diff --git a/web/public/icons/icon-maskable-compact-512.png b/web/public/icons/icon-maskable-compact-512.png
new file mode 100644
index 0000000..57dcc06
Binary files /dev/null and b/web/public/icons/icon-maskable-compact-512.png differ
diff --git a/web/public/manifest.webmanifest b/web/public/manifest.webmanifest
index 36b652c..4928dd5 100644
--- a/web/public/manifest.webmanifest
+++ b/web/public/manifest.webmanifest
@@ -20,6 +20,12 @@
       "sizes": "512x512",
       "type": "image/png",
       "purpose": "any"
+    },
+    {
+      "src": "/icons/icon-maskable-compact-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "maskable"
     }
   ]
 }
diff --git a/web/tests/pwa-manifest.test.mjs b/web/tests/pwa-manifest.test.mjs
new file mode 100644
index 0000000..a6862ca
--- /dev/null
+++ b/web/tests/pwa-manifest.test.mjs
@@ -0,0 +1,18 @@
+import assert from 'node:assert/strict';
+import { readFile } from 'node:fs/promises';
+import test from 'node:test';
+
+test('PWA icons include a compact adaptive icon', async () => {
+  const manifest = JSON.parse(await readFile(new URL('../public/manifest.webmanifest', import.meta.url), 'utf8'));
+  for (const size of ['192x192', '512x512']) {
+    assert.ok(manifest.icons.some(icon => icon.sizes === size && (icon.purpose ?? 'any').split(/\s+/).includes('any')));
+  }
+  const maskable = manifest.icons.filter(icon => (icon.purpose ?? 'any').split(/\s+/).includes('maskable'));
+  assert.equal(maskable.length, 1);
+  assert.equal(maskable[0].sizes, '512x512');
+  assert.equal(maskable[0].type, 'image/png');
+  const image = await readFile(new URL(`../public${maskable[0].src}`, import.meta.url));
+  assert.ok(image.length <= 32 * 1024);
+  assert.equal(image.readUInt32BE(16), 512);
+  assert.equal(image.readUInt32BE(20), 512);
+});