#mybox1 {
    margin: 10px;
    border: 10px solid #000;
    padding: 10px;
}

#child_left {
    margin: 10px;
    border: 10px solid blueviolet;
    padding: 10px;
    float: left;
    width: 200px;
    background-color: #9855c5;
}

#child_middle {
    float: left;
    border: 5px solid #1f1ab6;
    background-color: #13ee22;
}

#child_right {
    margin: 10px;
    border: 10px solid blueviolet;
    padding: 10px;
    float: right;
    background-color: #ff00cc;
}