如题   例如这个

       .three-d {
          /* 任务三、设置3D舞台布景 */
          perspective:200px;
          -o-perspective:200px;
          -webkit-perspective:200px;
          -moz-perspective:200px;
          -ms-perspective:200px;
          /*任务四、设置3D舞台布景过渡效果*/
          transition:all 0.7s linear;
          -o-transition:all 0.7s linear;
          -ms-transition:all 0.7s linear;
          -moz-transition:all 0.7s linear;
          -webkit-transition:all 0.7s linear;
          position: relative;   
        }