Pegá esto al final de tu CSS.
Código:
/* alignments */
.center {text-align: center;}
img.center, img[align="center"] {display: block;margin-left: auto;margin-right: auto;}
.alignleft {float: left;}
img.alignleft, img[align="left"] {float:left;margin: 2px 10px 5px 0px;}
.alignright {float: right;}
img.alignright, img[align="right"] {float:right;margin: 2px 0px 5px 10px;}
.clear {clear:both;}
hr.clear {clear:both;visibility: hidden;margin: 0px;padding: 0px;height:0px;}
.rightalign {float:right;}
.leftalign {float:left;}