diff --git a/web/public/icons/apple-touch-icon.png b/web/public/icons/apple-touch-icon.png
index 29f27f2..2396703 100644
Binary files a/web/public/icons/apple-touch-icon.png and b/web/public/icons/apple-touch-icon.png differ
diff --git a/web/public/icons/icon-192.png b/web/public/icons/icon-192.png
index aa4dd6e..c999ea4 100644
Binary files a/web/public/icons/icon-192.png and b/web/public/icons/icon-192.png differ
diff --git a/web/public/icons/icon-512-maskable.png b/web/public/icons/icon-512-maskable.png
index dae4909..2b2486c 100644
Binary files a/web/public/icons/icon-512-maskable.png and b/web/public/icons/icon-512-maskable.png differ
diff --git a/web/public/icons/icon-512.png b/web/public/icons/icon-512.png
index 6f1b20f..785a579 100644
Binary files a/web/public/icons/icon-512.png and b/web/public/icons/icon-512.png differ
diff --git a/web/public/icons/logo.png b/web/public/icons/logo.png
index b8851be..79e060b 100644
Binary files a/web/public/icons/logo.png and b/web/public/icons/logo.png differ
diff --git a/web/public/sw.js b/web/public/sw.js
index 5950ece..975fdb3 100644
--- a/web/public/sw.js
+++ b/web/public/sw.js
@@ -1,5 +1,5 @@
 // Ham Lab service worker: cache hashed assets, never the API, network-first for the shell.
-const CACHE = 'hamlab-v2';
+const CACHE = 'hamlab-v3'; // bumped when files under /icons/ change: they are served cache-first
 self.addEventListener('install', () => self.skipWaiting());
 self.addEventListener('activate', (e) => {
   e.waitUntil(caches.keys().then((ks) => Promise.all(ks.filter((k) => k !== CACHE).map((k) => caches.delete(k)))).then(() => self.clients.claim()));
diff --git a/web/scripts/icons.mjs b/web/scripts/icons.mjs
index 9f102f7..4f00eff 100644
--- a/web/scripts/icons.mjs
+++ b/web/scripts/icons.mjs
@@ -1,26 +1,68 @@
-// Renders the PWA icons with node-canvas (borrowed from ../../calorie-counter/node_modules).
+// Renders the PWA icon set and the login logo from scripts/logo-source.png, with node-canvas
+// (borrowed from ../../calorie-counter/node_modules).   node scripts/icons.mjs
+//
+// The artwork is a rounded square on a transparent background, a little off-centre in its
+// file. It is trimmed to its own edge, then drawn three ways:
+//   icon-192 / icon-512 / logo   the artwork alone, transparent corners, filling the square
+//   apple-touch-icon             iOS paints transparency black and cuts its own, tighter
+//                                corners: a dark ground from the artwork's own palette, the
+//                                artwork inset a little so its neon ring clears that cut
+//   icon-512-maskable            Android may crop to a circle 80% across: the whole artwork
+//                                sits inside that circle, on the same dark ground to the edge
 import { createRequire } from 'node:module'
 import { writeFileSync } from 'node:fs'
 const require = createRequire(import.meta.url)
-const { createCanvas } = require('/home/core/projects/calorie-counter/node_modules/canvas')
+const { createCanvas, loadImage } = require('/home/core/projects/calorie-counter/node_modules/canvas')
 
-function draw(size, { pad = 0, radius = 0 }) {
-  const c = createCanvas(size, size), g = c.getContext('2d')
-  g.fillStyle = '#111418'
-  if (radius) { g.beginPath(); g.roundRect(0, 0, size, size, radius); g.fill() } else g.fillRect(0, 0, size, size)
-  const inner = size - pad * 2
-  g.fillStyle = '#e3a33b'
-  g.font = `bold ${inner * 0.62}px "DejaVu Serif", serif`
-  g.textAlign = 'center'; g.textBaseline = 'middle'
-  g.fillText('H', size / 2, size / 2 + inner * 0.03)
-  // prompt caret
-  g.fillStyle = '#58a6ff'
-  g.font = `bold ${inner * 0.22}px "DejaVu Sans Mono", monospace`
-  g.fillText('>_', size / 2 + inner * 0.27, size / 2 + inner * 0.27)
-  return c.toBuffer('image/png')
+const img = await loadImage(new URL('./logo-source.png', import.meta.url).pathname)
+const src = createCanvas(img.width, img.height), sg = src.getContext('2d')
+sg.drawImage(img, 0, 0)
+const px = sg.getImageData(0, 0, img.width, img.height), d = px.data
+// The export left the artwork at alpha 252 and a stray alpha-1 speck outside it: make what
+// is there fully there, what isn't fully gone, and keep the anti-aliased edge between.
