:root {
  --primary-color: #4285f4;
  --primary-dark: #3367d6;
  --primary-light: #8ab4f8;
  --secondary-color: #34a853;
  --warning-color: #fbbc04;
  --danger-color: #ea4335;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --text-light: #80868b;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e8eaed;
  --border-color: #dadce0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.1);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.15);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.2);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --sidebar-width: 260px;
  --header-height: 60px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  font-size: 14px;
  line-height: 1.5;
  color: var(--text-primary);
  background-color: var(--bg-secondary);
}

.hidden { display: none !important; }

.loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background: var(--bg-primary);
}

.loader {
  width: 40px;
  height: 40px;
  border: 3px solid var(--bg-tertiary);
  border-top-color: var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

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

.login-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 20px;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
}

.login-card {
  background: var(--bg-primary);
  padding: 40px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  text-align: center;
  max-width: 400px;
  width: 100%;
}

.login-header {
  margin-bottom: 30px;
}

.school-icon {
  font-size: 48px;
  display: block;
  margin-bottom: 10px;
}

.login-header h1 {
  font-size: 24px;
  margin-bottom: 8px;
}

.login-header p {
  color: var(--text-secondary);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border: none;
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
}

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

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

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

.btn-secondary:hover {
  background: var(--bg-tertiary);
}

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

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

.btn-large {
  padding: 14px 28px;
  font-size: 16px;
  width: 100%;
}

.btn-icon {
  background: none;
  border: none;
  font-size: 20px;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius-md);
}

.btn-icon:hover {
  background: var(--bg-tertiary);
}

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

.error-message {
  color: var(--danger-color);
  margin-top: 16px;
  padding: 12px;
  background: #fce8e6;
  border-radius: var(--radius-md);
}

.dashboard {
  display: grid;
  grid-template-areas:
    "sidebar header"
    "sidebar main";
  grid-template-columns: var(--sidebar-width) 1fr;
  grid-template-rows: var(--header-height) 1fr;
  min-height: 100vh;
}

.header {
  grid-area: header;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.notification-badge {
  position: absolute;
  top: 2px;
  right: 2px;
  background: var(--danger-color);
  color: white;
  font-size: 10px;
  padding: 2px 6px;
  border-radius: 10px;
}

.user-menu {
  position: relative;
}

.dropdown {
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  min-width: 200px;
  z-index: 200;
}

.dropdown-header {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
}

.dropdown-item {
  display: block;
  padding: 10px 16px;
  color: var(--text-primary);
  text-decoration: none;
  cursor: pointer;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-size: 14px;
}

.dropdown-item:hover {
  background: var(--bg-secondary);
}

.dropdown hr {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 4px 0;
}

.sidebar {
  grid-area: sidebar;
  background: var(--bg-primary);
  border-right: 1px solid var(--border-color);
  overflow-y: auto;
}

.sidebar-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-header .school-icon {
  font-size: 28px;
}

.school-name {
  font-size: 18px;
  font-weight: 600;
}

.nav-menu {
  list-style: none;
  padding: 12px 0;
}

.nav-item {
  margin: 2px 8px;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: all 0.2s;
}

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

.nav-link.active {
  background: var(--primary-light);
  color: var(--primary-dark);
}

.nav-link-icon {
  font-size: 18px;
  width: 24px;
  text-align: center;
}

.nav-section-title {
  padding: 16px 16px 8px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-light);
  letter-spacing: 0.5px;
}

.main-content {
  grid-area: main;
  padding: 24px;
  overflow-y: auto;
}

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

.content-header h2 {
  font-size: 24px;
  font-weight: 500;
}

.card {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  margin-bottom: 24px;
}

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

.card-title {
  font-size: 16px;
  font-weight: 500;
}

.card-body {
  padding: 20px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-sm);
}

.stat-icon {
  font-size: 32px;
  margin-bottom: 12px;
}

.stat-value {
  font-size: 28px;
  font-weight: 600;
  margin-bottom: 4px;
}

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

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

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

th {
  background: var(--bg-secondary);
  font-weight: 500;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
}

tr:hover {
  background: var(--bg-secondary);
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 12px;
  font-weight: 500;
}

.badge-success {
  background: #e6f4ea;
  color: #137333;
}

.badge-warning {
  background: #fef7e0;
  color: #b45309;
}

.badge-danger {
  background: #fce8e6;
  color: #c5221f;
}

.badge-info {
  background: #e8f0fe;
  color: #1967d2;
}

.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: block;
  margin-bottom: 6px;
  font-weight: 500;
  font-size: 13px;
}

.form-control {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 14px;
  transition: border-color 0.2s;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.2);
}

.form-control::placeholder {
  color: var(--text-light);
}

select.form-control {
  cursor: pointer;
}

.form-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.form-actions {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--border-color);
}

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
}

.modal {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  max-width: 500px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
}

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

.modal-title {
  font-size: 18px;
  font-weight: 500;
}

.modal-close {
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  color: var(--text-secondary);
}

.modal-body {
  padding: 20px;
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  padding: 16px 20px;
  border-top: 1px solid var(--border-color);
}

.search-box {
  position: relative;
  margin-bottom: 20px;
}

.search-input {
  width: 100%;
  padding: 10px 12px 10px 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 14px;
}

.search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-light);
}

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 20px;
}

.pagination-btn {
  padding: 8px 12px;
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  cursor: pointer;
}

.pagination-btn:hover {
  background: var(--bg-secondary);
}

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

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

.toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  padding: 12px 20px;
  background: var(--text-primary);
  color: white;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 2000;
  animation: slideIn 0.3s ease;
}

.toast-success {
  background: var(--secondary-color);
}

.toast-error {
  background: var(--danger-color);
}

@keyframes slideIn {
  from {
    transform: translateY(100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.children-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.child-card {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-sm);
}

.child-card-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

.child-avatar {
  width: 50px;
  height: 50px;
  background: var(--primary-light);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
}

.child-info h3 {
  font-size: 16px;
  margin-bottom: 4px;
}

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

.attendance-bar {
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: 4px;
  margin-top: 8px;
  overflow: hidden;
}

.attendance-fill {
  height: 100%;
  background: var(--secondary-color);
  border-radius: 4px;
}

.attendance-stats {
  display: flex;
  justify-content: space-between;
  margin-top: 12px;
  font-size: 13px;
  color: var(--text-secondary);
}

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

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

.empty-state h3 {
  font-size: 18px;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.empty-state p {
  margin-bottom: 20px;
}

.tabs {
  display: flex;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 20px;
}

.tab {
  padding: 12px 20px;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 14px;
  color: var(--text-secondary);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}

.tab:hover {
  color: var(--text-primary);
}

.tab.active {
  color: var(--primary-color);
  border-bottom-color: var(--primary-color);
}

@media (max-width: 768px) {
  .dashboard {
    grid-template-columns: 1fr;
    grid-template-areas:
      "header"
      "main";
  }

  .sidebar {
    position: fixed;
    left: -100%;
    top: 0;
    height: 100vh;
    width: var(--sidebar-width);
    z-index: 300;
    transition: left 0.3s;
  }

  .sidebar.open {
    left: 0;
  }

  .sidebar-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 250;
  }

  .menu-toggle {
    display: block;
  }

  .content-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }

  .children-grid {
    grid-template-columns: 1fr;
  }
}

@media print {
  .sidebar, .header, .btn, .nav-menu {
    display: none !important;
  }
  
  .main-content {
    padding: 0;
  }
  
  .card {
    box-shadow: none;
    border: 1px solid var(--border-color);
  }
}