DIV+CSS教程_解决display:table-cell带来的莫名空白(irefox)

display:table-cell带来的莫名空白（firefox）?

在firefox下，
我把.main设置为display:table-cell;如果在.main内部添加浮动div，就会在该div下方莫名多出一些空白，请问怎么解决？
前提是.main必须设置为display:table-cell;
代码: <style type="text/css">
.main{display:table-cell;*display:block;width:auto;}
.body,.main{*zoom:1;}
.body:after,.main:after{clear:both;display:block;visibility:hidden;overflow:hidden;height:0 !important;line-height:0;font-size:xx-large;content:" x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x ";}
.line:after,.lastUnit:after{content: " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ";visibility:hidden; clear:both;height:0 !important;display:block;line-height:0;font-size: xx-large;overflow: hidden;}
.line{*zoom:1;}
.fl{float:left;}
.main{background-color:tan}
.main div{background-color:lightblue}
</style>
<div class="line">
    <div class="main">
        <div>good</div>
    </div>
</div>
<br/>
<br/>
<br/>
<div class="line">
    <div class="main">
        <div class="fl">good</div>
    </div>
</div>

解决 设置填充就好了