Input field width and height: how to change them

I've never touched drupal's theming layer before, so I apologize for the basic question. I'm trying to change the default width and height for the input fields used in drupal forms.

Is there a generic template that I need to change? or do I have to find everywhe开发者_Go百科re where there's a form, find its template, and change it. Any tips on how to proceed with this?

If you want to change all inputs' width you can use pure css. All inputs in drupal have a class called "form-text".

So you can write

.form-text{
    width:100px;
}

If you really want to wirte your own template - you should look towards the theme_form_element function.