Create Date Badge with Wordpress and CSS

css

body { font-size: 62.5%; }
.post { 
    position: relative;
    margin-left: 4.8em;
}
.entryDate { 
    border: 1px solid #999; 
    font-family: Georgia,"Times New Roman", serif; 
    left: -4.8em; 
    line-height: 1; 
    position: absolute; 
    top: 0; 
    width: 3.5em;
}
.entryDate span { 
    display: block; 
    text-align: center; 
}
.postMonth { 
    text-transform: uppercase; 
    font-size: 1.2em;
    padding-top: 0.3em; 
}
.postDay { font-size: 2em; }
.postYear { 
    background-color: #2358B8; 
    color: #FFF; 
    font-size: 1.2em; 
    padding: 0.3em 0; 
    margin-top: 0.3em;
}

html

<div class="entryDate">
   <span class="postMonth"><?php the_time('M') ?></span>
   <span class="postDay"><?php the_time('d') ?></span>
   <span class="postYear"><?php the_time('Y') ?></span>
</div>