# Global Colour Variable Ghost — divi/post-content Module

**Discovered**: 2026-08-07 on l8.kaburu.co.uk (session 20260807_074844_fe5793bb)

## Symptom

A grey/white background band appears behind page content that **survives template recreation**. The Visual Builder shows the colour picker as "set" (chip displays `$variable(...gcid-body-color...)`) but the user cannot change it — the colour reappears after save.

## Root Cause

The `divi/post-content` module (the template wrapper that renders page content) carries a background attribute with a **global colour variable**:

```json
"background": {
  "color": "$variable(...gcid-body-color...)"
}
```

This resolves at render time to the theme's body text colour (light grey/white). When the user tries to change it in the VB, their selection writes `rgba(73, 10, 10, 0)` — red at 0% opacity — which is invisible. The "save" appears to fail because the new value is transparent.

## Fix

1. Identify the post-content module: `diviops_page_get_layout` → look for `block_name: "divi/post-content"` with `auto_index: "post-content:1"`
2. Clear the background:
   ```bash
   diviops_module_update \
     page_id=<TB_LAYOUT_ID> \
     auto_index="post-content:1" \
     "module.decoration.background.desktop.value.color"="rgba(0,0,0,0)"
   ```
3. Flush cache: `diviops_meta_flush_cache post_id=<TB_LAYOUT_ID>`
4. Verify served CSS:
   ```bash
   curl -sL https://site.com/page | grep -o 'background-color:rgba(0,0,0,0)'
   ```

## Why This Is Insidious

- The ghost lives in the **template's post-content module**, not the page content itself
- Template recreation from a clean blueprint **does not fix it** — the post-content module is part of the TB structure
- The VB shows a colour chip (not a picker), so the user thinks they're editing a colour when they're actually editing a variable reference
- Zero-value opacity (`rgba(..., 0)`) is invisible — appears as "doesn't save"

## Prevention

When building TB templates via API:
- Explicitly set `module.decoration.background.desktop.value.color` to a solid value or `rgba(0,0,0,0)` on the post-content module
- Never leave it as a variable reference unless intentionally designing with global colours

## Related

- Pitfall #36 in divi-5-builder skill
- Session 20260807_074844_fe5793bb — "THE GHOST" discovery