除了标签的高度外，一切正常，如下图所示：
我只改变了颜色，教程中的代码是一样的！
提前谢谢大家！
编辑：
HTML：
<a href="javascript:void(0);">Avanti</a>
CSS：
a {
position: relative;
color: rgba(255,255,255,1);
text-decoration: none;
background-color: rgba(0,76,126,1);
font-family: 'Oswald';
font-weight: 700;
font-size: 2em;
display: block;
padding: 4px;
-webkit-border-radius: 8px;
-moz-border-radius: 8px;
border-radius: 8px;
-webkit-box-shadow: 0px 9px 0px rgba(0,34,56,1), 0px 9px 25px rgba(0,0,0,.7);
-moz-box-shadow: 0px 9px 0px rgba(0,34,56,1), 0px 9px 25px rgba(0,0,0,.7);
box-shadow: 0px 9px 0px rgba(0,34,56,1), 0px 9px 25px rgba(0,0,0,.7);
margin: 25px auto;
width: 160px;
text-align: center;
-webkit-transition: all .1s ease;
-moz-transition: all .1s ease;
-ms-transition: all .1s ease;
-o-transition: all .1s ease;
transition: all .1s ease;
}
a:active {
-webkit-box-shadow: 0px 3px 0px rgba(0,34,56,1), 0px 3px 6px rgba(0,0,0,.9);
-moz-box-shadow: 0px 3px 0px rgba(0,34,56,1), 0px 3px 6px rgba(0,0,0,.9);
box-shadow: 0px 3px 0px rgba(0,34,56,1), 0px 3px 6px rgba(0,0,0,.9);
position: relative;
top: 6px;
}