/* the nav bar is a table with one row */
div#head-table * {
    font-size : large;
}
div#head-table {
    position : fixed;
    display: table;
    width: 100%;
    /*text-align: center;*/
    table-layout: auto;
    border-spacing: 0.5em;
}
div#head-row {
    display: table-row;
}
/* first cell of the row */
div#hierarchy-div-box {
    display: table-cell;
    vertical-align: top;
    text-align : left;
    margin : 0;
    border-width : 0;
}
/* second cell of the row */
div#child-div-box {
    display: table-cell;
    vertical-align: top;
    text-align : left;
    margin : 0px;
    border-width : 0px;
}
/* inside the second cell */
div#child-div {
    background-image : url('nav_bg.png');
    border-style : groove;
    border-color : white;
    text-align : left;
    padding : 0.5em;
    font-size : large;
}
/* third cell of the row */
div#up-div-box {
    /* cell box with max height/width because it
       contains the up-div picture */
    display: table-cell;
    vertical-align: top;
    max-height: 20px;
    width: 40px;
    border-width : 0px;
}
/* div for head comments below nav bar (outside nav bar) */
div#head-div {
    margin: 0.5em 0.5em 0.5em; 
    text-align: center;
}
/* div for foot comments below the images */
div#foot-div {
    text-align:center;
    margin : 0.5em;
}