It is your theme but it’s pretty simple to fix if you have even a little HTML & CSS skills – see http://contactform7.com/faq/#Why_does_my_email_address_input_field_look_different which gives some guidance on how make these fields look the same in your current WordPress theme.
CF7 now uses the new HTML5 input[type=”email”] for email fields and input[type=”text”] for other fields. Looks like the CSS in your current WordPress theme does not cater for this new HTML5 email input field.
See also Styling Contact Form for a general explanation of styling CF7 forms using CSS. If you are not familiar with CSS, this page also includes some links to where you can learn CSS.
If you find this too challenging you could consider contacting your Theme provider about this issue. It’s a very basic issue that most of the better themes have now addressed.
