Contact Form Needed

My client needs a contact form to include...

Subject line, their name, company name, mailing address, email address, phone #, and Message

From what I read wpmu contact form plugin is limited in this respect but I stand corrected.

I know that many people use WP Contact Form 7 (I think it's called) but the issue seem to be it's not Responsive unless you style it.

Do you have any css suggestions I can use for this purpose and where do I add the css?

It's for the dcspecialevents.net website

Thanks