/*** adding sf-vertical in addition to sf-menu creates a vertical menu ***/
.sf-vertical, .sf-vertical li {
    width: 10em;
}
/* this lacks ul at the start of the selector, so the styles from the main CSS file override it where needed */
.sf-vertical li:hover ul,
.sf-vertical li.sfHover ul {
    left: 10em; /* match ul width */
    top: 0;
}