CSS not being applied to AJAX content

Hi, when a visitor views the initial page the CSS styling is correct. When they navigate to the next page (load data) using AJAX the correct CSS styling is not applied. However, if I load the page manually (without AJAX), the CSS then works again as it should. I understand the concept of there only being data loaded by AJAX but there must be a way to apply the stylesheets that are already loaded within the header? Can someone please advise if they know how to achieve this as I have searched for months now for this solution.
Thanks.