how to stop this irritating css behaviour

Question

Here is a jsfiddle link: http://jsfiddle.net/qrzwD/

i just dont like my second li to move upward after the animation completes.

can someone help me to stop this.

here is my html:

 <nav>
    <ul>
        <li> <a class="content-box-blue" href="#"> </a> </li>
        <li> <a class="content-box-gray" href="#"> </a> </li>
    </ul>
</nav>

here is my css:

* {
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
box-sizing: border-box;
}
a {
text-decoration: none;
margin: 0;
padding: 0;
}
ul, li, nav {
margin: 0;
padding: 0;
}
nav {
float: right;
width: 400px;
margin-top: 35px;
margin-right: 10px;
}
nav ul {
list-style-type: none;
float: right;
}
nav li {
float: right;
clear: right;
margin-bottom: 20px;
}
.content-box-blue {
background-color: #00bfff;
border: 1px solid #afcde3;
height: 50px;
width: 0px;
border-top-left-radius: 8% 50%;
border-bottom-left-radius: 8% 50%;
text-align:center;
line-height:50px;
 }
 .content-box-gray {
background-color: #FF69B4;
border: 1px solid #bdbdbd;
height: 50px;
width: 0px;
border-top-left-radius: 12% 50%;
border-bottom-left-radius: 12% 50%;
text-align:center;
line-height:50px;
 }

here is my jquery code:

$(function(){
    $(".content-box-blue").animate({width:'350px'},1200,function(){$('<span>Charcoal Paintings</span>').fadeIn(1000).appendTo($(this));});

    $(".content-box-gray").animate({width:'250px'},1200,function(){$('<span>Sketches</span>').fadeIn(2000).appendTo($(this));});

});

Answer 1

Set the height on LI instead of A:

li {height:50px;}

http://jsfiddle.net/qrzwD/3/

The newly appended A is making the LI change the overall height

Answer 2

It can be solved by setting display:block for both .content-box-blue and .content-box-gray

fiddle here