This seems like a good example of what the OP is preaching:

Learn the box model[0], and you won't have to 'fiddle' anymore, you'll know why your elements are arranged the way they are.

Or, you could keep ploughing through permutations of bootstrap magic until you stumble at the correct implementation.

[0]: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Box_Mod...