In the first two chapters of this book, we established a framework of relying on external CSS stylesheet files to provide formatting for HTML elements (such as headings, paragraphs, and links) and special ID and class styles that can be applied to the
div tags to design pages.
How does that doctrine apply to customizing form input? The short answer is: You create styles for the different form elements. The long answer: Well, we'll walk through how to do that now.
The following are the key HTML elements to which CSS styles can be applied to customize form appearance:
<form>element style defines the appearance of the entire form.
<input>element style defines the appearance of input fields (such as text fields).