A responsive specification describes relationships between boxes, not one screenshot. On a wide screen, three workload sections should share a row with equal widths and a measured gap. On a phone, the same source order should become a vertical stack. Long content still has to fit, so minimum sizes and text wrapping are part of the layout contract.
You'll build one grid and inspect it at two explicit preview widths. Use flexible tracks with a zero minimum so a long label cannot force the whole page wider. Keep controls inside their section and let text wrap. The checks compare element boxes and page overflow rather than a CSS class name alone. A different implementation is valid when it produces the same relationships at both required widths.