Pages Router: CSS files with URL-encoded characters in path not served / not applied

This issue was created by an agent analysing CI failures from the Next.js Deploy Suite (vinext main vs Next.js v16.2.6, 2026-05-22).

Problem

A page importing CSS via a path that contains special characters (URL-encoded) should produce a blue background. The test observes the default transparent background, meaning the CSS resource at the URL-encoded path is either not served or the asset URL is encoded incorrectly so the browser never loads the file.

Expected background `rgb(0, 0, 255)`, received transparent

Estimated Impact

~1 test failures across the deploy suite.

Affected Test Suites

• test/e2e/app-dir/resource-url-encoding/resource-url-encoding.test.ts

Recommendation

1. Reproduce first in vinext's own test suite. Add a Pages Router fixture that imports ./styles/with space.css and assert the rendered page has the expected colour.

2. Round-trip the encoding. Make sure the emitted <link rel="stylesheet" href=...> URL is URL-encoded and that the static-asset server decodes paths before lookup, so the encoded URL resolves to the file on disk.