This is a dumb problem but I can't seem to set the padding on a submit button properly. No matter what I input for padding, the width and height of the button never changes. Here is the css:

.green_submit {
color: #fff;
background-color: #94c909;
border-right: 1px solid #6d9307;
border-bottom: 1px solid #6d9307;
border-left: none;
border-top: none;
padding: 25px;
}

And the HTML:

<input type="submit" class='green_submit' value="Validate" />

Any obvious problems here? How can I manipulate the padding on a submit button?