a.css-3d-btn{ 
 position: relative; 
 color: rgba(255, 255, 255, 1); 
 text-decoration: none; 
 background-color: rgba(219, 87, 51, 1); 
 font-family: "Microsoft YaHei", 微軟雅黑, 宋體; 
 font-weight: 700; 
 font-size: 3em; 
 display: block; 
 padding: 4px; 
 border-radius: 8px; 
 /* let’s use box shadows to make the button look more 3-dimensional */ 
 box-shadow: 0px 9px 0px rgba(219, 31, 5, 1), 0px 9px 25px rgba(0, 0, 0, .7); 
 margin: 100px auto; 
 width: 160px; 
 text-align: center; 
 -webkit-transition: all .1s ease; 
 -moz-transition: all .1s ease; 
 transition: all .1s ease; 
} 

/* now if we make the box shadows smaller when the button 
is clicked, it’ll look like the button has been "pushed" */ 

a.css-3d-btn:active{ 
 box-shadow: 0px 3px 0px rgba(219, 31, 5, 1), 0px 3px 6px rgba(0, 0, 0, .9); 
 position: relative; 
 top: 6px; 
}