CSS Layout Debugger

Help me debug CSS layout issues on my web page.

**HTML structure:**
```html
{{HTML}}
```

**CSS styles:**
```css
{{CSS}}
```

**What I want the layout to look like:** {{DESIRED_LAYOUT}}
**What's actually happening:** {{ACTUAL_BEHAVIOR}}
**Browser(s) affected:** {{BROWSERS}}
**Viewport size:** {{VIEWPORT}}

Please provide:
1. **Layout Analysis**: Explain why the current layout behaves this way
2. **Box Model Check**: Verify padding, margin, and border calculations
3. **Flexbox/Grid Diagnosis**: Debug flex/grid container and item properties
4. **Positioning Issues**: Check positioning context and stacking
5. **Fixed CSS**: Provide corrected styles
6. **Cross-Browser Fixes**: Address browser-specific issues
7. **Responsive Considerations**: Ensure layout works across viewports
8. **DevTools Tips**: How to debug similar issues using browser DevTools