Expected: column 1 is 100px (orange), column 2 is 25% of 600px = 150px (green), columns 3 and 4 share the rest. Second table: the explicit width sits on a second-row cell (purple, 320px) — it must still win the column width (320px is deliberately not the equal share, so a failure is visible).
| 100px | 25% | auto | auto |
| x | x | x | x |
| auto | auto | auto |
| 320px on row 2 | x | x |