Are the recommended PC specifications available?
No. Steam currently marks the recommended specification as TBD.
Confirmed explanation
The published hardware is only the minimum estimate for upscaled 1080p, 30fps and Low settings. It should not be relabeled as a recommended 60fps or high-settings build.
What is not confirmed yet
Official 60fps, 1440p, 4K and maximum-setting targets remain unannounced.