shul display screen mockup

HTML

<div id="header" class="rounded-corners">Header</div>
<div id="col1-row1">col1-row1</div>
<div id="col1-row2">col1-row2</div>
<div id="col2-row1" class="rounded-corners">col2-row1</div>
<div id="col2-row2">col2-row2</div>
<div id="col3-row1">col3-row1</div>
<div id="col3-row2">col3-row2</div>

CSS

div {
    position: absolute;
    border: 1px solid gray;
    margin: 10px;
}

#header {
    left: 55px;
    top: 0px;
    width: 120%;
    height: 75px;
    text-align: center;
}

#col1-row1 {
    left: 0px;
    top: 85px;
    width: 150px;
    height: 75px;
}

#col1-row2 {
    left: 0px;
    top: 170px;
    width: 150px;
    height: 500px;
}

#col2-row1 {
    left: 160px;
    top: 85px;
    width: 500px;
    height: 75px;
    
}

#col2-row2 {
    left: 160px;
    top: 170px;
    width: 500px;
    height: 500px;
    overflow-y: scroll;
}

#col3-row1 {
    left: 680px;
    top: 85px;
    width: 150px;
    height: 75px;
}

#col3-row2 {
    left: 680px;
    top: 170px;
    width: 150px;
    height: 500px;
    overflow-y: scroll;
}

.rounded-corners {
     -moz-border-radius: 20px;
    -webkit-border-radius: 20px;
    -khtml-border-radius: 20px;
    border-radius: 20px;
}