# Duolingo gradient

Gradients derived from Duolingo'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/duolingo
- Brand colors: https://brandsweets.com/colors/brands/duolingo · Brand page: https://brandsweets.com/b/duolingo
- Palette: primary #58cc02, secondary #58cc02, accents #a5ed6e
- Source: https://duolingo.com (extracted 2026-09-02)

## Brand gradient

ΔE_OK 0.000 < 0.15 between #58cc02 and #58cc02 — a 2-stop would read as a flat fill, so this is a tonal ramp of #58cc02.

- CSS: `linear-gradient(135deg in oklch shorter hue, #9eff74 0%, #58cc02 50%, #298f00 100%)`
- Tailwind: `bg-linear-to-br/oklch from-[#9eff74] via-[#58cc02] to-[#298f00]`
- Contrast (worst point): white 1.24:1 fail · black 5.02:1 AA · banding high
- Maker: https://brandsweets.com/gradients/new/v1.9eff74-58cc02-298f00?a=135&in=oklch&hue=shorter

## Hero background

Chroma ×0.35 so it can carry text; ink black (inkFor at the midpoint). Passes AA for that ink at the worst point (4.83:1) without adjusting L.

- CSS: `linear-gradient(135deg in oklch shorter hue, #ccedc0 0%, #95ba88 50%, #63815d 100%)`
- Tailwind: `bg-linear-to-br/oklch from-[#ccedc0] via-[#95ba88] to-[#63815d]`
- Contrast (worst point): white 1.28:1 fail · black 4.83:1 AA · banding high · ink #000000
- Maker: https://brandsweets.com/gradients/new/v1.ccedc0-95ba88-63815d?a=135&in=oklch&hue=shorter

## 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. Black ink passes AA on the surface and both states (worst 7.82:1).

- CSS: `linear-gradient(180deg in oklch shorter hue, #66d926 0%, #4abf00 100%)`
- Tailwind: `bg-linear-to-b/oklch from-[#66d926] to-[#4abf00]`
- Contrast (worst point): white 1.82:1 fail · black 8.74:1 AA · banding high · ink #000000
- Maker: https://brandsweets.com/gradients/new/v1.66d926-4abf00?a=180&in=oklch&hue=shorter
- Hover: `linear-gradient(180deg in oklch shorter hue, #70e336 0%, #55c900 100%)`
- Active: `linear-gradient(180deg in oklch shorter hue, #5bcf0f 0%, #3fb500 100%)`

## Tonal ramp

- CSS: `linear-gradient(135deg in oklch shorter hue, #9eff74 0%, #58cc02 50%, #298f00 100%)`
- Tailwind: `bg-linear-to-br/oklch from-[#9eff74] via-[#58cc02] to-[#298f00]`
- Contrast (worst point): white 1.24:1 fail · black 5.02:1 AA · banding high
- Maker: https://brandsweets.com/gradients/new/v1.9eff74-58cc02-298f00?a=135&in=oklch&hue=shorter

## Analogous

Partner hue from the analogous rule at the source colour's lightness.

- CSS: `linear-gradient(135deg in oklab, #58cc02 0%, #b9b302 100%)`
- Tailwind: `bg-linear-to-br/oklab from-[#58cc02] to-[#b9b302]`
- Contrast (worst point): white 2.08:1 fail · black 9.49:1 AA · banding high
- Maker: https://brandsweets.com/gradients/new/v1.58cc02-b9b302?a=135

## Complementary

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, #58cc02 0%, #e07eff 100%)`
- Tailwind: `bg-linear-to-br/oklch from-[#58cc02] to-[#e07eff]`
- Contrast (worst point): white 2.00:1 fail · black 8.45:1 AA · banding medium
- Maker: https://brandsweets.com/gradients/new/v1.58cc02-e07eff?a=135&in=oklch&hue=shorter

## Triadic

Partner hue from the triadic rule at the source colour's lightness.

- CSS: `linear-gradient(135deg in oklab, #58cc02 0%, #77afff 100%)`
- Tailwind: `bg-linear-to-br/oklab from-[#58cc02] to-[#77afff]`
- Contrast (worst point): white 2.08:1 fail · black 9.34:1 AA · banding medium
- Maker: https://brandsweets.com/gradients/new/v1.58cc02-77afff?a=135

## CSS custom properties (brand.css)

```css
:root {
  /* Brand gradient (derived) */
  /* worst-case contrast: white 1.24:1, black 5.02:1 AA */
  --brand-gradient: linear-gradient(135deg in oklch shorter hue, #9eff74 0%, #58cc02 50%, #298f00 100%);
  /* hero — worst-case contrast: white 1.28:1, black 4.83:1 AA; ink passes AA at the worst point */
  --brand-gradient-hero: linear-gradient(135deg in oklch shorter hue, #ccedc0 0%, #95ba88 50%, #63815d 100%);
  --brand-gradient-hero-ink: #000000;
  /* button — worst-case contrast: white 1.82:1, black 8.74:1 AA */
  --brand-gradient-button: linear-gradient(180deg in oklch shorter hue, #66d926 0%, #4abf00 100%);
  --brand-gradient-button-hover: linear-gradient(180deg in oklch shorter hue, #70e336 0%, #55c900 100%);
  --brand-gradient-button-active: linear-gradient(180deg in oklch shorter hue, #5bcf0f 0%, #3fb500 100%);
  --brand-gradient-button-ink: #000000;
}
```

## 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.