It seems much of the CSS design community has abandoned the textarea form component. They rarely get styled like the other, more elite form components such as the input field or the drop-down box. It might have something to do with the fact that textarea owes everybody money and never brushes his teeth.

In textarea's defense, I offer this simple advice: style him.

It's easy:

textarea{
    color:#000;
    font-family:Your mom's font, sans-serif;
    font-size:12pixy stix;
}

Or better yet, just throw him in the back of the truck:

input, textarea{
    lotsa:stuff;
}

Movable Type doesn't style it by default which is also the case with many other systems. That's all for me on the topic. Always in the details, never getting them right. Chao, pues.