backdrop-filter (backdrop-blur-md, applied to the sticky header once
scrolled) creates a new containing block for position:fixed descendants,
same as transform does. NewsletterModal was rendered inside that header,
so its `fixed inset-0` backdrop silently stopped being fixed to the
viewport once scrolled and became fixed to the 100px header instead,
clipping the modal to the top of the page. Moved the modal to be a
sibling of <header> instead of a child.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Marco
f5df384b13