:root {
            --primary-color: #3f51b5;
            --secondary-color: #f50057;
            --success-color: #4caf50;
            --warning-color: #ff9800;
            --danger-color: #f44336;
            --light-bg: #f5f5f5;
            --card-bg: #ffffff;
            --text-color: #333333;
            --border-color: #e0e0e0;
            --public-holiday: #ffcdd2;
            --school-holiday: #c8e6c9;
            --optional-holiday: #fff9c4;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background-color: var(--light-bg);
            color: var(--text-color);
            line-height: 1.6;
        }
        
        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 20px;
        }
        
        header {
            background-color: var(--primary-color);
            color: white;
            padding: 20px;
            border-radius: 10px;
            margin-bottom: 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        }
        
        .header-left h1 {
            font-size: 1.8rem;
            margin-bottom: 5px;
        }
        
        .header-left p {
            opacity: 0.9;
            font-size: 0.9rem;
        }
        
        .header-right button {
            background-color: white;
            color: var(--primary-color);
            border: none;
            padding: 10px 20px;
            border-radius: 5px;
            cursor: pointer;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: all 0.3s;
        }
        
        .header-right button:hover {
            background-color: #f0f0f0;
            transform: translateY(-2px);
        }
        
        .tabs {
            display: flex;
            background-color: white;
            border-radius: 10px;
            overflow: hidden;
            margin-bottom: 20px;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
        }
        
        .tab {
            flex: 1;
            padding: 15px;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 600;
            border-bottom: 3px solid transparent;
        }
        
        .tab:hover {
            background-color: #f9f9f9;
        }
        
        .tab.active {
            background-color: #f0f4ff;
            border-bottom: 3px solid var(--primary-color);
            color: var(--primary-color);
        }
        
        .tab i {
            margin-right: 8px;
        }
        
        .content-section {
            background-color: var(--card-bg);
            border-radius: 10px;
            padding: 25px;
            margin-bottom: 20px;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
            display: none;
        }
        
        .content-section.active {
            display: block;
            animation: fadeIn 0.5s;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }
        
        .section-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            padding-bottom: 15px;
            border-bottom: 1px solid var(--border-color);
        }
        
        .section-header h2 {
            color: var(--primary-color);
            font-size: 1.5rem;
        }
        
        .section-actions {
            display: flex;
            gap: 10px;
        }
        
        .btn {
            padding: 10px 20px;
            border: none;
            border-radius: 5px;
            cursor: pointer;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: all 0.3s;
        }
        
        .btn-primary {
            background-color: var(--primary-color);
            color: white;
        }
        
        .btn-primary:hover {
            background-color: #303f9f;
        }
        
        .btn-secondary {
            background-color: var(--secondary-color);
            color: white;
        }
        
        .btn-secondary:hover {
            background-color: #c51162;
        }
        
        .btn-success {
            background-color: var(--success-color);
            color: white;
        }
        
        .btn-success:hover {
            background-color: #388e3c;
        }
        
        .btn-danger {
            background-color: var(--danger-color);
            color: white;
        }
        
        .btn-danger:hover {
            background-color: #d32f2f;
        }
        
        .empty-state {
            text-align: center;
            padding: 60px 20px;
            background-color: #fafafa;
            border-radius: 10px;
            border: 2px dashed var(--border-color);
        }
        
        .empty-state i {
            font-size: 3rem;
            color: #bdbdbd;
            margin-bottom: 15px;
        }
        
        .empty-state h3 {
            margin-bottom: 10px;
            color: #757575;
        }
        
        .empty-state p {
            color: #9e9e9e;
            margin-bottom: 20px;
            max-width: 500px;
            margin-left: auto;
            margin-right: auto;
        }
        
        .upload-area {
            border: 2px dashed var(--primary-color);
            border-radius: 10px;
            padding: 40px 20px;
            text-align: center;
            background-color: #f8fbff;
            margin-bottom: 20px;
        }
        
        .upload-area i {
            font-size: 3rem;
            color: var(--primary-color);
            margin-bottom: 15px;
        }
        
