Inconsistent parsing of data URLs in CSS in Next 14

[prichey]

Link to the code that reproduces this issue

codemirror / https://github.com/prichey/css-bug-repro

To Reproduce

1. next dev
2. Note which divs have the incorrect background CSS (.blue-bg, .pink-bg).

Current vs. Expected behavior

Using a 'partially' URL encoded SVG as data URL works as expected in globals.css, e.g.

.red-bg {
  background-image: url("data:image/svg+xml,%3Csvg width='1' height='1' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='1' height='1' fill='red' /%3E%3C/svg%3E");
}

Using the same CSS in styled-jsx does not, e.g.

<style jsx>{`
  .red-bg {
    background-image: url("data:image/svg+xml,%3Csvg width='1' height='1' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='1' height='1' fill='red' /%3E%3C/svg%3E");
  }
`}</style>

What's worse is that declarations following the 'broken' declaration are not respected, e.g.

<style jsx>{`
  .red-bg {
    background-image: url("data:image/svg+xml,%3Csvg width='1' height='1' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='1' height='1' fill='red' /%3E%3C/svg%3E");
  }
  .pink-bg {
    background-color: pink; // not applied
  }
`}</style>

This worked without issue prior to updating to Next 14.2, but now is broken.

As a sanity check, I downgraded to Next 13 (13.5.6), and it does indeed work as expected:

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.1.0: Mon Oct  9 21:27:24 PDT 2023; root:xnu-10002.41.9~6/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 8
Binaries:
  Node: 20.11.1
  npm: 10.2.4
  Yarn: 1.22.19
  pnpm: 9.1.0
Relevant Packages:
  next: 14.2.3 // Latest available version is detected (14.2.3).
  eslint-config-next: N/A
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.4.5
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Not sure

Which stage(s) are affected? (Select all that apply)

next dev (local), Other (Deployed)

Additional context

No response

[olaj]

I have the same issue.

It seems to work in 14.1.4 but doesn't work in 14.2.0