SGR 2 (Faint/Dim) is ineffective on light themes

[xj-ms]

Windows Terminal version

No response

Windows build number

No response

Other Software

No response

Steps to reproduce

1. Configure Powershell to use a light theme (e.g. One Half Light)
2. Run

Write-Host "`e[2mDim text`e[0m vs Normal text"

Expected Behavior

No response

Actual Behavior

On light themes, dim text is visually identical to normal text. There is no perceptible difference.

On dark themes, dim works as expected (text becomes visibly darker).

[xj-ms]

The existing dimming logic always halves the foreground color:

fg = (fg >> 1) & 0x7F7F7F; // Divide foreground color components by two.

We can blend it with the background instead