/*
The site's page art: the accretion photographs behind a page, picked with
art-desert, art-closeup or art-enterprise beside .page. core.css lays the page
out and shades it; this only names the picture and frames it, so a binary that does not
register the backgrounds package (apps/talks) links neither the pictures nor a
rule pointing at them. shared.head links this after a page's other sheets when
it is registered, and core.css declares the layer it uses.

Each picture is AVIF with a WebP fallback. A browser takes the AVIF only where
image-set() can pick by type(), behind @supports: a custom property is not
checked where it is declared, so an image-set() the browser cannot read would
leave --page-art invalid and the page with no art at all. shared.head preloads
the art a page names (shared.Page_Art) with its image type.
*/
@layer layout {
	.page {
		&.art-desert {
			--page-art: url("/assets/backgrounds/accretion-desert-053778c9c082b44046e22b5c61c096a4d55538c884a2e59083d549c98849aebb.webp");

			background-position: 58% center;
		}

		&.art-closeup {
			--page-art: url("/assets/backgrounds/accretion-closeup-ff86031479871412bd69c9a16e55685463f2df0f9b4f5949b92cacc1292475b5.webp");

			background-position: center top;
		}

		&.art-enterprise {
			--page-art: url("/assets/backgrounds/enterprise-2f98e6bd44aca50058943bb6d1895c528423874b518c99544b749fdb18917d37.webp");

			background-position: center top;
		}
	}

	@supports (background-image: image-set(url("/assets/backgrounds/accretion-desert-420c16dda00a4c47086863a1e05f584bd38c603dac421f90af27e3743d4dc9be.avif") type("image/avif"))) {
		.page {
			&.art-desert {
				--page-art: image-set(
					url("/assets/backgrounds/accretion-desert-420c16dda00a4c47086863a1e05f584bd38c603dac421f90af27e3743d4dc9be.avif") type("image/avif"),
					url("/assets/backgrounds/accretion-desert-053778c9c082b44046e22b5c61c096a4d55538c884a2e59083d549c98849aebb.webp") type("image/webp")
				);
			}

			&.art-closeup {
				--page-art: image-set(
					url("/assets/backgrounds/accretion-closeup-8891e5ed981614b090f6367b3fdddab13fdd21a9ae303e61ac702a7d4f50adfe.avif") type("image/avif"),
					url("/assets/backgrounds/accretion-closeup-ff86031479871412bd69c9a16e55685463f2df0f9b4f5949b92cacc1292475b5.webp") type("image/webp")
				);
			}

			&.art-enterprise {
				--page-art: image-set(
					url("/assets/backgrounds/enterprise-e19ee25ee98d176c5a50134aeabc8f9cc197f53bc68a3fd661c3e271c9f81300.avif") type("image/avif"),
					url("/assets/backgrounds/enterprise-2f98e6bd44aca50058943bb6d1895c528423874b518c99544b749fdb18917d37.webp") type("image/webp")
				);
			}
		}
	}
}