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

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
            color: #fff;
            min-height: 100vh;
            position: relative;
            overflow-x: hidden;
        }

        body::before {
            content: "";
            position: fixed;
            width: 600px;
            height: 600px;
            background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
            border-radius: 50%;
            top: -300px;
            right: -300px;
            pointer-events: none;
            will-change: transform;
        }

        @keyframes float {
            0%, 100% { transform: translate(0, 0) scale(1); }
            50% { transform: translate(40px, 40px) scale(1.1); }
        }

        /* Header */
        .fixed-header {
            background: rgba(255, 255, 255, 0.15);
            backdrop-filter: blur(20px);
            width: 100%;
            text-align: center;
            padding: 24px 20px;
            font-size: 2rem;
            font-weight: 800;
            letter-spacing: -0.5px;
            box-shadow: 0 4px 30px rgba(0,0,0,0.2);
            position: sticky;
            top: 0;
            z-index: 1000;
            border-bottom: 1px solid rgba(255,255,255,0.2);
            animation: slideDown 0.6s ease;
        }

        @keyframes slideDown {
            from { opacity: 0; transform: translateY(-20px); }
            to { opacity: 1; transform: translateY(0); }
        }

        /* Main Container */
        .welcome-container {
            width: 95%;
            max-width: 1400px;
            margin: 30px auto;
            position: relative;
            z-index: 10;
            animation: fadeIn 0.8s ease;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }

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

        .back-btn {
            background: rgba(255, 255, 255, 0.2);
            backdrop-filter: blur(10px);
            border: 2px solid rgba(255, 255, 255, 0.3);
            color: white;
            padding: 12px 24px;
            font-size: 1rem;
            font-weight: 700;
            border-radius: 12px;
            cursor: pointer;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .back-btn:hover {
            transform: translateY(-2px);
            background: rgba(255, 255, 255, 0.3);
            box-shadow: 0 8px 20px rgba(0,0,0,0.2);
        }

        .class-badge {
            background: linear-gradient(135deg, #ff6b6b, #ff8e53);
            padding: 12px 28px;
            border-radius: 12px;
            font-weight: 700;
            font-size: 1.1rem;
            box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
            animation: pulse 2s infinite;
        }

        @keyframes pulse {
            0%, 100% { transform: scale(1); }
            50% { transform: scale(1.05); }
        }

        /* Filter Section */
        .filter-section {
            background: rgba(255, 255, 255, 0.15);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            padding: 25px;
            margin-bottom: 30px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
            border: 1px solid rgba(255, 255, 255, 0.2);
            animation: slideUp 0.7s ease;
        }

        @keyframes slideUp {
            from { opacity: 0; transform: translateY(30px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .filter-title {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: 20px;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .filter-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 15px;
            margin-bottom: 20px;
        }

        .filter-group {
            display: flex;
            flex-direction: column;
            gap: 8px;
        }

        .filter-group label {
            font-weight: 600;
            font-size: 0.9rem;
            opacity: 0.95;
        }

        .filter-group select,
        .filter-group input {
            padding: 12px 16px;
            border-radius: 10px;
            border: 2px solid rgba(255, 255, 255, 0.3);
            background: rgba(255, 255, 255, 0.25);
            backdrop-filter: blur(10px);
            color: white;
            font-size: 1rem;
            font-weight: 600;
            transition: all 0.3s ease;
            font-family: 'Inter', sans-serif;
        }

        .filter-group select:focus,
        .filter-group input:focus {
            outline: none;
            border-color: rgba(255, 255, 255, 0.6);
            background: rgba(255, 255, 255, 0.35);
            transform: translateY(-2px);
        }

        .filter-group select option {
            background: #764ba2;
            color: white;
        }

        .filter-group input::placeholder {
            color: rgba(255, 255, 255, 0.7);
        }

        .filter-actions {
            display: flex;
            gap: 12px;
            flex-wrap: wrap;
        }

        .filter-btn {
            padding: 12px 28px;
            border-radius: 10px;
            border: none;
            font-weight: 700;
            font-size: 1rem;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .apply-filter {
            background: linear-gradient(135deg, #10b981, #059669);
            color: white;
            box-shadow: 0 4px 15px rgba(16, 185, 129, 0.4);
        }

        .apply-filter:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(16, 185, 129, 0.5);
        }

