@import url("http://www.w3cplus.com/demo/css3/base.css");

@font-face {
    font-family: 'sansationregular';
    src: url('http://www.w3cplus.com/demo/css3/3DAnimationDropdownMenu/sansation_regular-webfont.eot');
    src: url('http://www.w3cplus.com/demo/css3/3DAnimationDropdownMenu/sansation_regular-webfont.eot?#iefix') format('http://www.w3cplus.com/demo/css3/3DAnimationDropdownMenu/embedded-opentype'),
         url('http://www.w3cplus.com/demo/css3/3DAnimationDropdownMenu/sansation_regular-webfont.woff') format('woff'),
         url('http://www.w3cplus.com/demo/css3/3DAnimationDropdownMenu/sansation_regular-webfont.ttf') format('truetype'),
         url('http://www.w3cplus.com/demo/css3/3DAnimationDropdownMenu/sansation_regular-webfont.svg#sansationregular') format('svg');
    font-weight: normal;
    font-style: normal;
}
body {
    background-color:#edecec;
}

/* basic menu styles */
.nav-menu {
  display: block;
    background: #74adaa;
    width:950px;
    margin: 50px auto 150px;
}
.nav-menu > li {
  display: inline;
  float:left;            
    border-right:1px solid #94c0be;
}
.nav-menu > li:last-child {
  border-right: none;
}
.nav-menu li a {
  color: #fff;
    display: block;
    text-decoration: none;
    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;            
}

/* animation domination */
.three-d {
  -webkit-perspective: 200px;
  -moz-perspective: 200px;
  -ms-perspective: 200px;
  -o-perspective: 200px;
  perspective: 200px;
  -webkit-transition: all .07s linear;
  -moz-transition: all .07s linear;
  -ms-transition: all .07s linear;
  -o-transition: all .07s linear;
  transition: all .07s linear;
  position: relative;
}

.three-d:not(.active):hover {
  cursor: pointer;
}

.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);
}

.three-d-box {
  -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%;
}

.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 {
  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;
}
.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;
}
.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);
}

你可以整体看一下