div {

    padding: 30px;

    border: 1px solid #ddd;

}

​

.g-children {

    text-align: center;

    cursor: pointer;

    background: #fff;

    &:hover {

        background: #eee;

    }

}

​

.g-children:focus {

    outline: none;

}

.g-father:focus-within {

    background: #fc0;

}