Width height issue for email and textarea

There is a difference in the size of an email field and textarea when compared to the text fields.

email
– the height of the email field is less then text fields
– the width is less then text fields, although both are set to 103/

textarea
– the width is wider then a text field although it is set 103x

You can see it at http://www.bouwjewebsitezelf.nl/contact/
The settings are:

Je naam (verplicht)
[text* your-name 103/]
Je emailadres (verplicht)
[email* your-email 103/]
Onderwerp (verplicht)
[text* your-subject 103/]
Je bericht (verplicht)
[textarea* your-message 103x]

Why are the width/height sizes different and how can I fix this?

Thank you!
John-Pierre

http://wordpress.org/extend/plugins/contact-form-7/