500234 (3) [Avatar] Offline
#1
At this place in book - https://livebook.manning.com/#!/book/css-in-depth/chapter-4/v-9/165

You applied padding to columns. I was wondering why didn't you use margin to columns as margin's job is to separate two blocks and padding separate content and border.

I'm curious to know why padding instead of margin.
Keith J Grant (36) [Avatar] Offline
#2
In this particular case, either padding or margin on the `column` should work, because the we are more concerned with spacing the `media` within it, not the column itself. I used padding in this case because that is what Bootstrap 3 does: I wanted a reader to be able to examine a Bootstrap-based page after reading this chapter and understand how it works, and how they could implement the same thing without Bootstrap.