This is typically due to the way your CSS or jQuery/javascript is referencing an ID tag and/or hierarchy. In order to provide such advanced features on the fly, with no coding, we leverage the .Net server side to render the page. Therefore you will find a <form></form> wrapping your code as well as the <body> tag being empty.
To overcome these issues, you can:
Leverage jQuery to add a CSS class to the <body> tag via $(body).addClass('classname');
Update your CSS to ensure the hierarchy matches the DOM objects on the page.