        .upload-area input {
            display: none;
        }
        
        .upload-area label {
            background-color: var(--primary-color);
            color: white;
            padding: 12px 25px;
            border-radius: 5px;
            cursor: pointer;
            display: inline-block;
            font-weight: 600;
        }
        
        .file-type-selector {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 20px;
        }
        
        .file-type-btn {
            padding: 10px 30px;
            background-color: #e8eaf6;
            border: none;
            border-radius: 5px;
            cursor: pointer;
            font-weight: 600;
            transition: all 0.3s;
        }
        
        .file-type-btn.active {
            background-color: var(--primary-color);
            color: white;
        }
        
        .data-summary {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
        }
        
        .summary-card {
            background-color: white;
            border-radius: 10px;
            padding: 20px;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
            border-left: 5px solid var(--primary-color);
        }
        
        .summary-card h3 {
            font-size: 1rem;
            color: #666;
            margin-bottom: 10px;
        }
        
        .summary-card .value {
            font-size: 2rem;
            font-weight: 700;
            color: var(--primary-color);
        }
        
        .holiday-cards {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
        }
        
        .holiday-card {
            padding: 20px;
            border-radius: 10px;
            position: relative;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
        }
        
        .public-holiday {
            background-color: var(--public-holiday);
            border-left: 5px solid var(--danger-color);
        }
        
        .school-holiday {
            background-color: var(--school-holiday);
            border-left: 5px solid var(--success-color);
        }
        
        .optional-holiday {
            background-color: var(--optional-holiday);
            border-left: 5px solid var(--warning-color);
        }
        
        .holiday-card h3 {
            margin-bottom: 10px;
        }
        
        .holiday-date {
            position: absolute;
            top: 20px;
            right: 20px;
            background-color: white;
            padding: 5px 10px;
            border-radius: 20px;
            font-weight: 600;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
        }
        
        .form-control {
            width: 100%;
            padding: 12px;
            border: 1px solid var(--border-color);
            border-radius: 5px;
            font-size: 1rem;
        }
        
        .form-row {
            display: flex;
            gap: 20px;
        }
        
        .form-row .form-group {
            flex: 1;
        }
        
        .view-selector {
            display: flex;
            background-color: white;
            border-radius: 5px;
            overflow: hidden;
            margin-bottom: 20px;
            width: fit-content;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
        }
        
        .view-option {
            padding: 10px 20px;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 600;
        }
        
        .view-option:hover {
            background-color: #f9f9f9;
        }
        
        .view-option.active {
            background-color: var(--primary-color);
            color: white;
        }
        
        .timetable-container {
            overflow-x: auto;
            background-color: white;
            border-radius: 10px;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
        }
        
        .timetable {
            width: 100%;
            border-collapse: collapse;
            min-width: 1000px;
        }
        
.timetable th {
    background-color: var(--primary-color);
    color: white;
    padding: 15px;
    text-align: center;
    font-weight: 600;
}

.timetable th.break-header {
    background-color: #5c6bc0;
}

.period-header-time {
    font-size: 0.72rem;
    font-weight: 500;
    opacity: 0.9;
    margin-top: 4px;
}
        
        .timetable td {
            padding: 12px;
            border: 1px solid var(--border-color);
            text-align: center;
            vertical-align: middle;
        }
        
        .period-cell {
            min-height: 70px;
            position: relative;
        }
        
        .period-subject {
            font-weight: 600;
            margin-bottom: 5px;
        }
        
.period-teacher {
    font-size: 0.85rem;
    color: #666;
}

.period-break-info {
    font-size: 0.75rem;
    color: #5f6b8a;
    margin-top: 4px;
}
        
        .period-time {
            position: absolute;
            bottom: 5px;
            right: 5px;
            font-size: 0.75rem;
            color: #999;
        }
        
        .holiday-cell {
            background-color: #ffebee;
            font-weight: 600;
            color: #d32f2f;
        }
        
.break-cell {
    background-color: #f5f5f5;
    font-weight: 600;
}

.inter-period-break-cell {
    background-color: #f7f8fd;
    min-width: 90px;
}

.break-cell-title {
    font-size: 0.75rem;
    font-weight: 700;
    color: #4e5a87;
    margin-bottom: 3px;
}

.break-cell-time {
    font-size: 0.8rem;
    font-weight: 600;
    color: #253056;
}
        
