## Why
The site currently uses Bootstrap 5.3.2 from CDN with default styling. To establish a unique visual identity and brand consistency, we need the ability to customize Bootstrap variables (font sizes, colors, spacing) and add custom styles without modifying the core framework.

## What Changes
- Add Hugo SCSS/SASS processing pipeline using Hugo Pipes
- Create custom SCSS file structure for Bootstrap variable overrides and custom styles
- Maintain Bootstrap CSS from CDN for core framework
- Compile custom styles to supplement Bootstrap defaults
- Enable customization of heading font sizes, link colors, and other design tokens

## Impact
- Affected specs: `styling` (new capability)
- Affected code:
  - `layouts/_default/baseof.html` - Update to include compiled custom CSS
  - `assets/scss/` - New directory for SCSS files
  - `hugo.toml` - May need configuration for SCSS processing
- No breaking changes to existing functionality
- Performance: Minimal impact, adds one additional CSS file (~few KB)