[SOLVED] Problem with Submit Button: Hover Style

Hi,

Using Wordpress 321 and Atrahualpa 367 - ata-round

My work-in-progress Web site is here:
http://julesgobeil.com/wpfr/

In Style Forms / Submit Buttons Default and Hover, I can configure the Submit Button: Default Style easily and it works fine. However, no matter what I do, I can't configure the Hover Style - it stays similar to the Default Style.

I have tried to add this in Add HTML/CSS Inserts / CSS Inserts:

.button:hover {
border: 1px solid #000;
background: #99CCFF;
}

and it doesn't work either.

Any idea why it doesn't work ?

Thanks for your help
Jules