        .overlap {
            background-color: #ffebee !important;
            border: 2px solid #f44336 !important;
        }
        
.overlap-warning {
    position: absolute;
    top: 2px;
    right: 2px;
    color: #f44336;
    font-size: 0.8rem;
    cursor: help;
}
        
        .filter-controls {
            display: flex;
            gap: 15px;
            margin-bottom: 20px;
            flex-wrap: wrap;
        }
        
.filter-controls select {
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: white;
    min-width: 200px;
}

/*.filter-controls select[multiple] {
    min-height: 150px;
}*/

.overlap-progress {
    margin-bottom: 16px;
    background-color: #f8fbff;
    border: 1px solid #d9e7ff;
    border-radius: 8px;
    padding: 10px 12px;
}

.overlap-progress-label {
    font-size: 0.9rem;
    color: #3b4a7a;
    margin-bottom: 6px;
    font-weight: 600;
}

.overlap-progress-track {
    width: 100%;
    height: 8px;
    border-radius: 999px;
    background-color: #e6edff;
    overflow: hidden;
}

.overlap-progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #3f51b5, #5c6bc0);
    transition: width 0.15s linear;
}
        
        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.5);
            z-index: 1000;
            justify-content: center;
            align-items: center;
        }
        
        .modal.active {
            display: flex;
        }
        
        .modal-content {
            background-color: white;
            border-radius: 10px;
            width: 90%;
            max-width: 800px;
            max-height: 90vh;
            overflow-y: auto;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
        }
        
        .modal-header {
            padding: 20px;
            border-bottom: 1px solid var(--border-color);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .modal-header h3 {
            color: var(--primary-color);
        }
        
        .modal-body {
            padding: 20px;
        }
        
        .modal-footer {
            padding: 20px;
            border-top: 1px solid var(--border-color);
            display: flex;
            justify-content: flex-end;
            gap: 10px;
        }
        
        .close-modal {
            background: none;
            border: none;
            font-size: 1.5rem;
            cursor: pointer;
            color: #666;
        }
        
.time-setup-controls {
    background-color: #f7f9ff;
    border: 1px solid #dfe5ff;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 15px;
}

.time-setup-row {
    display: grid;
    grid-template-columns: repeat(2, minmax(220px, 1fr));
    gap: 12px;
}

.time-setup-field label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
}

.time-setup-field input {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
}

.time-period-config-grid {
    display: grid;
    gap: 10px;
}

.time-period-row {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 12px;
    display: grid;
    grid-template-columns: 70px 1fr 1fr 1fr 160px;
    gap: 10px;
    align-items: end;
    background-color: #fff;
}

.time-period-title {
    font-weight: 700;
    color: var(--primary-color);
}

.time-period-fields label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
}

.time-period-fields input,
.time-period-fields select {
    width: 100%;
    padding: 9px 10px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: #fff;
}

.time-period-preview {
    font-weight: 700;
    color: var(--primary-color);
    background-color: #f0f4ff;
    border-radius: 5px;
    padding: 10px;
    text-align: center;
}
        
        .reschedule-controls {
            display: flex;
            gap: 15px;
            margin-bottom: 20px;
            align-items: center;
        }
        
        .swap-highlight {
            background-color: #fff9c4 !important;
            border: 2px dashed #ff9800 !important;
        }
        
        footer {
            text-align: center;
            padding: 20px;
            color: #666;
            font-size: 0.9rem;
            margin-top: 30px;
            border-top: 1px solid var(--border-color);
        }
        
        @media (max-width: 768px) {
            .header-right {
                display: none;
            }
            
            .tabs {
                flex-wrap: wrap;
            }
            
            .tab {
                flex: 1 0 50%;
                padding: 12px;
            }
            
            .form-row {
                flex-direction: column;
                gap: 0;
            }
            
            .filter-controls {
                flex-direction: column;
            }
            
            .filter-controls select {
                width: 100%;
            }
            
    .time-setup-row {
        grid-template-columns: 1fr;
    }
    
    .time-period-row {
        grid-template-columns: 1fr;
        align-items: stretch;
    }
    
    .time-period-preview {
        text-align: left;
    }
}