What the agent must do

• Use only if tokens.json has gradients: true; otherwise skip this look and say so.
• Draw one full-size fragment shader on a single canvas (raw WebGL with one triangle, no three.js unless the page already ships it), re-coloured from tokens.json accent, accent2, surface and bg; ignore the mesh-gradient skill's fixed blue palette.
• Keep motion slow (one cycle per 20–40 s), render at half resolution scaled up, and stop the loop when the canvas is off-screen or the tab is hidden.
• Text over the field must pass AA against the darkest and lightest point of the gradient; add a solid panel if it doesn't.
• Paint a static CSS gradient of the same colours first; mount the shader after first paint, and keep the static gradient under prefers-reduced-motion or when WebGL is unavailable.