        .reset-filter {
            background: rgba(255, 255, 255, 0.25);
            backdrop-filter: blur(10px);
            color: white;
            border: 2px solid rgba(255, 255, 255, 0.3);
        }

        .reset-filter:hover {
            background: rgba(255, 255, 255, 0.35);
            transform: translateY(-2px);
        }

        /* Results Info */
        .results-info {
            background: rgba(255, 255, 255, 0.2);
            backdrop-filter: blur(10px);
            padding: 15px 20px;
            border-radius: 12px;
            margin-bottom: 25px;
            font-weight: 600;
            display: flex;
            justify-content: space-between;
            align-items: center;
            animation: fadeIn 0.5s ease;
        }

        /* Tests Grid */
        .tests-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
            gap: 25px;
            animation: fadeIn 1s ease;
        }

        .test-card {
            background: rgba(255, 255, 255, 0.98);
            color: #2d3748;
            border-radius: 20px;
            padding: 25px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            border: 1px solid rgba(255, 255, 255, 0.3);
            position: relative;
            will-change: transform;
            contain: layout style paint;
        }

        .test-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
        }

        .test-header {
            display: flex;
            justify-content: space-between;
            align-items: flex-start;
            margin-bottom: 15px;
            gap: 15px;
        }

        .test-title {
            color: #764ba2;
            font-size: 1.3rem;
            font-weight: 800;
            line-height: 1.3;
            flex: 1;
        }

        .test-subject {
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            padding: 6px 14px;
            border-radius: 8px;
            font-size: 0.85rem;
            font-weight: 700;
            white-space: nowrap;
        }

        .test-meta {
            background: #f7fafc;
            border-radius: 12px;
            padding: 12px;
            margin-bottom: 15px;
        }

        .test-meta p {
            margin: 6px 0;
            font-size: 0.95rem;
            color: #4a5568;
            font-weight: 600;
        }

        .test-meta strong {
            color: #2d3748;
        }

        .test-date {
            display: flex;
            align-items: center;
            gap: 6px;
            color: #667eea;
            font-weight: 700;
        }

        .test-preview {
            margin: 15px 0;
            border-radius: 12px;
            overflow: hidden;
            border: 2px solid #e2e8f0;
            background: #f7fafc;
        }

        .pdf-viewer {
            width: 100%;
            height: 300px;
            border: none;
            transform: translateZ(0);
            -webkit-transform: translateZ(0);
        }

        .test-image {
            width: 100%;
            height: auto;
            max-height: 300px;
            object-fit: contain;
            display: block;
            transform: translateZ(0);
            -webkit-transform: translateZ(0);
        }

        .image-fallback {
            padding: 40px;
            text-align: center;
            color: #718096;
        }

        .test-actions {
            display: flex;
            gap: 10px;
        }

        .download-btn {
            flex: 1;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            text-decoration: none;
            font-weight: 700;
            padding: 14px 20px;
            border-radius: 12px;
            text-align: center;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(118, 75, 162, 0.3);
        }

        .download-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 20px rgba(118, 75, 162, 0.5);
        }

        /* Loading & Empty States */
        .loading, .no-tests {
            text-align: center;
            padding: 60px 20px;
            font-size: 1.2rem;
            font-weight: 600;
            background: rgba(255, 255, 255, 0.15);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            animation: pulse 1.5s infinite;
        }

        .no-tests {
            animation: fadeIn 0.5s ease;
        }

        .error-message {
            text-align: center;
            padding: 40px;
            background: rgba(239, 68, 68, 0.2);
            backdrop-filter: blur(10px);
            border-radius: 16px;
            border: 2px solid rgba(239, 68, 68, 0.3);
        }

        .retry-btn {
            margin-top: 15px;
            padding: 12px 28px;
            background: white;
            color: #ef4444;
            border: none;
            border-radius: 10px;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .retry-btn:hover {
            transform: scale(1.05);
        }

        /* Responsive */
        @media (max-width: 768px) {
            .fixed-header {
                font-size: 1.5rem;
                padding: 18px 15px;
            }

            .tests-grid {
                grid-template-columns: 1fr;
            }

            .filter-grid {
                grid-template-columns: 1fr;
            }

            .top-controls {
                flex-direction: column;
                align-items: stretch;
            }

            .results-info {
                flex-direction: column;
                gap: 10px;
                text-align: center;
            }
        }

        @media (min-width: 1200px) {
            .tests-grid {
                grid-template-columns: repeat(3, 1fr);
            }
        }