The most commonly reported issue was caused by a default 45% blanket width value applied to all inputs in the content area..

.format_text input, #commentform input, #commentform textarea {
	border-width:0.071em;
	padding:0.214em;
	width:45%;
}

This affected radio and checkbox inputs as well and resulted in labels aligning incorrectly, wrapping, etc. Also, a default border value for the inputs (including buttons) was being applied, even if you chose to use an image for the submit button.

• Thesis screenshot without new styles
• Thesis screenshot with new Gravity Forms styles added

Of course, if you're using a heavily customized version of the Thesis theme, as with any others, there may be other inheritance issues.

We've defined a base set of generic styles for the forms that should work well with most themes and have also tried to keep them flexible enough they can inherit properties from the theme so they don't have to be completely restyled.

What you see when you preview the form in the form admin is simply the default styles with no influence from the theme or other external sources. The preview isn't intended to be indicative of the final styling in the theme, simply a way to preview the working form.

If you want Thesis forms to look like the preview forms, you'll have to use some custom CSS to override the defaults in the thesis layout styles.

That said, if you simply disable the default Gravity Forms CSS, you may run into issues where elements are unstyled (datepicker, etc.) - unless everything is accounted for in your theme CSS.

If you want to heavily modify the styles, our recommendation is to disable the CSS output in the form settings, copy the entire contents of the forms.css file from the plugin directory, and append that to your custom.css (for thesis) or theme style sheet whatever it may be called (usually style.css). You can then modify the default styles to your preferences and the styles won't be overwritten when you update the plugin.