# BBC gradient

Gradients derived from BBC's published colour tokens (nominative use; no brand assets). Deterministic: the same values are served as `--brand-gradient*` in the brand's brand.css.

- Page: https://brandsweets.com/gradients/brands/bbc-com
- Brand colors: https://brandsweets.com/colors/brands/bbc-com · Brand page: https://brandsweets.com/b/bbc-com
- Palette: primary #000000, secondary #0071f1, accents #0000ee
- Source: https://bbc.com (extracted 2026-09-02)

## Brand gradient

- CSS: `linear-gradient(135deg in oklab, #000000 0%, #0071f1 100%)`
- Tailwind: `bg-linear-to-br/oklab from-[#000000] to-[#0071f1]`
- Contrast (worst point): white 4.53:1 AA · black 1.00:1 fail · banding medium
- Maker: https://brandsweets.com/gradients/new/v1.000000-0071f1?a=135

## Hero background

Chroma ×0.35 so it can carry text; ink white (inkFor at the midpoint). L shifted −0.01 until the ink passes AA at the worst point (4.58:1).

- CSS: `linear-gradient(135deg in oklab, #000000 0%, #5a77a1 100%)`
- Tailwind: `bg-linear-to-br/oklab from-[#000000] to-[#5a77a1]`
- Contrast (worst point): white 4.58:1 AA · black 1.00:1 fail · banding medium · ink #ffffff
- Maker: https://brandsweets.com/gradients/new/v1.000000-5a77a1?a=135

## Button / CTA

ΔL 0.08 top→bottom in the primary's hue (a lit surface, not a rainbow); hover L +0.03, active L −0.03. White ink passes AA on the surface and both states (worst 19.91:1).

- CSS: `linear-gradient(180deg in oklch shorter hue, #090909 0%, #010101 100%)`
- Tailwind: `bg-linear-to-b/oklch from-[#090909] to-[#010101]`
- Contrast (worst point): white 19.91:1 AA · black 1.01:1 fail · banding high · ink #ffffff
- Maker: https://brandsweets.com/gradients/new/v1.090909-010101?a=180&in=oklch&hue=shorter
- Hover: `linear-gradient(180deg in oklch shorter hue, #090909 0%, #010101 100%)`
- Active: `linear-gradient(180deg in oklch shorter hue, #090909 0%, #010101 100%)`

## Tonal ramp

- CSS: `linear-gradient(135deg in oklch shorter hue, #3d3d3d 0%, #000000 100%)`
- Tailwind: `bg-linear-to-br/oklch from-[#3d3d3d] to-[#000000]`
- Contrast (worst point): white 10.86:1 AA · black 1.00:1 fail · banding medium
- Maker: https://brandsweets.com/gradients/new/v1.3d3d3d-000000?a=135&in=oklch&hue=shorter

## Analogous

Primary #000000 is achromatic — harmony rotates #0071f1 instead. Partner hue from the analogous rule at the source colour's lightness.

- CSS: `linear-gradient(135deg in oklab, #0071f1 0%, #0084ac 100%)`
- Tailwind: `bg-linear-to-br/oklab from-[#0071f1] to-[#0084ac]`
- Contrast (worst point): white 4.28:1 AA-large · black 4.62:1 AA · banding high
- Maker: https://brandsweets.com/gradients/new/v1.0071f1-0084ac?a=135

## Complementary

Primary #000000 is achromatic — harmony rotates #0071f1 instead. Partner hue from the complementary rule at the source colour's lightness. ΔH 180° > 140° — interpolating in oklch (shorter hue) keeps the midpoint saturated.

- CSS: `linear-gradient(135deg in oklch shorter hue, #0071f1 0%, #9f6e00 100%)`
- Tailwind: `bg-linear-to-br/oklch from-[#0071f1] to-[#9f6e00]`
- Contrast (worst point): white 3.94:1 AA-large · black 4.63:1 AA · banding medium
- Maker: https://brandsweets.com/gradients/new/v1.0071f1-9f6e00?a=135&in=oklch&hue=shorter

## Triadic

Primary #000000 is achromatic — harmony rotates #0071f1 instead. Partner hue from the triadic rule at the source colour's lightness.

- CSS: `linear-gradient(135deg in oklab, #0071f1 0%, #df0042 100%)`
- Tailwind: `bg-linear-to-br/oklab from-[#0071f1] to-[#df0042]`
- Contrast (worst point): white 4.51:1 AA · black 4.20:1 AA-large · banding medium
- Maker: https://brandsweets.com/gradients/new/v1.0071f1-df0042?a=135

## CSS custom properties (brand.css)

```css
:root {
  /* Brand gradient (derived) */
  /* worst-case contrast: white 4.53:1 AA, black 1.00:1 */
  --brand-gradient: linear-gradient(135deg in oklab, #000000 0%, #0071f1 100%);
  /* hero — worst-case contrast: white 4.58:1 AA, black 1.00:1; ink passes AA at the worst point */
  --brand-gradient-hero: linear-gradient(135deg in oklab, #000000 0%, #5a77a1 100%);
  --brand-gradient-hero-ink: #ffffff;
  /* button — worst-case contrast: white 19.91:1 AA, black 1.01:1 */
  --brand-gradient-button: linear-gradient(180deg in oklch shorter hue, #090909 0%, #010101 100%);
  --brand-gradient-button-hover: linear-gradient(180deg in oklch shorter hue, #090909 0%, #010101 100%);
  --brand-gradient-button-active: linear-gradient(180deg in oklch shorter hue, #090909 0%, #010101 100%);
  --brand-gradient-button-ink: #ffffff;
}
```

## Gradient maker

Every maker URL is the gradient's state: `/gradients/new/v1.<hex>-<hex>[_pos]?a=135&in=oklch&hue=shorter&e=soft&g=8`. Hand one to a human, let them refine, and read the link they return.

## Connect an agent

Point any MCP client at the BrandSweets gradients endpoint for the same engine and corpus:

- Endpoint: https://mcp.brandsweets.com/gradients/mcp
- Tools: `make_gradient` (2–5 colours → CSS with the interpolation space, Tailwind v4, SVG, PNG URL, DTCG token + the contrast/banding/gamut report), `brand_gradients` (brand slug or palette → brand gradient, hero, button, variants).
- Resource: `gradients://corpus` — the whole bundled corpus as JSON.