## MODIFIED Requirements

### Requirement: Layout Component
The system SHALL provide a consistent application layout for authenticated screens across desktop and mobile sizes.

#### Scenario: Application shell
- **GIVEN** the frontend application
- **THEN** a Layout component SHALL:
  - Display a header with user info and logout
  - Display sidebar navigation on desktop (width >= 768px)
  - Show main content area
  - Collapse sidebar into a mobile menu toggle on small viewports
  - **MODIFIED**: Display a bottom tab bar on mobile (width < 768px) with tabs for Home, Projects, Sessions, Tools, Settings
  - **MODIFIED**: Hide sidebar navigation on mobile viewports

#### Scenario: Navigation links
- **GIVEN** the sidebar navigation
- **THEN** it SHALL include links to:
  - Dashboard
  - Projects
  - Repositories
  - SSH Keys
  - Settings
- **MODIFIED**: The bottom tab bar SHALL include tabs for:
  - Home (Dashboard)
  - Projects
  - Sessions
  - Tools (Tool Workshop)
  - Settings

### Requirement: Responsive Design
The system SHALL support mobile devices.

#### Scenario: Mobile viewport
- **GIVEN** a mobile device
- **WHEN** the app loads
- **THEN**:
  - **MODIFIED**: A bottom tab bar is displayed for primary navigation
  - Content adapts to screen width
  - Touch targets are appropriately sized (minimum 44px)
  - **ADDED**: All multi-column layouts stack vertically
  - **ADDED**: Dialogs fit within the viewport and are scrollable
  - **ADDED**: Page headers include back buttons where applicable
