details {
    text-align: right;
    direction: rtl;
    margin: 10px 0;
    padding: 10px;
    border: 1px solid #aaa;
    border-radius: 5px;
    background-color: #f9f9f9;
}

summary {
    font-weight: bold;
    cursor: pointer;
}

details details {
    margin-left: 20px;
    border-color: #ccc;
    background-color: #fff;
}