hi esmi, i found this in my theme.. i’m not sure if it is useful for your advice… ??
/*————————————————*/
/*—————[DEFAULT DROPDOWN SETTINGS]—*/
/*————————————————*/
.nav li ul { position:absolute; top:-999em; }
.nav li ul, .et_mobile_menu { z-index: 9999; width: 238px; background: #25383b; -webkit-box-shadow: 3px 3px 4px rgba(0,0,0,0.2); -moz-box-shadow: 3px 3px 4px rgba(0,0,0,0.2);box-shadow: 3px 3px 4px rgba(0,0,0,0.2); padding: 8px 0 8px; display: none; text-align: left; }
.nav li { position: relative; }
.nav ul li { float: none; }
.nav ul a { display:block !important; float: none !important; }
.nav li:hover ul, ul.nav li.sfHover ul { left: -19px; top: 28px; }
.nav li:hover li ul, .nav li.sfHover li ul, .nav li:hover ul, .nav li li:hover ul { top:-999em; }
.nav li li { padding: 0; height: auto !important; display: block !important; }
.nav li li ul { z-index: 1000; }
.nav li li a:link, .nav li li a:visited, .et_mobile_menu a { display: block !important; height: auto; padding: 9px 10px 9px 30px !important; }
.nav li:hover { visibility: inherit; /* fixes IE7 ‘sticky bug’ */ }
.nav li li:hover ul, ul.nav li li.sfHover ul { left: 238px; top: -10px; }