janat08:
The column part of the guide uses floats, when columns are
supported since 2 years ago.
I’m assuming you are talking about CSS multi-column layout? You
are right that this is supported well now, but it is not that
useful for true multi-column layouts - such uses are better served
by Flexbox, or floats if older browser support is needed.
Multi-column layout is useful for displaying single bodies of
text in multiple columns, like a newspaper layout for example, but
it doesn’t work for multiple columns currently - it is very hard to
control where the columns break.