Responsive Tracks Without a Media Query
Let available width decide how many minimum-sized columns fit.
auto-fit
One
Two
Three
repeat(auto-fit, minmax(9rem, 1fr)) collapses empty tracks, so the existing items stretch into the available space.
auto-fill
One
Two
Three
auto-fill keeps space for empty tracks that fit. At narrower widths both examples wrap similarly; at wider widths the preserved tracks reveal the difference.