Caldera Forms is designed to look great with most any WordPress theme. You may need to add some additional style to match your site. Caldera Forms is designed to be very easy to apply custom CSS to.
Don’t Want To Write CSS?
Caldera Forms Style Customizer for Divi & Extra gives you total control over the look of your forms — all from the customizer, no CSS required.
Where To Put Custom Styles For Caldera Forms