# Mobile Bottom Tab Bar Verification (bf-om23)

## Finding

The mobile bottom tab bar specified in §16.4 **IS implemented**, but its styles are located in `web/index.html` as inline styles rather than in the external CSS files (`base.css`, `mobile.css`, `components.css`).

## Implementation Location

**HTML Structure** (`web/index.html` lines 898-918):
```html
<!-- Mobile bottom tab bar -->
<div class="mobile-bottom-nav">
  <div class="nav-links">
    <a href="#/" class="nav-link">
      <span>🏠</span>
      <span>Home</span>
    </a>
    <a href="#/watch" class="nav-link">
      <span>👀</span>
      <span>Watch</span>
    </a>
    <a href="#/compete" class="nav-link">
      <span>⚔️</span>
      <span>Compete</span>
    </a>
    <a href="#/leaderboard" class="nav-link">
      <span>🏆</span>
      <span>Board</span>
    </a>
  </div>
</div>
```

**CSS Styles** (`web/index.html` lines 158-182, 229-236):
```css
/* