一款纯css3实现的动画按钮

<div class="black">
            <a href="#" class="btn"><span>Become A Member</span> <i>&rarr;</i> </a><a href="#"
                class="btn"><span>Support Us</span> <i>&rarr;</i> </a><a href="#" class="btn"><span>
                    Going Down</span> <i class="down">&rarr;</i> </a><a href="#" class="btn"><span>Sign
                        Up</span> <i class="up">&rarr;</i> </a>
        </div>
        <div class="white">

            <a href="#" class="btn"><span>Become A Member</span> <i>&rarr;</i> </a><a href="#"
                class="btn"><span>Support Us</span> <i>&rarr;</i> </a><a href="#" class="btn"><span>
                    Going Down</span> <i class="down">&rarr;</i> </a><a href="#" class="btn"><span>Sign
                        Up</span> <i class="up">&rarr;</i> </a>
        </div>

   body
        {
        }
        
        h1
        {
            font-family: "Abril Titling" , Georgia, serif;
            color: #f9f9f9;
            letter-spacing: 1px;
        }
        
        body div
        {
            padding: 60px 0;
            text-align: center;
            height: 80px;
            margin-top: 0;
        }
        
        .black
        {
            background: #262D28;
        }
        
        .white
        {
            background: #f9f9f9;
        }
        
        a
        {
            display: inline-block;
            margin: 10px;
        }
        
        .btn
        {
            position: relative;
            width: 160px;
            padding: 1.2rem 3rem;
            border: 1px solid #0AA944;
            font-size: 15px;
            text-decoration: none;
            color: #f9f9f9;
            font-family: "Tablet Gothic" , sans-serif;
            text-transform: uppercase;
            font-weight: 300;
            letter-spacing: 1.5px;
            -webkit-transition: all .2s ease-out;
            -moz-transition: all .2s ease-out;
            -ms-transition: all .2s ease-out;
            -o-transition: all .2s ease-out;
            transition: all .2s ease-out;
        }
        
        .white .btn
        {
            color: #262D28;
            border: 2px solid #0AA944;
        }
        
        .btn span
        {
            position: relative;
            top: 2px;
            left: 0;
            -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;
        }
        
        .btn i
        {
            opacity: 0;
            position: absolute;
            margin-top: -21px;
            top: 2.5rem;
            left: 120%;
            -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;
        }
        
        .btn:hover
        {
            background: rgba(255,255,255, .9);
            border: 1px solid rgba(0,0,0,1);
        }
        
        .white .btn:hover
        {
            background: rgba(0,0,0, .02);
            border: 2px solid rgba(0,0,0,1);
        }
        
        .btn:hover span
        {
            color: #333;
            left: -20px;
        }
        
        a.btn:hover i
        {
            opacity: 1;
            left: 80%;
            color: #333;
            -webkit-transform: scale(1.2);
        }
        
        a.btn:hover .up
        {
            -webkit-transform: rotate(270deg);
        }
        
        a.btn:hover .down
        {
            -webkit-transform: rotate(90deg);
        }