Power Bi Themes

---
name: Power BI Themes
description: >
  Apply, inspect, and compare Power BI report themes and conditional formatting
  rules using pbi-cli. Invoke this skill whenever the user mentions "theme",
  "colours", "colors", "branding", "dark mode", "corporate theme", "styling",
  "conditional formatting", "colour scale", "gradient", "data bars",
  "background colour", "formatting rules", "visual formatting", or wants to
  change the overall look-and-feel of a report or apply data-driven formatting
  to specific visuals.
tools: pbi-cli
---

# Power BI Themes Skill

Manage report-wide themes and per-visual conditional formatting. No Power BI
Desktop connection is needed.

## Applying a Theme

Power BI themes are JSON files that define colours, fonts, and visual defaults
for the entire report. Apply one with:

```bash
pbi report set-theme --file corporate-theme.json
```

This copies the theme file into the report's `StaticResources/RegisteredResources/`
folder and updates `report.json` to reference it. The theme takes effect when
the report is opened in Power BI Desktop.

## Inspecting the Current Theme

```bash
pbi report get-theme
```

Returns:
- `base_theme` -- the built-in theme name (e.g. `"CY24SU06"`)
- `custom_theme` -- custom theme name if one is applied (or `null`)
- `theme_data` -- full JSON of the custom theme file (if it exists)

## Comparing Themes

Before applying a new theme, preview what would change:

```bash
pbi report diff-theme --file proposed-theme.json
```

Returns:
- `current` / `proposed` -- display names
- `added` -- keys in proposed but not current
- `removed` -- keys in current but not proposed
- `changed` -- keys present in both but with different values

This helps catch unintended colour changes before committing.

## Theme JSON Structure

A Power BI theme JSON file typically contains:

```json
{
  "name": "Corporate Brand",
  "dataColors": ["#0078D4", "#00BCF2", "#FFB900", "#D83B01", "#8661C5", "#00B294"],
  "background": "#FFFFFF",
  "foreground": "#252423",
  "tableAccent": "#0078D4",
  "visualStyles": { ... }
}
```

Key sections:
- `dataColors` -- palette for data series (6-12 colours recommended)
- `background` / `foreground` -- page and text defaults
- `tableAccent` -- header colour for tables and matrices
- `visualStyles` -- per-visual-type overrides (font sizes, padding, etc.)

See [Microsoft theme documentation](https://learn.microsoft.com/power-bi/create-reports/desktop-report-themes) for the full schema.

## Invalid Properties to Avoid

These properties look plausible but are **not in PBI's theme schema**. Including
them causes PBI Desktop to fail silently or crash when loading the report:

| Property | Location | Why invalid |
|---|---|---|
| `"radius": 8` | Inside `border` objects in `visualStyles` | Borders only accept `color` and `show` |
| `"page": { ... }` | Top-level key | Legacy pbiviz format — not valid in report themes |
| `"dropShadow": { "position": "Inner" }` | Inside `visualStyles` | No `position` sub-property exists for dropShadow |

**Safe top-level keys** for a custom theme:
`name`, `dataColors`, `background`, `foreground`, `tableAccent`,
`visualStyles`, `textClasses`, `outspaceColor`, `borderColor`, `shapeColors`

Always use `pbi report diff-theme` to preview changes before applying, and
open the report in Desktop once to confirm it loads before committing the file.

## Conditional Formatting

Apply data-driven formatting to individual visuals:

```bash
# Gradient background (colour scale from min to max)
pbi format background-gradient visual_abc --page page1 \
    --table Sales --column Revenue \
    --min-color "#FFFFFF" --max-color "#0078D4"

# Rules-based background (specific value triggers a colour)
pbi format background-conditional visual_abc --page page1 \
    --table Sales --column Status --value "Critical" --color "#FF0000"

# Measure-driven background (a DAX measure returns the colour)
pbi format background-measure visual_abc --page page1 \
    --table Sales --measure "Status Color"

# Inspect current formatting rules
pbi format get visual_abc --page page1

# Clear all formatting rules on a visual
pbi format clear visual_abc --page page1
```

## Workflow: Brand a Report

```bash
# 1. Create the theme file
cat > brand-theme.json << 'EOF'
{
  "name": "Acme Corp",
  "dataColors": ["#1B365D", "#5B8DB8", "#E87722", "#00A3E0", "#6D2077", "#43B02A"],
  "background": "#F8F8F8",
  "foreground": "#1B365D",
  "tableAccent": "#1B365D"
}
EOF

# 2. Preview the diff against the current theme
pbi report diff-theme --file brand-theme.json

# 3. Apply it
pbi report set-theme --file brand-theme.json

# 4. Verify
pbi report get-theme
```

## JSON Output

```bash
pbi --json report get-theme
pbi --json report diff-theme --file proposed.json
pbi --json format get vis1 --page p1
```