Someone good at CSS help, my website design is dying

A developer encounters a subtle CSS rendering issue when trying to add rounded top corners and a border to card-style article elements. The first attempt at applying border-radius to the article element does nothing because child elements overflow their container. Adding border-radius to the header fixes the visual rounding but introduces a white fringe artifact at the border junction. The root cause is anti-aliasing: clipping two overlapping semi-transparent surfaces separately before compositing them causes white to bleed in at the edges. Using overflow: auto on the article element is the more correct approach but still doesn't fully eliminate the artifact, leaving the problem unresolved.