Appearance → Customize → Layout. Under the two sliders, three radios. Each picks Narrow or Full for one kind of page. All three default to Narrow.
| Setting | Covers |
|---|---|
| Default width | archives, search, 404 — everything that is not a single page or post |
| Page default width | single pages |
| Post default width | single posts |
Narrow resolves to the narrow width (640px by default); Full resolves to the content width (1170px).
What to choose
A personal blog. Leave all three on Narrow. The default is the default for a reason.
A news or magazine site. Default width → Full, so the listing uses the whole container and thumbnails have room to be pictures rather than stamps. Post default width → Narrow, so articles keep their measure. This is the usual pairing, and the one the OwlDraft demo uses.
A site with landing pages. Page default width → Full, Post default width → Narrow. Then override the handful of text-only pages — About, Privacy — back to Narrow individually.
A featured first post hero always runs the full container width whatever the listing below it is set to, so you can lead with a wide hero over a narrow list.
Per page
One page can overrule Page default width for itself. Edit the page and use the Page options box:
| Default (Customizer) | no override — follows the setting above |
| Narrow | this page only |
| Full | this page only |
Default stores nothing at all, which is why changing the Customizer later still moves the page. See page options.
There is no per-post override. Posts are meant to look alike.
The footer follows
The footer has no width setting of its own. It takes whatever the content column above it resolved to, so the two always line up. A Full page gets a Full footer; a Narrow post gets a narrow one.
The header does not
The header bar always uses the content width, whatever the page below it does. A masthead that changed width from page to page would read as a bug.