/* ========== Admin Panel CSS — Light Green Clean Theme ========== */
:root {
  --primary: #059669;
  --primary-hover: #047857;
  --primary-light: #D1FAE5;
  --primary-bg: #ECFDF5;
  --sidebar-bg: #022C22;
  --sidebar-hover: #064E3B;
  --sidebar-active: #059669;
  --surface: #FFFFFF;
  --bg: #F0FDF4;
  --text: #064E3B;
  --text-secondary: #475569;
  --text-muted: #94A3B8;
  --border: #D1FAE5;
  --border-light: #ECFDF5;
  --success: #16A34A;
  --success-light: #DCFCE7;
  --danger: #DC2626;
  --danger-light: #FEE2E2;
  --warning: #F59E0B;
  --warning-light: #FEF3C7;
  --info: #0891B2;
  --info-light: #CFFAFE;
  --shadow-sm: 0 1px 2px rgba(2, 44, 34, 0.04);
  --shadow: 0 1px 3px rgba(2, 44, 34, 0.06), 0 1px 2px rgba(2, 44, 34, 0.04);
  --shadow-md: 0 4px 6px rgba(2, 44, 34, 0.05), 0 2px 4px rgba(2, 44, 34, 0.04);
  --radius-sm: 6px;
  --radius: 8px;
  --radius-lg: 12px;
  --transition: 150ms ease;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-hover); }

/* ========== Layout ========== */
.admin-layout { display: flex; min-height: 100vh; }

/* ========== Sidebar ========== */
.sidebar {
  width: 240px;
  background: var(--sidebar-bg);
  color: #fff;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  overflow-y: auto;
  z-index: 50;
  display: flex;
  flex-direction: column;
}

.sidebar .logo {
  padding: 24px 20px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.sidebar .logo h2 {
  font-size: 17px;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.5px;
}
.sidebar .logo p {
  font-size: 11px;
  color: rgba(255,255,255,0.35);
  margin-top: 4px;
  letter-spacing: 0.3px;
}

.sidebar .nav { padding: 12px 8px; flex: 1; }
.sidebar .nav a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  margin-bottom: 2px;
  color: rgba(255,255,255,0.55);
  font-size: 13.5px;
  border-radius: var(--radius);
  transition: all var(--transition);
  position: relative;
}
.sidebar .nav a .nav-icon {
  width: 20px; height: 20px;
  flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  opacity: 0.75;
}
.sidebar .nav a .nav-icon svg {
  width: 18px; height: 18px;
  display: block;
}
.sidebar .nav a:hover {
  color: #fff;
  background: var(--sidebar-hover);
}
.sidebar .nav a.active {
  color: #fff;
  background: var(--sidebar-active);
  font-weight: 500;
  box-shadow: 0 2px 8px rgba(5, 150, 105, 0.3);
}
.sidebar .nav a.active .nav-icon { opacity: 1; }

/* Sidebar footer */
.sidebar-footer {
  padding: 12px 16px;
  border-top: 1px solid rgba(255,255,255,0.06);
}
.sidebar-footer a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  color: rgba(255,255,255,0.4);
  font-size: 12.5px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.sidebar-footer a:hover { color: rgba(255,255,255,0.7); background: var(--sidebar-hover); }
.sidebar-footer a .nav-icon {
  width: 18px; height: 18px;
  flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  opacity: 0.7;
}
.sidebar-footer a .nav-icon svg {
  width: 16px; height: 16px;
  display: block;
}

/* ========== Main Area ========== */
.main-area {
  margin-left: 240px;
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ========== Header ========== */
.header {
  background: var(--surface);
  padding: 0 28px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
  border-bottom: 1px solid var(--border-light);
  position: sticky;
  top: 0;
  z-index: 40;
}
.header .breadcrumb {
  font-size: 13px;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}
.header .breadcrumb::before {
  content: '';
  display: inline-block;
  width: 3px; height: 14px;
  background: var(--primary);
  border-radius: 2px;
}
.header .user-area {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 13px;
  color: var(--text-secondary);
}
.header .user-area .btn-link {
  color: var(--text-muted);
  font-size: 12.5px;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.header .user-area .btn-link:hover { color: var(--primary); background: var(--primary-bg); }
.header .user-area .btn-logout {
  padding: 6px 16px;
  background: transparent;
  color: var(--danger);
  border: 1px solid var(--danger-light);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 12.5px;
  transition: all var(--transition);
  font-family: inherit;
}
.header .user-area .btn-logout:hover {
  background: var(--danger);
  color: #fff;
}

/* ========== Content ========== */
.content { padding: 28px; flex: 1; }

/* ========== Cards ========== */
.card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  border: 1px solid var(--border-light);
}
.card-header {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.card-header h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}
.card-body { padding: 24px; }

