Surbma – Divi & Gravity Forms – This plugin adds the same styling for Gravity Forms as Divi Theme has for its own forms. This is a very lightweight plugin with minified css to reduce the loading time as low as possible.
It also adds responsive styles to Gravity Forms. So you can use complex forms, halves or thirds fields, your form will look great on mobile screens also.
Surbma – Divi & Gravity Forms is FREE!!