---
id: TASK-033
title: 'TUI: Auto-select dark/light theme based on macOS appearance'
status: To Do
assignee: []
created_date: '2026-06-12 04:21'
labels:
  - tui
  - enhancement
dependencies:
  - TASK-021
priority: low
ordinal: 33000
---

## Description

<!-- SECTION:DESCRIPTION:BEGIN -->
On startup, detect macOS Dark Mode and choose the matching theme variant automatically, rather than always defaulting to `flexoki`.

Detection:
```python
import subprocess
result = subprocess.run(
    ["defaults", "read", "-g", "AppleInterfaceStyle"],
    capture_output=True, text=True
)
is_dark = result.returncode == 0 and "Dark" in result.stdout
```

Startup behavior:
- If state file (TASK-021) has a saved theme: use it as-is (user explicitly chose it)
- If no saved theme: pick `flexoki-dark` when Dark Mode is on, `flexoki` when off
- `t` cycling still works normally and saves to state file
- A `--no-auto-theme` CLI flag or constant at top of file disables this behavior
<!-- SECTION:DESCRIPTION:END -->

## Acceptance Criteria
<!-- AC:BEGIN -->
- [ ] #1 First launch with no saved theme picks dark variant in Dark Mode, light variant otherwise
- [ ] #2 Saved theme from state file takes priority over auto-detection
- [ ] #3 Detection failure (non-macOS, permission error) falls back to flexoki silently
- [ ] #4 Auto-detection runs synchronously before the app loop starts (no flash of wrong theme)
<!-- AC:END -->