Responsive 3-column preview card component solution - Flexbox

I know I am not meant to 'chase for the pixel-perfect dream', but I am sure the mobile version of the solution has less white space than the desktop version, is that right?

And is there anything I should think about in regards to using media queries? because I don't like using them because it feels like I am using it because I can't come up with a better solution to make something responsive '___'

Thank you!