.mx_GenericErrorPage { width: 100%; height: 100%; background-color: #fff; } .mx_GenericErrorPage_box { position: absolute; top: 0; bottom: 0; left: 0; right: 0; margin: auto; width: 500px; height: 200px; border: 1px solid #f22; padding: 10px 10px 20px; background-color: #fcc; }