Text selection impossible on top of titles

All the `h1`, `h2` and `h3` have a positive `padding-top` and a negative `margin-top` like:

https://github.com/gridsome/gridsome.org/blob/f563027d4a8bc07c96ae023ba62a933c687d60b7/src/assets/style/docs.scss#L21-L23

Because of this negative `margin-top` the text above any title can't be selected _(in the green area)_:


----

## Solution

Can't we just do something like:

```css
h1, h2, h3 {
margin-top: 6rem;
}
```

If yes, I'm happy to open a PR.
Otherwise I'm curious about the usage of a negative margin/positive padding in this case?