Color Theory for Data Visualization

Help me develop an optimal color strategy for my data visualization project:

Visualization Context:
- Chart types: [list all charts in project]
- Number of categories: [max categories to distinguish]
- Data nature: [sequential/diverging/categorical]
- Emotional tone: [professional/urgent/friendly]

Current Situation:
- Brand colors available: [list hex codes]
- Existing palette issues: [describe problems]
- Printing requirements: [color/B&W]

Requirements Analysis:

1. Categorical Palette
   - Number of distinct colors needed
   - Must-use brand colors
   - Colors to avoid

2. Sequential Palette
   - Low to high value representation
   - Number of steps needed
   - Single hue or multi-hue

3. Diverging Palette
   - Neutral point meaning
   - Positive/negative representation
   - Critical threshold highlighting

4. Semantic Colors
   - Status indicators (good/warning/bad)
   - Trend direction colors
   - Highlight and selection states

Accessibility Requirements:
- Color blindness consideration: [types to support]
- Contrast ratios needed
- Pattern alternatives

Please provide:
- Complete palette with hex codes
- Usage guidelines
- Accessibility validation
- Tool-specific implementation (Tableau/Power BI/CSS)