Steps to reproduce the issue

Look at a page using back to top on the w3c validator. You can view my test site: Test Site VVFH
W3C Validation

I'm using the Cassiopeia template. The back to the top button is selected in the Advanced tab of the Template Style.

Expected result

Passes w3c validation

Actual result

Error: Element style not allowed as child of element body in this context. (Suppressing further errors from this subtree.)
From line 171, column 5; to line 171, column 11
↩ ↩ <style>↩ .jj-
Contexts in which element style may be used:
Where metadata content is expected.
In a noscript element that is a child of a head element.
Content model for element body:
Flow content.

System information (as much as possible)

LAMP system running Joomla 4.2.2 (upgraded from 3.10.11) with php 8.0.22, LiteSpeed V8.0.1 Cloudlinux 1.3, and mariadb 10.3.35

Additional comments

I tested surrounding the social slider code with a div, but that did not clear the error.