Minard demo too narrow without .page-columns.page-full all the way up

[jimjam-slam]

I picked up a problem with the Minard scroll while recording our videos — it seems that in issue #81 (PR #82), we do indeed need to propagate .page-columns.page-full all the way up to main. Minard is a case where we don't (only on the direct parent section), and it causes the full grid to "sandwich" into the page column.

I think I can probably revert that to going all the way up today and put out a quick bug fix release 1.0.1 if that's okay with you, @andrewpbray!

[jimjam-slam]

I think we just need to revert c9c6a9b for this.

[jimjam-slam]

I'm not sure who pointed this AI at our repo... #122 does not solve the issue at hand, and it edits our generated CSS, not the source SCSS file.

it did, however, pick up a separate issue in our .sidebar-right layout! I'll fold that into #123 (which is my PR).

[jimjam-slam]

Fixed in #123!