[Bug] Placeholder text and UI elements render in white instead of gray on macOS with dark terminal background (tmux + truecolor)

### Describe the bug

**Version**: 1.0.10
**OS**: macOS 15.5
**Terminal**: Alacritty (and reproduced on macOS default terminal)
**Shell**: zsh
**TERM**: tmux-256color (and reproduced with TERM=xterm-256color)
**COLORTERM**: truecolor
**Theme tried**: default, high-contrast
**Symptoms**: Placeholder text renders as full white instead of gray; no visible difference between color modes

Expected:

Actual:

### Affected version

1.0.10

### Steps to reproduce the behavior

_No response_

### Expected behavior

I expect that placeholder, and other options are gray instead of fully white.

### Additional context

_No response_