body {
            font-family: ui-rounded, SFRounded, sans-serif;
            margin: 0;
            padding: 0;
            background-color: #f4f4f9;
            color: #333;
            line-height: 1.6;
            text-align: justify;
        }

        .container {
            max-width: 900px;
            margin: 20px auto;
            padding: 20px;
            background-color: #fff;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
        }

        h1 {
            text-align: center;
            margin-bottom: 20px;
            color: #007bff;
        }

        h2 {
            font-size: 1.8em;
            color: #333;
            margin-top: 0; 
            border-bottom: 2px solid #007bff;
        }

        .card {
            background-color: #f9f9f9;
            border: 1px solid #ddd;
            border-radius: 8px;
            padding: 15px;
            margin: 10px 0;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
            transition: background-color 0.3s;
        }
        .card h3 {
    cursor: pointer;
    position: relative;
    padding-right: 20px;
}

.card h3:after {
    content: '➕';
    font-size: 16px;
    position: absolute;
    right: 0;
    top: 0;
    transition: transform 0.3s;
}

.card h3.expanded:after {
    content: '✖️';
}

.hidden {
    display: none;
}

.expanded .hidden {
    display: block;
}

    
*/
        .hidden {
            display: none;
        }

        .navigation {
            display: flex;
            justify-content: space-between;
            margin-top: 20px;
        }

        button {
            padding: 10px 20px;
            font-size: 16px;
            cursor: pointer;
            border: none;
            border-radius: 5px;
            background-color: #007bff;
            color: white;
            transition: background-color 0.3s;
        }

        button:hover {
            background-color: #0056b3;
        }

        button:disabled {
            background-color: #ccc;
            cursor: not-allowed;
        }

        .index {
            text-align: center;
            margin-top: 20px;
        }

        .index a {
            margin: 0 5px;
            color: #007bff;
            cursor: pointer;
            text-decoration: none;
        }

        .index a:hover {
            text-decoration: underline;
        }

        @media (max-width: 600px) {
            .container {
                padding: 15px;
            }

            h1 {
                font-size: 24px;
            }

            h2 {
                font-size: 20px;
            }

            .card h3 {
                font-size: 18px;
            }

            button {
                font-size: 14px;
                padding: 8px 16px;
            }
        }

    .note {
        padding-left: 1.2em;
    }