body {
    margin: 0;
    padding: 0;
    margin-left:auto;
    margin-right:auto;
}

@media screen and (min-width: 900px) {
    body {
        width: 900px;
    }
}

@media screen and (max-width: 899px) {
    body {
        width: 100%;
    }
}

.pad {
    padding: 10px;
}

@media all and (max-width: 727px) {
        #adbig { display: none; }
        table.tgrid td{
			border: solid 1px black;
			padding: 1px;
			font-size:90%;
		}
		table.tgrid th{
			border: solid 1px black;
			padding: 1px;
			font-size:90%;
		} 
}
@media (min-width: 728px) {
        #adsmall { display: none; }       
}