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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #020a54 100%);
            min-height: 100vh;
        
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
        }

        header {
            text-align: center;
            color: white;
            margin-bottom: 50px;
        }

        header h1 {
            font-size: 2.5rem;
            margin-bottom: 10px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
        }

        header p {
            font-size: 1.1rem;
            opacity: 0.9;
        }

        .filter-buttons {
            display: flex;
            justify-content: center;
            gap: 15px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }

        .filter-btn {
            padding: 10px 25px;
            border: 2px solid white;
            background: transparent;
            color: white;
            border-radius: 25px;
            cursor: pointer;
            font-size: 1rem;
            transition: all 0.3s ease;
        }

        .filter-btn:hover,
        .filter-btn.active {
            background: white;
            color: #667eea;
            transform: translateY(-2px);
        }

        .testimonials-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 30px;
            justify-content: center;
        }

        .testimonial-card {
            background: white;
            border-radius: 15px;
            padding: 30px;
            width: 350px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.3);
            transition: all 0.3s ease;
            display: flex;
            flex-direction: column;
            opacity: 0;
            animation: fadeIn 0.5s forwards;
        }

        @keyframes fadeIn {
            to {
                opacity: 1;
            }
        }

        .testimonial-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 40px rgba(0,0,0,0.4);
        }

        .testimonial-card.hide {
            display: none;
        }

        .student-header {
            display: flex;
            align-items: center;
            gap: 15px;
            margin-bottom: 20px;
        }

        .student-avatar {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            background: linear-gradient(135deg, #667eea 0%, #020a54 100%);
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 1.5rem;
            font-weight: bold;
            flex-shrink: 0;
        }

        .student-info h3 {
            color: #333;
            font-size: 1.2rem;
            margin-bottom: 5px;
        }

        .student-course {
            color: #667eea;
            font-size: 0.9rem;
            font-weight: 600;
        }

        .rating {
            margin-bottom: 15px;
        }

        .stars {
            color: #ffd700;
            font-size: 1.2rem;
        }

        .testimonial-text {
            color: #555;
            line-height: 1.6;
            flex-grow: 1;
            font-style: italic;
        }

        .testimonial-date {
            color: #999;
            font-size: 0.85rem;
            margin-top: 15px;
            text-align: right;
        }

        @media (max-width: 768px) {
            header h1 {
                font-size: 2rem;
            }

            .testimonial-card {
                width: 100%;
            }
        }