/* ========== Stats Row ========== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}
.stat-card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border-light);
  transition: all var(--transition);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.stat-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 3px;
  background: var(--primary);
  opacity: 0;
  transition: opacity var(--transition);
}
.stat-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--border);
}
.stat-card:hover::before { opacity: 1; }
.stat-card .stat-icon {
  width: 40px; height: 40px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  margin-bottom: 12px;
  background: var(--primary-bg);
  color: var(--primary);
}
.stat-card .stat-num {
  font-size: 32px;
  font-weight: 700;
  color: var(--text);
  line-height: 1;
}
.stat-card .stat-label {
  font-size: 12.5px;
  color: var(--text-muted);
  margin-top: 6px;
}

/* ========== Tables ========== */
.table-wrap { overflow-x: auto; border-radius: var(--radius-lg); }
table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
table th, table td { padding: 12px 16px; text-align: left; }
table th {
  background: #F9FCFA;
  font-weight: 600;
  font-size: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.3px;
  white-space: nowrap;
  border-bottom: 2px solid var(--border-light);
}
table td { border-bottom: 1px solid var(--border-light); color: var(--text); }
table tbody tr { transition: background var(--transition); }
table tbody tr:hover td { background: #F9FCFA; }
table tbody tr:last-child td { border-bottom: none; }

table .actions { white-space: nowrap; display: flex; gap: 6px; }
table .actions a, table .actions button {
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  cursor: pointer;
  border: none;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: all var(--transition);
  font-family: inherit;
  font-weight: 500;
}
table .actions .btn-edit {
  background: var(--primary-bg);
  color: var(--primary);
}
table .actions .btn-edit:hover { background: var(--primary-light); }
table .actions .btn-del {
  background: var(--danger-light);
  color: var(--danger);
}
table .actions .btn-del:hover { background: #FECACA; }
table .actions .btn-view {
  background: var(--success-light);
  color: var(--success);
}

/* ========== Forms ========== */
.form-group { margin-bottom: 18px; }
.form-group label {
  display: block;
  margin-bottom: 6px;
  font-weight: 500;
  font-size: 13px;
  color: var(--text);
}
.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid #D1D5DB;
  border-radius: var(--radius);
  font-size: 14px;
  transition: all var(--transition);
  outline: none;
  background: var(--surface);
  color: var(--text);
  font-family: inherit;
}
.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(5, 150, 105, 0.1);
}
.form-group textarea { min-height: 100px; resize: vertical; }
.form-group input::placeholder { color: var(--text-muted); }
.form-actions { display: flex; gap: 12px; margin-top: 24px; }

/* ========== Buttons ========== */
.btn {
  padding: 8px 20px;
  border-radius: var(--radius);
  font-size: 13.5px;
  cursor: pointer;
  border: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all var(--transition);
  font-family: inherit;
  font-weight: 500;
  line-height: 1.4;
}
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 1px 2px rgba(5, 150, 105, 0.2); }
.btn-primary:hover { background: var(--primary-hover); box-shadow: 0 2px 4px rgba(5, 150, 105, 0.25); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #B91C1C; }
.btn-default { background: var(--surface); color: var(--text); border: 1px solid #D1D5DB; }
.btn-default:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-bg); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #15803D; }
.btn-sm { padding: 5px 12px; font-size: 12px; }
.btn-lg { padding: 10px 24px; font-size: 15px; }

/* ========== Badges ========== */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 11.5px;
  font-weight: 500;
}
.badge-green { background: var(--success-light); color: var(--success); }
.badge-red { background: var(--danger-light); color: var(--danger); }
.badge-blue { background: var(--info-light); color: var(--info); }
.badge-orange { background: var(--warning-light); color: var(--warning); }
.badge-yellow { background: #FEF3C7; color: #D97706; }

/* ========== Alerts ========== */
.alert {
  padding: 12px 16px;
  border-radius: var(--radius);
  margin-bottom: 16px;
  font-size: 13px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.alert-error {
  background: var(--danger-light);
  color: var(--danger);
  border: 1px solid #FECACA;
}
.alert-success {
  background: var(--success-light);
  color: var(--success);
  border: 1px solid #BBF7D0;
}
.alert-info {
  background: var(--info-light);
  color: var(--info);
  border: 1px solid #A5F3FC;
}

/* ========== Pagination ========== */
.pagination {
  display: flex;
  justify-content: center;
  gap: 4px;
  margin-top: 24px;
}
.pagination a, .pagination span {
  padding: 7px 14px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  border: 1px solid #D1D5DB;
  color: var(--text-secondary);
  transition: all var(--transition);
}
.pagination a:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-bg); }
.pagination .active { background: var(--primary); color: #fff; border-color: var(--primary); font-weight: 500; }
.pagination .disabled { color: #D1D5DB; cursor: not-allowed; pointer-events: none; }

