Finish anatomy

A finish is atmosphere behind the words: a faint wash of the brand color in one corner, a grid so pale you notice it only when it is gone, a keyline around the page.

It is the layer that makes a deck feel like a document rather than a sequence of slides. It is also the layer most likely to ruin one, because a finish you notice is a finish that failed.

Turn the wash up until it ruins the slide

One finish, one layer

Try this. Change the FIRST 14% — the one inside --fin-wash — to 40%, then to 4%. (The second copy, in --fin-wash-opaque, is the export face and changes nothing on screen.) A layer covering the whole page lives at roughly 5–16%: below that it vanishes, above it it competes with the sentence. A narrow band can go higher.

Notice the color: the wash never names one. It is a mix of var(--accent) — your theme’s brand color — so the same finish recolors itself when the palette changes, and works on a dark canvas without a second version.

How an author turns one on

One line in the deck’s front matter:

---
theme: cuoio
finish: atrium
---

Ten values ship: none (the baseline), atrium, meridian, strata, halo, ledger, nimbus, loom, savile, gallery.

A busy slide can opt out on its own: .

Where it sits

The engine adds a backdrop layer as the first thing inside every finished slide, and paints the finish there — beneath everything the author wrote. Your content is never touched, never tinted, never moved.

┌─ section ──────────────────────────────┐
│  ┌─ .backdrop ──────────────────────┐  │  ← the finish paints here
│  │  wash · texture · mark · edge    │  │
│  └──────────────────────────────────┘  │
│  the heading, the words, the chart     │  ← untouched, painted above
└────────────────────────────────────────┘

Four layer roles, always in that order. The next page takes them one at a time.

Three things it is not

Not a theme. A theme sets the colors; a finish uses them. A finish that names a color of its own is broken by definition, because it will not follow the palette.

Not a component. A component arranges the content. A finish never touches the content.

Not mode:. That is the deck’s typographic hand — boardroom (the default) or one of the hand-drawn sketch modes. It is a separate front-matter key and composes freely with a finish:

mode: sketch
finish: atrium

The two get confused because sketch used to be a finish: value. It moved. finish: is backdrops only.

What a finish is made of

Gradients, almost entirely. A finish is a handful of linear-gradient and radial-gradient values assigned to named slots — plus, for two of the four layers, a string for the mark’s glyph and a stack of inset shadows for a full frame. No images, ever.

That constraint buys four things, and an image would cost all four. A gradient survives PDF export. It scales to any page size. It costs nothing to download, and it is still there when someone opens the file offline — where a fetched image is both missing and, in an exported document, a way for data to leak out. And because it is built from color-mix() of your theme’s tokens, it recolors itself when the palette changes.

The four layers, one at a time: The four layers.