From 0fd49c08faebd3d6d71e536b096fea103f433e0c Mon Sep 17 00:00:00 2001
From: Bendik Aagaard Lynghaug <bendik.lynghaug@gmail.com>
Date: Tue, 25 Aug 2026 17:24:14 +0200
Subject: [PATCH] Content-owned hero module (WIP branch for local verification)

---
 hero.js   | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 site.yaml |   9 ++--
 2 files changed, 137 insertions(+), 6 deletions(-)
 create mode 100644 hero.js

diff --git a/hero.js b/hero.js
new file mode 100644
index 0000000..f08240e
--- /dev/null
+++ b/hero.js
@@ -0,0 +1,134 @@
+// redoal.com's hero: "sine swings" - the drifting layered sine paths
+// from lysbue's logo (the site this content descends from), grown from
+// a clipped 400px circle into a full-width band. No input: the form's
+// gesture canvas below is the one place a visitor draws. Content-owned:
+// portal knows only site.yaml's `hero: {kind: module, module: hero.js}`
+// and the contract - `mount(container) -> handle` with `stop()`; it
+// serves this file same-origin at /site/hero.js, starts it at HTML
+// parse time, adopts it on hydration, and stops it on navigation.
+//
+// Pure SVG + CSS: the strokes take their color from portal's own
+// custom properties (--accent, --ink-dim), so both themes come for
+// free and there's no palette copy to keep in sync. Motion is a CSS
+// keyframe on each layer's transform, disabled under
+// prefers-reduced-motion.
+
+const STYLE_ID = 'redoal-hero-style';
+
+// One period is 400 units wide; the path is written two periods long
+// so translating by exactly one period loops seamlessly.
+const SWING =
+    'M 0 200 Q 100 100 200 200 Q 300 300 400 200 ' +
+    'Q 500 100 600 200 Q 700 300 800 200 ' +
+    'Q 900 100 1000 200 Q 1100 300 1200 200';
+
+// (y offset, stroke width, opacity, seconds per period, direction)
+const LAYERS = [
+    [0, 6.5, 0.55, 9, 1],
+    [7, 3, 0.45, 11, 1],
+    [9, 1, 0.5, 13, 1],
+    [15, 0.5, 0.6, 17, 1],
+    [-60, 1.5, 0.18, 23, -1],
+    [70, 1, 0.14, 29, -1],
+];
+
+const CSS = `
+.redoal-hero {
+  position: absolute;
+  inset: 0;
+  overflow: hidden;
+  pointer-events: none;
+}
+.redoal-hero svg {
+  position: absolute;
+  inset: 0;
+  width: 100%;
+  height: 100%;
+}
+.redoal-hero .swing {
+  fill: none;
+  stroke: var(--accent);
+  stroke-linecap: round;
+  animation: redoal-swing var(--dur) linear infinite;
+  animation-direction: var(--dir);
+}
+.redoal-hero .swing.far {
+  stroke: var(--ink-dim);
+}
+@keyframes redoal-swing {
+  from { transform: translateX(0); }
+  to { transform: translateX(-400px); }
+}
+@media (prefers-reduced-motion: reduce) {
+  .redoal-hero .swing { animation: none; }
+}
+`;
+
+function ensureStyle() {
+    if (document.getElementById(STYLE_ID)) return;
+    const style = document.createElement('style');
+    style.id = STYLE_ID;
+    style.textContent = CSS;
+    document.head.appendChild(style);
+}
+
+const NS = 'http://www.w3.org/2000/svg';
+
+class SineSwings {
+    constructor(container) {
+        ensureStyle();
+        this.root = document.createElement('div');
+        this.root.className = 'redoal-hero';
+        this.root.setAttribute('aria-hidden', 'true');
+
+        // viewBox 400 wide per period; preserveAspectRatio "slice" so
+        // the band always fills the box and the loop is seamless at
+        // any width - the SVG is 1200 wide but only translates by 400.
+        const svg = document.createElementNS(NS, 'svg');
+        svg.setAttribute('viewBox', '0 0 800 400');
+        svg.setAttribute('preserveAspectRatio', 'xMidYMid slice');
+
+        // The logo's clipped circle, centered - the near layers live
+        // inside it; the far layers drift across the whole band.
+        const defs = document.createElementNS(NS, 'defs');
+        const clip = document.createElementNS(NS, 'clipPath');
+        clip.id = 'redoal-hero-clip';
+        const circle = document.createElementNS(NS, 'circle');
+        circle.setAttribute('cx', '400');
+        circle.setAttribute('cy', '200');
+        circle.setAttribute('r', '150');
+        clip.appendChild(circle);
+        defs.appendChild(clip);
+        svg.appendChild(defs);
+
+        const far = document.createElementNS(NS, 'g');
+        const near = document.createElementNS(NS, 'g');
+        near.setAttribute('clip-path', 'url(#redoal-hero-clip)');
+        // The logo's tilt.
+        near.setAttribute('transform', 'rotate(-13 400 200)');
+
+        for (const [dy, width, opacity, dur, dir] of LAYERS) {
+            const path = document.createElementNS(NS, 'path');
+            path.setAttribute('d', SWING);
+            path.setAttribute('stroke-width', String(width));
+            path.setAttribute('opacity', String(opacity));
+            path.setAttribute('transform', `translate(-200 ${dy})`);
+            const isFar = Math.abs(dy) > 30;
+            path.setAttribute('class', isFar ? 'swing far' : 'swing');
+            path.style.setProperty('--dur', `${dur}s`);
+            path.style.setProperty('--dir', dir < 0 ? 'reverse' : 'normal');
+            (isFar ? far : near).appendChild(path);
+        }
+        svg.append(far, near);
+        this.root.appendChild(svg);
+        container.appendChild(this.root);
+    }
+
+    stop() {
+        this.root.remove();
+    }
+}
+
+export function mount(container) {
+    return new SineSwings(container);
+}
diff --git a/site.yaml b/site.yaml
index c8e28c1..4a4f33e 100644
--- a/site.yaml
+++ b/site.yaml
@@ -1,9 +1,6 @@
-# Instance branding - see the schema notes in this repo's README and
-# portal's content loader (src/content.rs, SiteConfig). The relay URL
-# here drives the landing hero's ambient echoes; the same URL appears
-# on index.yaml's gesture requirement for the form widget.
+# Instance branding - see uhhm/questions' README for the schema.
 title: redoal
 wordmark: https://project.uhhm.no/redoal/questions/raw/branch/main/wordmark.svg
 hero:
-  kind: gesture
-  relay: wss://relay.redoal.com
+  kind: module
+  module: hero.js   # this repo's sine-swings piece, served at /site/hero.js