#sidebarContainer {
      width: 315px;
      float: right;
      border-right-width: 0;
      border-left-width: 1px;
      border-left-style: solid;

}

#mainContent {
      margin-right:350px;
      margin-left: auto;
      border-left-width: 0;
      border-right-width: 1px;
      border-right-style: solid;

}

* html #mainContent {
      margin-right: 1px;
}