CSS3自适配手机屏幕

       @media only screen and (max-width:350px){
          .img{
             width: 80px;
             height:70px;
             background-image: url(./images/heart2.png);
             background-size: % %;
             float: left;
             margin-top: %;
             margin-left: %;
             font-size: 10px;
        }
      }
       @media only screen and (min-width:350px){
      .img{
             width: 100px;
             height: 85px;
             background-image: url(./images/heart2.png);
             background-size: % %;
             float: left;
             margin-top: %;
             margin-left: %;
             font-size: 10px;
        }
      }

根据屏幕大小（长宽）来调整css样式，达到手机屏幕适配的效果。