You mean two classes? “Chain” the selectors (no spaces between them):
.class1.class2 {
/* style here */
}
This selects all elements with class1
that also have class2
.
In your case:
li.left.ui-class-selector {
}
Official documentation : CSS2 class selectors.
As akamike points out a problem with this method in Internet Explorer 6 you might want to read this: Use double classes in IE6 CSS?