I just looked at the website you sent me a link of via email.
because of this custom css you use, the transition doesn't work:
If you have custom links that should fade the website, please update lay theme to 2.8.7. Your links should resemble this format:
<a href="http://mywebsite.com/mypage" data-type="project" data-id="12" data-catid="[1,2]" data-title="My Title">My Link</a>
data-catid is optional, data-type can be "project", "page" or "category".
The id is the id of a page, catid are the ids of a project's category in case you link to a project. The title is the project's/page's title.