#my_body { margin : 0 auto ; width : 80% ; }
#my_navigation { float : left ; width : 150px ; }
#my_contents {margin-left: 150px;}
 margin-right: 10px;
 margin-left: 10px;
 line-height: 140%;
 letter-spacing: 0.1em;
 text-align: justify;
 text-justify: distribute-all-lines;
}
.float-clear {
 clear: both;
}