Technique : C27 and GDPR compliant cookie banner

Hello,

The GDPR obliges to collect the consent of users for the processing of
their personal data. A banner is therefore added and very often it is
positioned sticky at the bottom of the page. However the banner should be
positioned in the code at the beginning of the DOM. If I understand well
the C27 technique <https://www.w3.org/WAI/WCAG21/Techniques/css/C27> in the
case where the banner is positioned at the top of the DOM, should it also
be positioned visually at the top of the page?

Sincerely

--
Steven