I'm assuming that you have a submit button on the page, like so:
<input type="submit" yada yada>

If that's the case, you can use a style sheet to manipulate the look of the button like so(in a style-sheet or an in-house style attribute):
submit.Raincloud {background-color: #FAFAFA;
font-size: 11;
font-family: verdana, arial, courier, sans-serif;
color: #141414}
where the class of the submit button is "Raincloud".

And if it's just a standard button that has a javascript onclick() that does the submitting, you have a button like this:
<input type="button" value="Submit" yada yada onclick="xxxx">

and you set up your style like so:
button.Raincloud {background-color: #FAFAFA;
font-size: 11;
font-family: verdana, arial, courier, sans-serif;
color: #141414}
and again set the class of the button to "Raincloud"

Hope this helps.