diff --git a/site/slides/package.json b/site/slides/package.json
index 7bcfcb8e..d4b0b6b8 100644
--- a/site/slides/package.json
+++ b/site/slides/package.json
@@ -6,7 +6,7 @@
   "description": "Short intro deck for ado-aw — Continuous AI for Azure DevOps",
   "scripts": {
     "dev": "slidev --open",
-    "build": "slidev build --base ./ --out ../public/slides",
+    "build": "slidev build --out ../public/slides && node postbuild.mjs ../public/slides",
     "export": "slidev export --wait 1500 --wait-until networkidle --output dist/ado-aw-intro.pdf"
   },
   "dependencies": {
diff --git a/site/slides/postbuild.mjs b/site/slides/postbuild.mjs
new file mode 100644
index 00000000..19cdd1f9
--- /dev/null
+++ b/site/slides/postbuild.mjs
@@ -0,0 +1,33 @@
+// Post-build step for the sub-path deployment of the Slidev deck.
+//
+// The deck is built with the default Vite base "/" so that Slidev's in-app
+// navigation (getSlidePath → import.meta.env.BASE_URL) produces clean hash
+// routes (/N and /presenter/N) for both play and presenter mode. JS/CSS asset
+// URLs are emitted relative via experimental.renderBuiltUrl (see vite.config.ts).
+//
+// The only thing left pointing at an absolute "/assets/…" path is the entry
+// markup in the generated HTML files. Rewrite those to "./assets/…" so the
+// bundle also loads correctly when served from …/ado-aw/slides/.
+import { readdir, readFile, writeFile } from 'node:fs/promises'
+import path from 'node:path'
+
+const outDir = process.argv[2]
+if (!outDir) {
+  console.error('usage: node postbuild.mjs <out-dir>')
+  process.exit(1)
+}
+
+const entries = await readdir(outDir, { withFileTypes: true })
+let patched = 0
+for (const e of entries) {
+  if (!e.isFile() || !e.name.endsWith('.html')) continue
+  const fp = path.join(outDir, e.name)
+  const src = await readFile(fp, 'utf8')
+  const out = src.replaceAll('="/assets/', '="./assets/')
+  if (out !== src) {
+    await writeFile(fp, out)
+    patched++
+    console.log(`  rewrote ${e.name}`)
+  }
+}
+console.log(`postbuild: relative-ized assets in ${patched} HTML file(s)`)
diff --git a/site/slides/vite.config.ts b/site/slides/vite.config.ts
new file mode 100644
index 00000000..d0e67c73
--- /dev/null
+++ b/site/slides/vite.config.ts
@@ -0,0 +1,17 @@
+import { defineConfig } from 'vite'
+
+// Deploy the deck under a sub-path (…/ado-aw/slides/) without breaking Slidev's
+// in-app navigation. Slidev's getSlidePath() prepends import.meta.env.BASE_URL
+// to every router target, so a non-"/" Vite base leaks into (or doubles in) the
+// route path — which breaks presenter mode in particular.
+//
+// Fix: keep the Vite base at "/" (so BASE_URL stays "/", and hash routes resolve
+// cleanly as /N and /presenter/N), but emit *relative* asset URLs via
+// renderBuiltUrl so the bundle still loads correctly from the sub-path.
+export default defineConfig({
+  experimental: {
+    renderBuiltUrl() {
+      return { relative: true }
+    },
+  },
+})