Input buttons rendering different in Firefox than in IE/Chrome

[Eiolon]

I have submit buttons and they look identical in IE and Chrome but are rendering differently in Firefox.  It looks like they are adding padding to it, even though I have a CSS reset and explicitly state the padding.

 

Any ideas on how to force it to look like the IE/Chrome variants?

 

It typically isn't a problem but when the button is next to a text field it isn't uniform with it like the other browsers.

 

.button_submit { 
margin:0; 
padding:6px 12px 6px 12px; 
display:inline-block; 
border:solid 1px rgba(0,0,0,.05); 
border-radius:2px; 
font-family:Arial, Helvetica, sans-serif; 
font-size:13px;
color:#FFFFFF; 
text-align:center; 
text-decoration:none; 
vertical-align:baseline;
cursor:pointer;
}