diff --git a/src/soundUtils.test.ts b/src/soundUtils.test.ts
index 3d9810fe0..c6b652f9d 100644
--- a/src/soundUtils.test.ts
+++ b/src/soundUtils.test.ts
@@ -34,23 +34,6 @@ describe("prefetchSounds", () => {
     expect(bytesOf(sounds.beep)).toEqual([1, 2, 3]);
   });
 
-  it("decodes base64 data: URLs without fetching them", async () => {
-    // "OggS" — the bytes 0x4f 0x67 0x67 0x53
-    const sounds = await prefetchSounds({
-      beep: { ogg: "data:audio/ogg;base64,T2dnUw==" },
-    });
-    expect(fetchSpy).not.toHaveBeenCalled();
-    expect(bytesOf(sounds.beep)).toEqual([0x4f, 0x67, 0x67, 0x53]);
-  });
-
-  it("leaves out a sound with a percent-encoded data: URL", async () => {
-    const sounds = await prefetchSounds({
-      beep: { ogg: "data:audio/ogg,Ogg%53" },
-    });
-    expect(fetchSpy).not.toHaveBeenCalled();
-    expect(sounds).toEqual({});
-  });
-
   it("leaves out a sound whose response is not okay", async () => {
     fetchSpy.mockResolvedValue(new Response(null, { status: 404 }));
     const sounds = await prefetchSounds({
@@ -60,18 +43,16 @@ describe("prefetchSounds", () => {
   });
 
   it("leaves out a sound that fails to load, keeping the others", async () => {
-    fetchSpy.mockRejectedValue(new TypeError("Failed to fetch"));
+    // Fetched in the order given
+    fetchSpy
+      .mockRejectedValueOnce(new TypeError("Failed to fetch"))
+      .mockResolvedValueOnce(
+        new Response(new Uint8Array([1, 2, 3]), { status: 200 }),
+      );
     const sounds = await prefetchSounds({
       beep: { ogg: "https://example.org/beep.ogg" },
-      boop: { ogg: "data:audio/ogg;base64,T2dnUw==" },
+      boop: { ogg: "https://example.org/boop.ogg" },
     });
     expect(Object.keys(sounds)).toEqual(["boop"]);
   });
-
-  it("leaves out a sound with a malformed data: URL", async () => {
-    const sounds = await prefetchSounds({
-      beep: { ogg: "data:audio/ogg;base64" },
-    });
-    expect(sounds).toEqual({});
-  });
 });
diff --git a/src/soundUtils.ts b/src/soundUtils.ts
index 74d2ea33c..7ace7876e 100644
--- a/src/soundUtils.ts
+++ b/src/soundUtils.ts
@@ -32,38 +32,12 @@ function getPreferredAudioFormat(): "ogg" | "mp3" {
 
 const preferredFormat = getPreferredAudioFormat();
 
-/**
- * Decode a `data:` URL into the bytes it carries.
- *
- * The component build inlines the sound files as `data:` URLs. Those could be
- * `fetch`ed like any other URL, but that fetch is subject to the host page's
- * Content Security Policy, and `connect-src` lists rarely allow `data:` (a `*`
- * source does not cover it). Reading the bytes out of the URL directly needs no
- * network access, so no policy can stop it.
- * @param url The `data:` URL to decode.
- * @returns The decoded bytes.
- */
-function decodeDataUrl(url: string): ArrayBuffer {
-  const separator = url.indexOf(",");
-  if (!url.startsWith("data:") || separator === -1)
-    throw new Error("Not a valid data: URL");
-  const header = url.slice("data:".length, separator);
-  // Vite only percent-encodes SVGs; every other inlined asset is base64.
-  if (!header.split(";").includes("base64"))
-    throw new Error("Only base64 data: URLs are supported");
-  // `decoded` is a binary string: one char per byte
-  const decoded = atob(url.slice(separator + 1));
-  const bytes = Uint8Array.from(decoded, (c) => c.charCodeAt(0));
-  return bytes.buffer;
-}
-
 /**
  * Load the bytes of a single sound file.
- * @param url Where the sound is: an ordinary URL to fetch, or a `data:` URL.
+ * @param url Where the sound is.
  * @returns The bytes, or null if the sound could not be loaded.
  */
 async function loadSound(url: string): Promise<ArrayBuffer | null> {
-  if (url.startsWith("data:")) return decodeDataUrl(url);
   const response = await fetch(url);
   if (isFailure(response)) return null;
   return await response.arrayBuffer();
diff --git a/vite-component.config.ts b/vite-component.config.ts
index fc0c9ac4a..859d2f5ff 100644
--- a/vite-component.config.ts
+++ b/vite-component.config.ts
@@ -6,6 +6,7 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { defineConfig } from "vite";
+import { posix } from "node:path";
 
 import { vitePluginsConfig } from "./vite.config.ts";
 import { scopeStylesToRoot } from "./component/build/scopeStylesToRoot.ts";
@@ -41,14 +42,17 @@ export default defineConfig(({ mode }) => {
     // imports do.)
     base: "./",
     experimental: {
-      // Spelled `./assets/…`, not `assets/…` as the relative base would have it:
-      // a host's bundler reads a bare name as a package to look up.
-      renderBuiltUrl: (filename, { hostType }) =>
-        hostType === "js"
-          ? {
-              runtime: `new URL(${JSON.stringify(`./${filename}`)}, import.meta.url).href`,
-            }
-          : { relative: true },
+      // Relative to the chunk that references it, wherever that chunk lands,
+      // and spelled `./assets/…` rather than `assets/…`: a host's bundler reads
+      // a bare name as a package to look up.
+      renderBuiltUrl: (filename, { hostId, hostType }) => {
+        if (hostType !== "js") return { relative: true };
+        const relative = posix.relative(posix.dirname(hostId), filename);
+        const specifier = relative.startsWith(".") ? relative : `./${relative}`;
+        return {
+          runtime: `new URL(${JSON.stringify(specifier)}, import.meta.url).href`,
+        };
+      },
     },
     // A host's document is not ours to style: everything in the stylesheet is
     // confined to the element Element Call is mounted in