body {
          background-color:#edecec;
        }
        
        /* basic menu styles */
        .nav-menu {
          display: block;
         /* background: #74adaa;*/
          width:1200px;
          margin: 0px auto 30px;
        }
        .nav-menu > li {
          display: inline;
          float:left; 
		  margin:0px 10px;
          border-right:1px solid #94c0be;
        }
        .nav-menu > li:last-child {
          border-right: none;
        }
        .nav-menu li a {
          color: #fff;
          display: block;
          text-decoration: none;
          /*调用本地字体*/
          font-family:sansationregular;
          -webkit-font-smoothing: antialiased;
          -moz-font-smoothing: antialiased;
          font-smoothing: antialiased;
          text-transform: capitalize;
          overflow: visible;
          line-height: 20px;
          font-size: 20px;
          padding: 15px 30px 15px 31px;     
        }
        
        
        .three-d {
          /* 任务三、设置3D舞台布景 */
          -webkit-perspective: 200px;
          -moz-perspective: 200px;
          -ms-perspective: 200px;
          -o-perspective: 200px;
          perspective: 200px;
          /*任务四、设置3D舞台布景过渡效果*/
          -webkit-transition: all .07s linear;
          -moz-transition: all .07s linear;
          -ms-transition: all .07s linear;
          -o-transition: all .07s linear;
          transition:all .7s linear;
          position: relative;
        }
        
        .three-d:not(.active):hover {
          cursor: pointer;
        }
        
        /*任务五、给不是当前状态的3D舞台的悬浮与聚焦状态设置变形效果*/
        .three-d:not(.active):hover .three-d-box, 
        .three-d:not(.active):focus .three-d-box {
        -wekbit-transform: translateZ(-25px) rotateX(90deg);
        -moz-transform: translateZ(-25px) rotateX(90deg);
        -o-transform: translateZ(-25px) rotateX(90deg);
        -ms-transform: translateZ(-25px) rotateX(90deg);
        transform: translateZ(-25px) rotateX(90deg);
    /*    -webkit-transform:rotateX(90deg) translatez(-25px);*/
       /*   -webkit-transform:rotatex(90deg);*/
        }
        
        .three-d-box {
          /*任务六、给3D舞台中“.three-d-box”设置过渡与变形效果*/
          -webkit-transition: all .3s ease-out;
          -moz-transition: all .3s ease-out;
          -ms-transition: all .3s ease-out;
          -o-transition: all .3s ease-out;  
          transition: all .3s ease-out;
          -webkit-transform: translatez(-25px);
          -moz-transform: translatez(-25px);
          -ms-transform: translatez(-25px);
          -o-transform: translatez(-25px);
          transform: translatez(-25px);
          -webkit-transform-style: preserve-3d;
          -moz-transform-style: preserve-3d;
          -ms-transform-style: preserve-3d;
          -o-transform-style: preserve-3d;
          transform-style: preserve-3d;
          -webkit-pointer-events: none;
          -moz-pointer-events: none;
          -ms-pointer-events: none;
          -o-pointer-events: none;
          pointer-events: none;
          position: absolute;
          top: 0;
          left: 0;
          display: block;
          width: 100%;
          height: 100%;
        }
        
        /*任务七、给导航设置3D前，与3D后变形效果*/
        .front {
            -webkit-transform: rotatex(0deg) translatez(25px);
            -moz-transform: rotatex(0deg) translatez(25px);
            -ms-transform: rotatex(0deg) translatez(25px);
            -o-transform: rotatex(0deg) translatez(25px);
            transform: rotatex(0deg) translatez(25px);
         }
        
        .back {
          -webkit-transform: rotatex(-90deg) translatez(25px);
          -moz-transform: rotatex(-90deg) translatez(25px);
          -ms-transform: rotatex(-90deg) translatez(25px);
          -o-transform: rotatex(-90deg) translatez(25px);
          transform: rotatex(-90deg) translatez(25px);
          color: #FFE7C4; 
        }
        
        .front, .back {
/*          border:1px solid red;*/
          display: block;
          width: 100%;
          height: 100%;
          position: absolute;
          top: 0;
          left: 0;
          background: #74adaa;
          padding: 15px 30px 15px 31px; 
          color: white;
          -webkit-pointer-events: none;
          -moz-pointer-events: none;
          -ms-pointer-events: none;
          -o-pointer-events: none;
          pointer-events: none;
          -webkit-box-sizing: border-box;
          box-sizing: border-box;
        }
        /*任务八、设置导航当前状态与悬浮状态下的背景效果*/
        .nav-menu li .active .front,
        .nav-menu li .active .back,
        .nav-menu li a:hover .front,
        .nav-menu li a:hover .back {
             background-color: #51938f;
             -webkit-background-size: 5px 5px;
             background-size: 5px 5px;
             background-position: 0 0, 30px 30px;
             background-image: -webit-linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480), linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480);
             background-image: -moz-linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480), linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480);
             background-image: -ms-linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480), linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480);
             background-image: -o-linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480), linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480);
             background-image: linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480), linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480);
        }
        .nav-menu ul {
          position: absolute;
          text-align: left;
          line-height: 40px;
          font-size: 14px;
          width: 200px;
          -webkit-transition: all 0.3s ease-in;
          -moz-transition: all 0.3s ease-in;
          -ms-transition: all 0.3s ease-in;
          -o-transition: all 0.3s ease-in;
          transition: all 0.3s ease-in;
          -webkit-transform-origin: 0px 0px;
          -moz-transform-origin: 0px 0px;
          -ms-transform-origin: 0px 0px;
          -o-transform-origin: 0px 0px;
          transform-origin: 0px 0px;
          -webkit-transform: rotateX(-90deg);
          -moz-transform: rotateX(-90deg);
          -ms-transform: rotateX(-90deg);
          -o-transform: rotateX(-90deg);
          transform: rotateX(-90deg);
          -webkit-backface-visibility: hidden;
          -moz-backface-visibility: hidden;
          -ms-backface-visibility: hidden;
          -o-backface-visibility: hidden;
          backface-visibility: hidden;
        }
        /*任务九、显示下拉导航菜单，并其设置一个变形效果*/
        .nav-menu > li:hover ul {
/*          display: block;*/
           -webkit-transform: rotateX(0deg);
           -moz-transform: rotateX(0deg);
           -ms-transform: rotateX(0deg);
           -o-transform: rotateX(0deg);
           transform: rotateX(0deg);
         }