Spatialized html with z=0 gets covered by parent traditional html

[ZincR]

Duplicate check

• I searched existing issues and discussions

Steps to reproduce

  <div>
    {/* Shows a spatialized HTML plane using a system background material. */}
    <span
      className="api-plane"
      style={{
        position: 'absolute',
        '--xr-background-material': 'translucent',
      }}
      enable-xr
    ></span>
  </div>

Expected vs Actual Behavior

Expected a translucent span nested within larger div, but outer div wins z-fighting and child span is not displayed.

Dev Environment

• Run Target (Vision Pro / Simulator / Browser): Simulator/Browser
• OS: Any
• Node.js version: Any
• WebSpatial & Vite versions: Any