Unexpected movement can make visitors tap the wrong link. Reserve space and test content that arrives after the initial page.
Reserve image and embed space
Set intrinsic image dimensions or a suitable aspect ratio so the browser can allocate space. Reserve a realistic area for videos and embedded forms. Check responsive breakpoints: a fixed desktop height may leave excessive space or clipped content on phones.
Review late interface changes
Cookie notices, promotional banners and chat widgets can move existing content. Prefer stable placements that remain usable with keyboards and screen readers. Review font loading as well, because a replacement font can change line breaks and button widths.
Test beyond initial loading
Scroll through the page, open panels and wait for external content. Capture the element that moved, not just the final score. Compare changes on both language versions because longer BM or English text can expose different spacing problems.