[Typo3] How to customize a "search" form?

[Martin Wan]

Hi all,

As I listed in subject, my website needs to provide searching function.
Following is the layout:
        _____________________
Search |                     |
       -----------------------

The layout is not like the default one, in which the input text field is at
left and the "search" button at right. How to change the search content
layout? 

Also, I need to change the CSS style of the "search" button, How to
implement? Could you please give some hints? Thanks in advance.

Martin Wan