Html – Making emboss buttons

height: 160px;
width: 160px;
text-decoration: none;
text-transform: capitalize;

-webkit-border-radius: 20px;
-moz-border-radius: 20px;
border-radius: 20px;

border-width: 0px;
border-radius: 20px;

box-shadow: inset 0px -2px 1px rgba(0,0,0,0.8),
inset 0 2px 1px rgba(255,255,255,1);

margin: 15px 5px;

background: linear-gradient(top, #23b224, #23b224);
background: -webkit-linear-gradient(top, #23b224, #23b224);
background: -moz-linear-gradient(top, #23b224, #23b224);
background-image:-webkit-gradient(linear, 50% 0%, 50% 100%, color-stop(0%, #23b224), color-stop(100%, #23b224));  

The code above will produce the following result:

But what I want to achieve is something like this:

I want my buttons to appear like the buttons in the second picture. How to do it?