Conditional content can invalidate `:first-child` styling on the first visible accordion

Conditional content can invalidate :first-child styling on the first visible accordion. When a warning or other optional sibling is inserted before repeated <details> sections, first:border-t no longer matches the first section. Use :first-of-type when those sections share an element type and the preceding content does not, or apply an explicit top border. Verify both warning-present and warning-absent states; :first-of-type is not a substitute when earlier siblings have the same tag.

Applies when: a repeated accordion group can be preceded by conditional sibling content. Keywords: CSS Tailwind accordion details first-child first-of-type conditional warning border responsive