Placeholder material

Registry items ship with stand-in content: a rectangle where the user's screenshot goes, a bar where their number goes, a chip where their teammate's face goes. That stand-in is placeholder material, and it is monochrome. No hue, no colour ramps, no purple-to-blue diagonal fill.

The rule exists because placeholder colour is always arbitrary. A violet card, a blue logo tile and a rainbow avatar row assert a brand the composition does not have; across 250 items the same three arbitrary hues become the catalog's identity instead of the author's. Value says everything colour was saying here, and says it truthfully.

The one rule

Placeholder content carries no hue. It is built from four alpha steps of the composition's own ink over the composition's own ground, plus a hairline. Accent marks one element per composition, and never a placeholder.

The ramp

Four fill steps and a hairline. All of them are the ink at an alpha, so the ramp inverts for free on dark themes and needs no second table.

Write them the way the file already writes colour:

/* theme-token primitives (--fg / --surface available) */
background: color-mix(in srgb, var(--fg, #f8fafc) 18%, transparent);

/* fixed-palette ports (local --hf-ink, no theme tokens) */
background: rgba(17, 24, 39, 0.18);

Four steps, not eight. Grays go muddy when adjacent steps sit close together, so every step is at least 1.6x the alpha of the one below it. Reaching for a fifth value is the signal that the layout, not the palette, needs the work. Snap to the nearest step instead.

Contrast, measured against both shipped grounds (neutral light #fcfcfd, bold dark #1b1230): L1 is 7.7:1 / 8.9:1, L2 is 3.1:1 / 4.4:1, L3 and L4 are below 3:1 by design. Therefore text never goes below L1, and L2 is the floor for any graphic a viewer has to compare (a chart series, a state indicator). L3 and L4 are for surfaces only.

Depth without colour

In priority order. Reach for the first one that works.

1. Value step. Nothing sits on the same step as its ground. One full step of separation minimum. This alone resolves most stacking.
2. Hairline. 1px of hair on every plate boundary. A border separates two surfaces more cleanly than a gradient ever did, and survives video compression that eats a soft edge.
3. Negative space. Padding is elevation. A plate with --space-2 inside it reads as raised without any fill difference at all.
4. Texture, at the finest grain only. A repeating-linear-gradient at L3-and-below, period 2-4px, achromatic. This is the one thing value cannot say: a flat gray rectangle reads as an empty box, the same rectangle finely hatched reads as a surface with content on it. Use it to mark media, nothing else.

Shadows are allowed and must be achromatic and diffuse: 0 Npx 3Npx rgba(0,0,0,0.18). Never a coloured glow; a glow is an accent wearing a shadow's clothes.

Reading each kind in black and white

A gray rectangle has to still say screen and not image. Shape, aspect, glyph and texture carry the meaning that hue was carrying badly.

Circle means person, rounded square means app or brand. Keeping those two shapes distinct is what lets both live at the same value step without ambiguity.

Why no gradient inside a chart bar: a vertical light-to-dark fill makes every bar lighter at its top, so the tallest bar reads palest exactly where the eye lands to compare heights. The decoration contradicts the data. Flat fills are both plainer and more honest.

Accent

The accent enum stays. green rides --brand, blue rides --accent, violet rides --accent-2, exactly as before, and every declared accent or tone variable keeps working unchanged. What changes is where accent is allowed to land:

Accent marks at most one element per composition, and only where the accent is the meaning: the selected tier, the current step, the figure a count-up lands on, the ink of a stroke being drawn. Placeholder content is never accent-coloured.

Fixed-palette ports have no theme tokens, so they get the accent through their own variable with a neutral fallback:

/* was: --hf-accent: #2563eb; */
--hf-accent: var(--accent, #18181b);

Unthemed, the item renders in pure black and white. Drop it into a themed composition and the author's accent lands on that one element and nowhere else. Where the accent is chosen by an enum, the lookup table maps to tokens, never to hex: green to var(--brand, <neutral>), blue to var(--accent, <neutral>), violet to var(--accent-2, <neutral>). The enum's declared options and default are unchanged, so no mount breaks.

"One element" means one role, not one node: an app mark repeated on three devices of the same mock is still one element.

Killing accent outright was the alternative and it is worse. Accent is already load-bearing in exactly the cases where it is correct, and it is the only hook an author has for their own brand; removing it would push those cases into value tricks for a job one hue does better with one element. The failure was never that accent existed, it was that accent had become the default fill for every placeholder. Capping it at one element fixes the failure with no variable migration.

Gradients that stay

The ban is on hue-carrying fills, not on the CSS function. These are material, not placeholder, and flattening them breaks the thing the item exists to do:

• Physical surfaces — device bezels, brushed metal, glass, a screen's inner vignette.
• Sheens and sweeps — linear-gradient(90deg, transparent, rgba(255,255,255,0.75), transparent) driven across an element. That is motion, not decoration.
• Scrims and vignettes — rgba(0,0,0,α) ramps that buy text contrast over media.
• Effects whose subject is the gradient — aurora, liquid glass, chromatic aberration, grain fields, shader transitions. The gradient is the product.

All four are achromatic or physically motivated. If a gradient is neither, it is placeholder slop and it goes.

Checklist

• [ ] No #7c3aed, #2563eb, #6366f1, #8b5cf6, #a855f7, #4f46e5 anywhere in the item.
• [ ] Every placeholder fill is ink at 72 / 45 / 18 / 8 / 14 percent, and nothing else.
• [ ] At most one accent-coloured element, and it means something.
• [ ] Text sits at L1 or above; L3 and L4 carry no text.
• [ ] Every remaining gradient is a surface, a sweep, a scrim, or the effect itself.
• [ ] hyperframes check passes, and a rendered frame was looked at.