How to set Width Search Input Box

1. catalog\view\theme\default\template\common\header.tpl

find this code:
<input type="text" value="<?php echo $text_keyword; ?>" id="filter_keyword" onclick="this.value = '';" onkeydown="this.style.color = '#000000'" style="color: #999;">

Replace width:
<input type="text" value="Search Keywords" id="filter_keyword" onclick="this.value = '';" onkeydown="this.style.color = '000000'" style="color: #999;width:154px;">

2. Save & Refresh

how to