:root {
            --primary-color: #4285f4;
            --secondary-color: #34a853;
            --accent-color: #ea4335;
            --light-bg: #f8f9fa;
            --dark-text: #202124;
        }
        body {
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
            color: #343a40;
            min-height: 100vh;
        }
        .container {
            max-width: 1500px;
            background: white;
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            padding: 25px;
           /* margin-top: 30px;
            margin-bottom: 30px; */
        }
        .header {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            padding: 25px;
            border-radius: 10px;
            margin-bottom: 30px;
            text-align: center;
        }
        .header h1 {
            font-weight: 700;
            margin-bottom: 10px;
            font-size: 2.5rem;
        }
        .header p {
            font-size: 1.2rem;
            opacity: 0.9;
            margin-bottom: 0;
        }
        .card {
            border: none;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
            margin-bottom: 25px;
            transition: transform 0.3s ease;
        }
        .card:hover {
            transform: translateY(-5px);
        }
        .card-header {
            background: linear-gradient(135deg, var(--primary-color), #5b7cbf);
            color: white;
            border-radius: 10px 10px 0 0 !important;
            font-weight: 600;
            padding: 15px 20px;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .table-container {
            padding: 20px;
            overflow-x: auto;
        }
        table {
            border-collapse: separate;
            border-spacing: 0;
            width: 100%;
        }
        th {
            background-color: #f1f5f9;
            color: var(--dark-text);
            font-weight: 600;
            padding: 12px 15px;
            position: sticky;
            top: 0;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
            cursor: help;
            position: relative;
        }
        td {
            padding: 12px 15px;
            border-bottom: 1px solid #e9ecef;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        tr:nth-child(even) {
            background-color: #f8f9fa;
        }
        tr:hover {
            background-color: #e9ecef;
        }
        .dataTables_wrapper {
            padding: 0 10px;
        }
        .dataTables_filter input {
            border: 1px solid #ced4da;
            border-radius: 5px;
            padding: 5px 10px;
            margin-left: 10px;
        }
        .dataTables_length select {
            border: 1px solid #ced4da;
            border-radius: 5px;
            padding: 5px;
        }
        .stats-box {
            background: white;
            border-radius: 10px;
            padding: 20px;
            text-align: center;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
            margin-bottom: 25px;
        }
        .stats-box i {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 15px;
        }
        .stats-box h3 {
            font-size: 2rem;
            font-weight: 700;
            color: var(--dark-text);
            margin-bottom: 5px;
        }
        .stats-box p {
            color: #6c757d;
            margin-bottom: 0;
        }
        .footer {
            text-align: center;
            color: #6c757d;
            font-size: 9px;
        }
        .compatibility-note {
            background-color: #e7f3ff;
            border-left: 4px solid var(--primary-color);
            padding: 15px;
            margin: 20px 0;
            border-radius: 4px;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .error-alert {
            background-color: #f8d7da;
            border-left: 4px solid #dc3545;
            padding: 15px;
            margin: 20px 0;
            border-radius: 4px;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .success-alert {
            background-color: #d4edda;
            border-left: 4px solid #28a745;
            padding: 15px;
            margin: 20px 0;
            border-radius: 4px;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .dashboard-header {
            margin: 30px 0 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid #e9ecef;
            color: var(--dark-text);
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .graph-card {
            height: 50%;
        }
        .graph-card .card-body {
            padding: 20px;
        }
        .chart-container {
            position: relative;
            height: 250px;
            width: 100%;
        }
        .stat-card {
            text-align: center;
            padding: 15px;
            background-color: #f8f9fa;
            border-radius: 8px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.05);
        }
        .stat-card i {
            font-size: 2rem;
            color: var(--primary-color);
            margin-bottom: 10px;
        }
        .stat-card h3 {
            font-size: 1.8rem;
            font-weight: 700;
            margin-bottom: 5px;
            color: var(--dark-text);
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .stat-card p {
            color: #6c757d;
            margin-bottom: 0;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        @media (max-width: 768px) {
            .header h1 {
                font-size: 2rem;
            }
            .header p {
                font-size: 1rem;
            }
            .container {
                padding: 15px;
            }
            .graph-card {
                height: auto;
            }
        }
        .refresh-btn {
            background: var(--primary-color);
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 5px;
            cursor: pointer;
            transition: background 0.3s;
            font-family: 'Roboto UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        .refresh-btn:hover {
            background: #3367d6;
        }
        .instructions {
            background-color: #f8f9fa;
            border-radius: 8px;
            padding: 20px;
            margin-bottom: 25px;
        }
        /* DataTable specific styles */
        .dt-buttons {
            margin-bottom: 10px;
        }
        .dt-button {
            background-color: #f8f9fa !important;
            border: 1px solid #dee2e6 !important;
            color: #212529 !important;
            border-radius: 4px !important;
            padding: 5px 10px !important;
            margin-right: 5px !important;
        }
        .dt-button:hover {
            background-color: #e9ecef !important;
        }
        /* Tooltip styles */
        .tooltip {
            position: absolute;
            background-color: #333;
            color: white;
            padding: 8px 12px;
            border-radius: 4px;
            font-size: 14px;
            z-index: 1000;
            max-width: 300px;
            word-wrap: break-word;
            box-shadow: 0 3px 6px rgba(0,0,0,0.16);
        }
        .column-abbr {
            font-weight: bold;
        }
        .student-analytics {
            margin-top: 30px;
        }
        .search-highlight {
            background-color: #fff3cd;
            font-weight: bold;
        }
        .student-info-card {
            background: linear-gradient(135deg, #6c5ce7, #a29bfe);
            color: white;
            border-radius: 10px;
            padding: 20px;
            margin-bottom: 20px;
        }
        .student-detail-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 15px;
            margin-top: 15px;
        }
        .student-detail-item {
            background: rgba(255, 255, 255, 0.2);
            padding: 10px;
            border-radius: 8px;
            text-align: center;
        }
        .student-detail-value {
            font-size: 1.5rem;
            font-weight: bold;
            margin-bottom: 5px;
        }
        .student-detail-label {
            font-size: 0.9rem;
            opacity: 0.9;
        }
        .attendance-matrix {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
            gap: 10px;
            margin-top: 15px;
        }
        .attendance-item {
            background: rgba(255, 255, 255, 0.2);
            padding: 10px;
            border-radius: 8px;
            text-align: center;
        }
        .attendance-value {
            font-size: 1.2rem;
            font-weight: bold;
        }
        .attendance-label {
            font-size: 0.8rem;
            opacity: 0.9;
        }
        .highlight-row {
            background-color: #fff3cd !important;
        }
        /* Add to your existing CSS */
.text-success {
    color: #28a745 !important;
}
.text-danger {
    color: #dc3545 !important;
}
.fa-thumbs-up, .fa-thumbs-down {
    font-size: 1.2rem;
    margin-top: 5px;
}
.sheet-selector {
            background-color: white;
            padding: 1rem;
            border-radius: 10px;
            margin-bottom: 1.5rem;
            box-shadow: 0 2px 10px rgba(0,0,0,0.08);
        }

        .sheet-radio {
            margin-right: 0.5rem;
        }

        .sheet-label {
            display: inline-block;
            padding: 0.5rem 1rem;
            margin: 0.25rem;
            background-color: #edf2f7;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .sheet-label:hover {
            background-color: #e2e8f0;
        }

        .sheet-radio:checked + .sheet-label {
            background-color: var(--primary-color);
            color: white;
        }

        .current-sheet {
            font-weight: bold;
            color: var(--primary-color);
            margin-left: 1rem;
        }