* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        :root {
            --primary: #4361ee;
            --secondary: #3a0ca3;
            --accent: #4cc9f0;
            --light: #f8f9fa;
            --dark: #212529;
            --success: #4bb543;
            --warning: #ffcc00;
            --danger: #dc3545;
            --gray: #6c757d;
            --border-radius: 12px;
            --box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
            --transition: all 0.3s ease;
        }

        body {
            background-color: #f5f7fb;
            color: var(--dark);
            line-height: 1.6;
        }

        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 20px;
        }

        header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 20px 0;
            margin-bottom: 30px;
            border-bottom: 1px solid rgba(0, 0, 0, 0.1);
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary);
        }

        .logo i {
            font-size: 1.8rem;
        }

        .user-profile {
            display: flex;
            align-items: center;
            gap: 10px;
            background: white;
            padding: 8px 15px;
            border-radius: 50px;
            box-shadow: var(--box-shadow);
        }

        .user-profile img {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            object-fit: cover;
        }

        .dashboard-title {
            font-size: 2rem;
            margin-bottom: 20px;
            color: var(--secondary);
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .dashboard-title i {
            color: var(--accent);
        }

        .dashboard-subtitle {
            color: var(--gray);
            margin-bottom: 30px;
            font-size: 1.1rem;
        }

        .controls {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 25px;
            flex-wrap: wrap;
            gap: 15px;
        }

        .time-filters {
            display: flex;
            background: white;
            border-radius: var(--border-radius);
            padding: 5px;
            box-shadow: var(--box-shadow);
        }

        .time-filter {
            padding: 10px 20px;
            cursor: pointer;
            border-radius: 8px;
            font-weight: 600;
            transition: var(--transition);
            text-align: center;
        }

        .time-filter.active {
            background: var(--primary);
            color: white;
        }

        .export-actions {
            display: flex;
            gap: 15px;
        }

        .btn {
            padding: 10px 20px;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            font-weight: 600;
            transition: var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }

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

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

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

        .btn-outline {
            background: transparent;
            border: 1px solid var(--primary);
            color: var(--primary);
        }

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

        .card {
            background: white;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            padding: 25px;
            margin-bottom: 25px;
            transition: var(--transition);
        }

        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }

        .card-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            padding-bottom: 15px;
            border-bottom: 1px solid rgba(0, 0, 0, 0.1);
        }

        .card-title {
            font-size: 1.4rem;
            font-weight: 600;
            color: var(--secondary);
        }

        .card-subtitle {
            color: var(--gray);
            font-size: 0.9rem;
        }

        .stats-container {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
        }

        .stat-card {
            background: white;
            border-radius: var(--border-radius);
            padding: 25px;
            box-shadow: var(--box-shadow);
            display: flex;
            align-items: center;
            gap: 20px;
        }

        .stat-icon {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            color: white;
        }

        .stat-1 .stat-icon {
            background: linear-gradient(135deg, #4361ee, #3a0ca3);
        }

        .stat-2 .stat-icon {
            background: linear-gradient(135deg, #4cc9f0, #4895ef);
        }

        .stat-3 .stat-icon {
            background: linear-gradient(135deg, #f72585, #b5179e);
        }

        .stat-4 .stat-icon {
            background: linear-gradient(135deg, #4bb543, #2e8b57);
        }

        .stat-info h3 {
            font-size: 1.8rem;
            margin-bottom: 5px;
        }

        .stat-info p {
            color: var(--gray);
            font-size: 0.9rem;
        }

        .chart-container {
            height: 300px;
            margin-top: 20px;
            position: relative;
        }

        .grid-2 {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 25px;
        }

        .grid-3 {
            display: grid;
            grid-template-columns: 1fr 1fr 1fr;
            gap: 25px;
        }

        .feedback-list {
            max-height: 400px;
            overflow-y: auto;
        }

        .feedback-item {
            background: #f8f9fa;
            border-radius: 8px;
            padding: 15px;
            margin-bottom: 15px;
            transition: var(--transition);
        }

        .feedback-item:hover {
            background: #e9ecef;
            transform: translateX(5px);
        }

        .feedback-header {
            display: flex;
            justify-content: space-between;
            margin-bottom: 10px;
        }

        .feedback-student {
            font-weight: 600;
            color: var(--secondary);
        }

        .feedback-course {
            color: var(--primary);
            font-weight: 500;
        }

        .feedback-rating {
            display: flex;
            align-items: center;
            gap: 5px;
            color: var(--warning);
            font-weight: 600;
        }

        .feedback-comment {
            color: var(--gray);
            font-size: 0.95rem;
            line-height: 1.5;
        }

        .feedback-date {
            font-size: 0.8rem;
            color: var(--gray);
            margin-top: 8px;
        }

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

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

        th, td {
            padding: 15px;
            text-align: left;
            border-bottom: 1px solid #eee;
        }

        th {
            background-color: #f8f9fa;
            font-weight: 600;
            color: var(--secondary);
        }

        tr:hover {
            background-color: #f8f9fa;
        }

        .progress-bar {
            height: 8px;
            background: #e9ecef;
            border-radius: 4px;
            overflow: hidden;
            margin-top: 5px;
        }

        .progress {
            height: 100%;
            border-radius: 4px;
        }

        .progress-5 { width: 100%; background: var(--success); }
        .progress-4 { width: 80%; background: #8ac926; }
        .progress-3 { width: 60%; background: var(--warning); }
        .progress-2 { width: 40%; background: #ff9e00; }
        .progress-1 { width: 20%; background: var(--danger); }

        .rating-distribution {
            display: flex;
            flex-direction: column;
            gap: 10px;
            margin-top: 15px;
        }

        .rating-item {
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .rating-stars {
            display: flex;
            gap: 2px;
            color: var(--warning);
        }

        .rating-count {
            font-weight: 600;
            min-width: 30px;
        }

        .rating-percent {
            color: var(--gray);
            font-size: 0.9rem;
        }

        .empty-state {
            text-align: center;
            padding: 40px 20px;
            color: var(--gray);
        }

        .empty-state i {
            font-size: 3rem;
            margin-bottom: 15px;
            color: #ddd;
        }

        .filter-section {
            background: white;
            border-radius: var(--border-radius);
            padding: 20px;
            margin-bottom: 25px;
            box-shadow: var(--box-shadow);
        }

        .filter-row {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }

        .filter-group {
            flex: 1;
            min-width: 200px;
        }

        .filter-label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
        }

        .filter-select {
            width: 100%;
            padding: 10px 15px;
            border: 1px solid #ddd;
            border-radius: 8px;
            font-size: 1rem;
            transition: var(--transition);
        }

        .filter-select:focus {
            border-color: var(--accent);
            box-shadow: 0 0 0 3px rgba(76, 201, 240, 0.3);
            outline: none;
        }

        @media (max-width: 1024px) {
            .grid-2, .grid-3 {
                grid-template-columns: 1fr;
            }
        }

        @media (max-width: 768px) {
            .controls {
                flex-direction: column;
                align-items: flex-start;
            }

            .time-filters {
                width: 100%;
                justify-content: space-between;
            }

            .export-actions {
                width: 100%;
                justify-content: flex-end;
                margin-top: 15px;
            }

            .filter-row {
                flex-direction: column;
                gap: 15px;
            }

            .user-profile span {
                display: none;
            }
        }

        @media (max-width: 480px) {
            .time-filters {
                flex-direction: column;
            }

            .time-filter {
                margin-bottom: 5px;
            }

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