#columns
{
margin: 0 auto;
padding: 0;
width: 50%;
background-color: #fff;
float: left;
}

#columns100
{
margin: 0 auto;
padding: 0;
width: 100%;
background-color: #fff;
float: left;
margin-bottom: -2000px; 
padding-bottom: 2000px;
}

#border
{
margin: 1%;
width: 96%;
padding: 0 1%;
border: 1px dotted #000;
background-color: #ffd;
float: left;
}

#border2
{
margin: 1%;
width: 96%;
padding: 1%;
border: 1px solid #630;
background-color: #ffc;
float: left;
}