How can i modify the height of input textfield in login form in drupal 7? how can i costumize a form ( for example login form ) in /user and specifically the height of input textfield? And the button "login"?
I try with the function theme_form_element() but nothing good!
The easiest way to do this, is with CSS

An example could be:

.form-submit {
  height: 30px;
 }


You can't set height on textfields and submit buttons AFAIK, only text areas.