If you’re looking to build responsive Contact Form 7 with a rich grid-layout (multiple-column layout) I would recommend you look at the Smart Grid-Lyout Extension for Contact form 7 plugin.
It has a UI editor that allows you to design a grid layout for your form fields.
In addition, it has the ability to turn dropdown fields into beautiful jquery select2 fields which are much more mobile-friendly as they don’t need to scroll down long lists to select an option. Simply built your dropdown tag with the additional select2 class to convert them,
[select* how-did-you-hear-about-us id:hear-about-us class:select2 first_as_label "Select your option" "Search Engine" "Direct Mail" "Auction" "Referral" "Other:"]