Why the margin-left fails in the two different resolutions in the above picture
淡淡烟草味2017-06-13 09:25:36
That’s not invalid, that’s overwritten. Look at the above img:nth-child(3)
伊谢尔伦2017-06-13 09:25:36
is covered because you wrote the @media query
@media can set different styles for different screen sizes
In the second picture, the effective margin-left:40 