Accessible Navigation Patterns

I need to implement accessible navigation components.

**Components Needed:**
- Main navigation: [horizontal/vertical/mega menu]
- Mobile menu: [slide-out/dropdown/full-screen]
- Breadcrumbs: [yes/no]
- Skip links: [yes/no]
- Side navigation: [yes/no]

**Design Requirements:**
[Describe visual design and behavior]

**Current Navigation:**
```jsx
[paste current navigation code]
```

**Accessibility Requirements:**
- WCAG level: [AA/AAA]
- Screen readers tested: [list]
- Keyboard navigation: [full required]

Please provide:
1. Accessible main navigation
2. Mobile menu implementation
3. Keyboard navigation patterns
4. ARIA attributes and roles
5. Focus management
6. Screen reader announcements
7. Skip link implementation