body {
            background-color: #f8f9fa;
            padding: 20px 0;
        }

        .lesson-card {
            background: white;
            border-left: 4px solid #007bff;
            margin-bottom: 30px;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        }

        .lesson-card.pair-programming {
            border-left-color: #28a745;
        }

        .lesson-card.practice {
            border-left-color: #ffc107;
        }

        .lesson-title {
            font-size: 1.3rem;
            font-weight: bold;
            margin-bottom: 15px;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .badge-lesson {
            font-size: 0.85rem;
            padding: 0.5rem 0.75rem;
        }

        .problem-section {
            background-color: #f0f7ff;
            padding: 15px;
            border-radius: 5px;
            margin-bottom: 15px;
        }

        .code-section {
            background-color: #282c34;
            color: #abb2bf;
            padding: 15px;
            border-radius: 5px;
            font-family: 'Courier New', monospace;
            font-size: 0.9rem;
            overflow-x: auto;
            margin-bottom: 15px;
            border: 2px dashed #ff6b6b;
        }

        .output-section {
            background-color: #e8f5e9;
            padding: 15px;
            border-radius: 5px;
            border-left: 3px solid #4caf50;
            margin-bottom: 15px;
        }

        .interactive-area {
            background-color: #fff3cd;
            padding: 20px;
            border-radius: 5px;
            margin-bottom: 15px;
        }

        .btn-primary-custom {
            background-color: #007bff;
            border: none;
            padding: 10px 20px;
            border-radius: 5px;
            color: white;
            cursor: pointer;
            font-weight: 600;
            margin-right: 10px;
        }

        .btn-primary-custom:hover {
            background-color: #0056b3;
        }

        input, select, textarea {
            padding: 8px 12px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 1rem;
        }

        .list-item {
            background-color: white;
            padding: 10px 15px;
            margin: 5px 0;
            border-left: 3px solid #007bff;
            display: flex;
            justify-content: space-between;
            align-items: center;
            border-radius: 10px;
            max-width: 300px;
        }

        .remove-btn {
            background-color: #dc3545;
            color: white;
            border: none;
            padding: 5px 10px;
            border-radius: 3px;
            cursor: pointer;
            font-size: 0.85rem;
        }

        .result-message {
            padding: 15px;
            border-radius: 5px;
            margin-top: 10px;
            font-weight: 600;
        }

        .success {
            background-color: #d4edda;
            color: #155724;
            border: 1px solid #c3e6cb;
        }

        .warning {
            background-color: #fff3cd;
            color: #856404;
            border: 1px solid #ffeeba;
        }

        .error {
            background-color: #f8d7da;
            color: #721c24;
            border: 1px solid #f5c6cb;
        }

        .hint {
            background-color: #e7f3ff;
            border-left: 4px solid #2196F3;
            padding: 10px 15px;
            margin-top: 10px;
            border-radius: 3px;
            font-size: 0.95rem;
        }

        .key-concept {
            background-color: #fce4ec;
            border-left: 4px solid #e91e63;
            padding: 12px 15px;
            margin: 15px 0;
            border-radius: 3px;
        }

        .code-template {
            background-color: #f5f5f5;
            padding: 15px;
            border-left: 4px solid #ff9800;
            border-radius: 5px;
            margin-bottom: 15px;
            font-family: 'Courier New', monospace;
        }

        .todo-card{
            padding: 10px;
            margin: 8px 0;
            border-radius: 8px;
            color: white;
        }

        .high{
            background-color: red;
        }

        .medium{
            background-color: orange;
        }

        .low{
            background-color: green;
        }



        @media (max-width: 768px) {
            .lesson-card {
                margin-bottom: 20px;
            }

            .container-lg {
                padding: 0 10px;
            }
        }