Form input text box way too big

I had another thread open but it was marked closed.
The form text input boxes are too large in my opinion.

I was sent this code to insert into the Quick CSS box, but nothing changed:

#top .main_color .input-text, #top .main_color input[type='text'], #top .main_color input[type='input'], #top .main_color input[type='password'], #top .main_color input[type='email'], #top .main_color input[type='number'], #top .main_color input[type='url'], #top .main_color input[type='tel'], #top .main_color input[type='search'], #top .main_color textarea, #top .main_color select {
    padding: 5px;
}
.form_element_half input {
    width: 90%!important;
}

Can someone please help me find how to change the padding/height of the text input box. text area, etc?

Thanks! :-)