CSS中实现两个DIV左右并排摆放

Css中实现两个DIV左右并排摆放，且自动按比例伸缩

#Div0

        {

          float:left; background-color:Blue; width:100%; height:180px;

        }

        #Div1

        {

          float:left; background-color:Blue; width:70%; height:180px;

        }

        #Div2

        {

           background-color: Green; width:30%;height:180px; float:right;

        }