复合的使用

/*标签名查找*/
            span
            {
                color: orange;
            }
            /*id查找*/
            #aa
            {
                 100px;
                height: 100px;
                background-color: red;
            }
            /*class查找*/
            .bb
            {
                 100px;
                height: 100px;
                background-color: red;
            }
            /*并列*/
            .cc,#dd
            {
                 100px;
                height: 100px;
                background-color: red;
            }
            /*父代*/
            #wai #li
            {
                 100px;
                height: 100px;
                background-color: red;
            }
            /*父代,并列*/
            #wai #li,.limian
            {
                 100px;
                height: 100px;
                background-color: red;
            }