor */
.week-editor { display: flex; flex-wrap: wrap; gap: 4px; }

.week-dot {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 4px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.15s;
  user-select: none;
}

.week-dot:hover { border-color: var(--primary); }
.week-dot.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* Teacher timetable for export */
.teacher-tt-export {
  background: white;
  padding: 24px;
  font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', sans-serif;
}

.teacher-tt-title {
  text-align: center;
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid #333;
}

.teacher-tt-grid {
  width: 100%;
  border-collapse: collapse;
}

.teacher-tt-grid th,
.teacher-tt-grid td {
  border: 1px solid #333;
  padding: 8px;
  text-align: center;
  font-size: 12px;
  min-width: 100px;
  vertical-align: top;
}

.teacher-tt-grid th {
  background: var(--primary);
  color: white;
  font-weight: 600;
  padding: 10px 8px;
}

.teacher-tt-grid .time-col {
  background: #f3f4f6;
  font-weight: 600;
  white-space: nowrap;
  min-width: 80px;
}

.teacher-tt-course {
  background: var(--primary-bg);
  border-radius: 4px;
  padding: 4px;
  margin: 2px 0;
  font-size: 11px;
  text-align: left;
}

.teacher-tt-other {
  background: #f3f4f6;
  border-radius: 4px;
  padding: 4px;
  margin: 2px 0;
  height: 40px;
}
/* Login Page */
.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-card {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 40px;
  width: 400px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

.login-header {
  text-align: center;
  margin-bottom: 32px;
}

.login-icon { font-size: 48px; margin-bottom: 12px; }
.login-header h1 { font-size: 22px; margin-bottom: 4px; }
.login-header p { color: var(--text-secondary); font-size: 14px; }

.login-error {
  color: var(--danger);
  font-size: 13px;
  margin: 8px 0;
  text-align: center;
}

.btn-block { width: 100%; margin-top: 16px; padding: 12px; font-size: 16px; }

/* User Info */
.user-info {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
}

.user-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
}

.user-role {
  display: inline-block;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 10px;
  font-weight: 600;
}

.role-admin {
  background: #fef3c7;
  color: #d97706;
}

.role-teacher {
  background: #dbeafe;
  color: #2563eb;
}

.school-select {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
  background: var(--card-bg);
  margin-left: 12px;
}

.header-badge {
  font-size: 12px;
  color: var(--text-secondary);
  margin-left: 12px;
  background: var(--bg);
  padding: 2px 10px;
  border-radius: 10px;
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 80px 24px;
}

.empty-icon { font-size: 64px; margin-bottom: 16px; }
.empty-state h3 { font-size: 18px; margin-bottom: 8px; }
.empty-state p { color: var(--text-secondary); font-size: 14px; }

/* Modal Large */
.modal-lg { width: 800px; }
.modal-lg .modal-body { max-height: 60vh; overflow-y: auto; }

.preview-stats {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

/* Settings */
.settings-panel { padding: 24px; }

.settings-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.settings-section {
  background: var(--card-bg);
  padding: 20px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.settings-section h3 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.add-user-form {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.add-user-form h4 { font-size: 14px; margin-bottom: 12px; }

.add-user-form .form-row {
  display: flex;
  gap: 8px;
  align-items: center;
}

.add-user-form .form-input {
  padding: 6px 10px;
  font-size: 13px;
}