mydiv.css

html,
body {
    background-color: rgb(21, 61, 102);
    color: white;
    width: 98%;
    padding: 0;
    margin: 0;
}

#header {
    padding: 5px;
}

#root {
    margin: 0;
    padding: 5px;
    width: 97%;
    float: left;
    margin-left: 10px;
    background-color: rgb(197, 200, 207);
    border: 2px solid darkslategray;
    border-radius: 10px;
}

#root>div:nth-child(1) {
    float: left;
    width: 96%;
    height: 420px;
    margin-top: 5px;
    margin-left: 10px;
    background-color: rgb(244, 245, 245);
    border: 2px solid darkslategray;
    border-radius: 10px;
    padding-left: 6px;
    padding-right: 6px;
    padding-top: 6px;
    padding-bottom: 6px;
}

#root>div:nth-child(2) {
    float: left;
    width: 96%;
    height: 250px;
    margin-top: 5px;
    margin-left: 10px;
    background-color: rgb(244, 245, 245);
    border: 2px solid darkslategray;
    border-radius: 10px;
    padding-left: 6px;
    padding-right: 6px;
    padding-top: 6px;
    padding-bottom: 6px;
}

#footer {
    clear: both;
    text-align: center;
    padding: 5px;
}