resize the search sidebox

I try all day, but cannot find where to enlarge the size of search box and enlarge the size of "Enter Search..."
Please help :yes:

You might try this:

includes/ templates/ template_default/ sideboxes/ tpl_search.php
1. line 17
2. width= 100 to 135
3. line 19
4. width = 100 to 135
5. ftp to: includes/ templates/ your_template/ sideboxes/ tpl_search.php

Dear Sir,Thanks for respond, I try to change the size to 135px, but the search box still not change.
I reinstall a new website, it work partially, the search in upper one (sideboxes/search_header.php ) does not change and the lower one (sideboxes/search.php) is changed. how should I change to make the search_header.php change, please see the photo

Thanks I find the right way to enlarge the search size. it is "C:\xampp\htdocs\zen\includes\templates\template_default\sideboxes\tpl_search_header.php
the tpl_search.php is for side box ,what I need is search_header:hug:

Ty for posting the right fix ...