reproduce:
Read any article with very large table content (for example see https://en.wikipedia.org/wiki/Usage_share_of_web_browsers ). Scroll attempting to correlate row content with a specific column meaning. Note how header scrolls out of view while rows are visible and lose context on large tables.
solution:
Make headers of tables "sticky" when scrolling such that they remain visible in the viewport until the entire table scrolls out of bounds.
This CSS applies this too broadly and perhaps needs a "main" or similar content-area specific selector added.
thead th {
position: sticky;
top: 0;
/* future logical positioning as ignorable overrides */
inset-block: 0 auto;
inset-inline: unset unset;
}