+let x0 = img.width, y0 = img.height, x1 = 0, y1 = 0
+for (let y = 0; y < img.height; y++) for (let x = 0; x < img.width; x++) {
+  const i = (y * img.width + x) * 4 + 3
+  if (d[i] >= 240) d[i] = 255; else if (d[i] < 8) d[i] = 0
+  if (d[i] > 128) { if (x < x0) x0 = x; if (x > x1) x1 = x; if (y < y0) y0 = y; if (y > y1) y1 = y }
 }
-writeFileSync('public/icons/icon-192.png', draw(192, {}))
-writeFileSync('public/icons/icon-512.png', draw(512, {}))
-writeFileSync('public/icons/icon-512-maskable.png', draw(512, { pad: 80 }))
-writeFileSync('public/icons/apple-touch-icon.png', draw(180, {}))
-console.log('icons written')
+sg.putImageData(px, 0, 0)
+// a square around the artwork's own centre, as wide as its longer side: never stretched
+const side = Math.max(x1 - x0, y1 - y0) + 1, cx = (x0 + x1) / 2, cy = (y0 + y1) / 2
+const art = createCanvas(side, side)
+art.getContext('2d').drawImage(src, Math.round(cx - side / 2), Math.round(cy - side / 2), side, side, 0, 0, side, side)
+
+// Shrinking six-fold in one step aliases the fine lines; halving until close does not.
+function shrink(from, size) {
+  let cur = from
+  while (cur.width / 2 >= size) {
+    const next = createCanvas(Math.ceil(cur.width / 2), Math.ceil(cur.height / 2)), g = next.getContext('2d')
+    g.imageSmoothingEnabled = true; g.imageSmoothingQuality = 'high'; g.quality = 'best'; g.patternQuality = 'best'
+    g.drawImage(cur, 0, 0, next.width, next.height)
+    cur = next
+  }
+  return cur
+}
+
+function draw(size, { scale = 1, ground = false } = {}) {
+  const c = createCanvas(size, size), g = c.getContext('2d')
+  if (ground) { // the artwork's own night-green, lit a little behind the middle
+    const bg = g.createRadialGradient(size / 2, size / 2, 0, size / 2, size / 2, size * 0.72)
+    bg.addColorStop(0, '#0b2e2a'); bg.addColorStop(1, '#03110f')
+    g.fillStyle = bg; g.fillRect(0, 0, size, size)
+  }
+  const w = Math.round(size * scale), from = shrink(art, w)
+  g.imageSmoothingEnabled = true; g.imageSmoothingQuality = 'high'; g.quality = 'best'; g.patternQuality = 'best'
+  g.drawImage(from, (size - w) / 2, (size - w) / 2, w, w)
+  return c.toBuffer('image/png', { compressionLevel: 9 })
+}
+
+const out = {
+  'icon-192.png': draw(192),
+  'icon-512.png': draw(512),
+  'logo.png': draw(480),
+  'apple-touch-icon.png': draw(180, { scale: 0.95, ground: true }),
+  'icon-512-maskable.png': draw(512, { scale: 0.68, ground: true }),
+}
+for (const [name, buf] of Object.entries(out)) { writeFileSync(new URL('../public/icons/' + name, import.meta.url).pathname, buf); console.log(name, Math.round(buf.length / 1024) + ' KB') }
+console.log(`artwork ${x1 - x0 + 1}×${y1 - y0 + 1} at ${x0},${y0} → ${side} px square`)
diff --git a/web/scripts/logo-source.png b/web/scripts/logo-source.png
new file mode 100644
index 0000000..146393a
Binary files /dev/null and b/web/scripts/logo-source.png differ
diff --git a/web/src/Login.tsx b/web/src/Login.tsx
index 6b4026a..5ea67a4 100644
--- a/web/src/Login.tsx
+++ b/web/src/Login.tsx
@@ -17,7 +17,7 @@ export default function Login({ onLogin }: { onLogin: () => void }) {
   return (
     <div className="center">
       <form className="login" onSubmit={submit}>
-        <img className="login-logo" src="/icons/logo.png" alt="" width={160} height={160} />
+        <img className="login-logo" src="/icons/logo.png" alt="" width={176} height={176} />
         <h1>Ham Lab</h1>
         <input type="password" autoFocus autoComplete="current-password" placeholder="password"
           value={pw} onChange={(e) => setPw(e.target.value)} disabled={busy} />
diff --git a/web/src/styles.css b/web/src/styles.css
index f15832f..278fc7c 100644
--- a/web/src/styles.css
+++ b/web/src/styles.css
@@ -16,7 +16,9 @@ button { font: inherit; color: inherit; background: none; border: 0; cursor: poi
 
 /* login */
 .login { display: flex; flex-direction: column; gap: 10px; width: min(320px, 90vw); }
-.login-logo { width: 160px; height: 160px; align-self: center; border-radius: 50%; margin-bottom: 4px; }
+/* the logo carries the wordmark now; the heading stays for screen readers and is not drawn twice */
+.login h1 { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
+.login-logo { width: 176px; height: 176px; align-self: center; margin-bottom: 4px; } /* the artwork brings its own shape: no circular crop */
 .login h1 { text-align: center;  margin: 0 0 8px; font-weight: 600; color: var(--accent); letter-spacing: .5px; }
 .login input { padding: 10px 12px; background: var(--bg2); border: 1px solid var(--border); border-radius: 6px; color: var(--fg); font-size: 16px; }
 .login button, .primary { padding: 10px 12px; background: var(--accent); color: var(--btn-fg); border-radius: 6px; font-weight: 600; }