Centering main menu

I have been trying to center my main menu at the top of the page using the CSS below and variations of it, but nothing has been centering it!!

#nav { text-align:center; }
#nav li { text-align:left; }
#nav > li { text-align: center }
float: none !important;
display: inline-block !important; }
centercar {align:center;}
.my-list {list-style-type: disc!important;list-style-position: inside;}