input text width not 100% responsive on all devices

I've fonud this StackOverFlow questions and it seemed to make sense for my situation: Input text box and width 100%

I'm simply trying to make an input type="text" form (where a user types in information) 100% wide on all devices/dimensions (240, 320, 480, 768, 1024).

My HTML is:

<div align="left">
            <table>
              <tr>
                <td>First Name:</td>
                <td>input type="text" name="first_name" style="width: 100%;" />
                </td>
              </tr>
            </table>

My CSS:

input { width: 100%; }

I can't seem to get the input text area 100% wide??? On an iphone (320) its too wide and makes you scroll left/right. Any suggestions? Thank You!

Regards,