Light Sash

Written for the variant you picked above: Lagoon

Write a WebGL1 full-screen fragment shader background (no libraries): one wide blade of light crossing the frame on a diagonal. Choose a direction about 34° above horizontal (the pointer turns it a little). For each pixel take along (the distance along the blade) and s (the signed distance across it, from a line passing right of centre), and wobble s with a slow sine along the blade and soft fBm. Layer the colours across s: a dim upper band (Gaussian at s ≈ 0.5), the coloured body (Gaussian at s ≈ 0.16, width 0.17), a slight darker channel just below it, a pale hot edge rising as s goes negative and a near-white haze beyond (smoothstep(−0.2, −0.62, s)). Streak the bands with fBm stretched along the blade and moving along it, like a long exposure. Darken the top-left slightly. Render through a small WebGL1 harness: a full-screen triangle, the device pixel ratio capped at 2 and scaled down (and about 30fps) on touch, paused offscreen and in hidden tabs, one still frame under reduced motion, the pointer eased in with a slow lerp and released when it leaves, and a CSS gradient fallback without WebGL. Add a little per-pixel noise so the gradients never band. An optional fade prop softens the bottom edge into the ground colour: a gradient to the ground plus a backdrop blur masked to grow towards the edge. Children sit above the canvas. Selected variant — Lagoon (lagoon): A teal blade with a mint edge and white-mint haze: bg #031a17, body #2a877e, edge #9ee6d6, haze #eefcf7. This selection takes precedence over references to other themes or options in the general brief. Implement this selected appearance; do not add a variant picker or alternative appearances unless requested. Implementation requirements: Use React and TypeScript. Keep the component self-contained, with uniquely scoped CSS and no animation libraries. Include required imports, styles and font setup in the result. Interaction: Move the pointer to turn the blade. Motion: The streaks flow along the blade and its edge wavers slowly. Reduced motion draws one still frame. Accessibility: Decorative and hidden from assistive tech. The upper-left is dark and suits white text; the lower-right is near white and suits dark text. Responsive behavior: Fills its container at any aspect ratio; device pixel ratio capped at 2. The optional fade softens the bottom edge into the ground colour. Touch: No pointer response on touch; the streaks keep flowing. Preserve keyboard access, visible focus and reduced-motion behavior. Keep fictional demo data and simulated service calls in a separate usage example; expose callbacks for real actions and recover from rejected requests. Keep usage-example links inside the demo: use local buttons or prevent navigation. Demonstration links must not navigate to Vitrine routes or open other pages; preserve real URL support in the reusable component itself. Verify the result at narrow and wide viewport sizes, with keyboard input and reduced motion enabled.

Notes

Interaction

Move the pointer to turn the blade.

Motion

The streaks flow along the blade and its edge wavers slowly. Reduced motion draws one still frame.

Accessibility

Decorative and hidden from assistive tech. The upper-left is dark and suits white text; the lower-right is near white and suits dark text.

Responsive

Fills its container at any aspect ratio; device pixel ratio capped at 2. The optional fade softens the bottom edge into the ground colour.

On touch

No pointer response on touch; the streaks keep flowing.