/* ========== Login Page ========== */
.login-page {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: linear-gradient(135deg, #022C22 0%, #065F46 40%, #059669 100%);
  padding: 20px;
}
.login-box {
  background: var(--surface);
  border-radius: 16px;
  padding: 44px 40px;
  width: 420px;
  box-shadow: 0 20px 60px rgba(2, 44, 34, 0.3);
}
.login-box .login-logo {
  text-align: center;
  margin-bottom: 12px;
}
.login-box .login-logo .logo-icon {
  width: 56px; height: 56px;
  background: var(--primary-bg);
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  margin-bottom: 12px;
}
.login-box h1 {
  text-align: center;
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}
.login-box .subtitle {
  text-align: center;
  color: var(--text-muted);
  margin-bottom: 32px;
  font-size: 13.5px;
}
.login-box .btn-primary {
  width: 100%;
  justify-content: center;
  padding: 11px;
  font-size: 15px;
  border-radius: var(--radius);
}
.login-error {
  padding: 10px 16px;
  background: var(--danger-light);
  color: var(--danger);
  border-radius: var(--radius);
  margin-bottom: 16px;
  font-size: 13px;
  text-align: center;
  border: 1px solid #FECACA;
}
.login-footer {
  text-align: center;
  margin-top: 20px;
  color: var(--text-muted);
  font-size: 12px;
}

/* ========== Filter Bar ========== */
.filter-bar {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
  flex-wrap: wrap;
  align-items: center;
}
.filter-bar input, .filter-bar select {
  padding: 8px 12px;
  border: 1px solid #D1D5DB;
  border-radius: var(--radius);
  font-size: 13px;
  outline: none;
  background: var(--surface);
  transition: all var(--transition);
  font-family: inherit;
}
.filter-bar input:focus, .filter-bar select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(5, 150, 105, 0.1);
}
.filter-bar input { width: 180px; }

/* ========== Empty State ========== */
.empty { text-align: center; padding: 60px 0; color: var(--text-muted); }
.empty .empty-icon { font-size: 44px; margin-bottom: 12px; opacity: 0.5; }
.empty p { font-size: 14px; }

/* ========== Schedule Grid ========== */
.schedule-grid {
  display: grid;
  grid-template-columns: 70px repeat(7, 1fr);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
}
.schedule-cell {
  padding: 10px 6px;
  border-right: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
  font-size: 12px;
  min-height: 48px;
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
}
.schedule-cell.header {
  background: #F9FCFA;
  font-weight: 600;
  font-size: 13px;
  color: var(--text-secondary);
}
.schedule-cell.time-label {
  background: #F9FCFA;
  font-weight: 500;
  font-size: 11px;
  color: var(--text-muted);
}
.schedule-cell.has-course {
  background: var(--primary-bg);
  color: var(--primary);
  font-weight: 500;
  flex-direction: column;
  cursor: pointer;
  transition: background var(--transition);
}
.schedule-cell.has-course:hover { background: var(--primary-light); }

/* ========== Modal ========== */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(2, 44, 34, 0.5);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 150ms ease;
}
.modal {
  background: var(--surface);
  border-radius: var(--radius-lg);
  width: 520px;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: 0 20px 60px rgba(2, 44, 34, 0.2);
  animation: slideUp 200ms ease;
}
.modal-header {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.modal-header h3 { font-size: 16px; font-weight: 600; }
.modal-close {
  background: none;
  border: none;
  font-size: 20px;
  cursor: pointer;
  color: var(--text-muted);
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  line-height: 1;
}
.modal-close:hover { background: var(--border-light); color: var(--text); }
.modal-body { padding: 24px; }
.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border-light);
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

/* ========== Row Form ========== */
.row-form { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.row-form input, .row-form select {
  width: 100px;
  padding: 6px 8px;
  border: 1px solid #D1D5DB;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-family: inherit;
}

/* ========== Page Header ========== */
.page-header {
  margin-bottom: 24px;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}
.page-header h2 {
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 10px;
}
.page-header h2 .dot {
  width: 8px; height: 8px;
  background: var(--primary);
  border-radius: 50%;
}

/* ========== Animations ========== */
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .sidebar {
    width: 56px;
  }
  .sidebar .logo { padding: 16px 8px; }
  .sidebar .logo h2, .sidebar .logo p { display: none; }
  .sidebar .nav a { padding: 10px; justify-content: center; font-size: 14px; }
  .sidebar .nav a .label { display: none; }
  .sidebar .nav a .nav-icon { margin: 0; }
  .sidebar-footer a .label, .sidebar-footer { display: none; }
  .main-area { margin-left: 56px; }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .content { padding: 16px; }
  .login-box { width: 100%; padding: 32px 24px; }
  .page-header { flex-direction: column; gap: 12px; }
}

@media (max-width: 480px) {
  .stats-row { grid-template-columns: 1fr; }
  .filter-bar { flex-direction: column; }
  .filter-bar input { width: 100%; }
}