Have you submitted a form and it redirected to form builder url and displayed without styles? If so, here is the solution
- Make sure to add these scripts to MVC OuterLayout.cshtml and reference it in MVCLayout.cshtml. More details, refer the documentation (Steps 3 and 4)
@using Sitecore.ExperienceForms.Mvc.Html @Html.RenderFormStyles() @Html.RenderFormScripts()
Any questions, please leave a comment. Happy sitecoring!