* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background-color: #f8f9fa;
            color: #333;
            line-height: 1.6;
        }
        
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
        }
        
        header {
            margin-bottom: 30px;
            padding-bottom: 20px;
            border-bottom: 1px solid #eaeaea;
        }
        
        .main-title {
            font-size: 2.2rem;
            color: #2c3e50;
            margin-bottom: 10px;
        }
        
        .intro {
            color: #555;
            font-size: 1.1rem;
            margin-bottom: 15px;
        }
        
        .freeform-intro {
            background-color: #f0f7ff;
            border-left: 4px solid #4a90e2;
            padding: 15px;
            margin-bottom: 20px;
            border-radius: 0 5px 5px 0;
        }
        
        .freeform-intro h3 {
            color: #2c3e50;
            margin-bottom: 8px;
        }
        
        .freeform-intro p {
            color: #555;
        }
        
        .search-section {
            background-color: white;
            padding: 25px;
            border-radius: 8px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
            margin-bottom: 30px;
        }
        
        .section-title {
            color: #2c3e50;
            margin-bottom: 20px;
            font-size: 1.5rem;
        }
        
        .search-box {
            display: flex;
            margin-bottom: 15px;
        }
        
        .search-box input {
            flex: 1;
            padding: 12px 15px;
            border: 1px solid #ddd;
            border-radius: 4px 0 0 4px;
            font-size: 1rem;
        }
        
        .search-btn {
            background-color: #4a90e2;
            color: white;
            border: none;
            padding: 0 20px;
            border-radius: 0 4px 4px 0;
            cursor: pointer;
            font-size: 1rem;
            transition: background-color 0.3s;
        }
        
        .search-btn:hover {
            background-color: #3a7bc8;
        }
        
        .categories {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }
        
        .category-tag {
            background-color: #eef5ff;
            color: #4a90e2;
            padding: 8px 15px;
            border-radius: 20px;
            font-size: 0.9rem;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .category-tag:hover, .category-tag.active {
            background-color: #4a90e2;
            color: white;
        }
        
        .exercises-section {
            background-color: white;
            padding: 25px;
            border-radius: 8px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
            margin-bottom: 30px;
        }
        
        .exercise-list {
            display: flex;
            flex-direction: column;
            gap: 25px;
        }
        
        .exercise-item {
            padding: 20px;
            border: 1px solid #eaeaea;
            border-radius: 6px;
            transition: box-shadow 0.3s;
        }
        
        .exercise-item:hover {
            box-shadow: 0 6px 15px rgba(0, 0, 0, 0.08);
            border-color: #d0e1ff;
        }
        
        .exercise-title {
            color: #2c3e50;
            font-size: 1.3rem;
            margin-bottom: 10px;
        }
        
        .exercise-source {
            color: #4a90e2;
            font-weight: 600;
            margin-bottom: 15px;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        
        .exercise-source i {
            font-size: 0.9rem;
        }
        
        .exercise-question {
            color: #555;
            margin-bottom: 15px;
            line-height: 1.7;
        }
        
        .exercise-action {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .practice-btn {
    background-color: #c82333;
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 4px;
            cursor: pointer;
            font-size: 1rem;
            transition: background-color 0.3s;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        
        .practice-btn:hover {
            background-color: #219653;
        }
        
        .practice-count {
            color: #7f8c8d;
            font-size: 0.9rem;
            display: flex;
            align-items: center;
            gap: 5px;
        }
        
        footer {
            text-align: center;
            padding: 20px;
            color: #7f8c8d;
            font-size: 0.9rem;
            border-top: 1px solid #eaeaea;
            margin-top: 30px;
        }
            .footer-section {
            flex: 1;
            min-width: 250px;
        }
        
        .footer-section h3 {
            font-size: 1.3rem;
            margin-bottom: 20px;
            color: #ffd166;
        }

        .footer-section p {
            margin-bottom: 15px;
        }
        
        .footer-section a {
            color: #e9f2ff;
            text-decoration: none;
        }
        
        .footer-section a:hover {
            color: #ffd166;
            text-decoration: underline;
        }
        
        .copyright {
            text-align: center;
            margin-top: 40px;
            padding-top: 20px;
            border-top: 1px solid #1a6dcc;
            color: #ccc;
            font-size: 0.9rem;
        }

        
        @media (max-width: 768px) {
            .container {
                padding: 15px;
            }
            
            .main-title {
                font-size: 1.8rem;
            }
            
            .search-box {
                flex-direction: column;
            }
            
            .search-box input {
                border-radius: 4px;
                margin-bottom: 10px;
            }
            
            .search-btn {
                border-radius: 4px;
                padding: 12px;
            }
            
            .exercise-action {
                flex-direction: column;
                align-items: flex-start;
                gap: 15px;
            }
        }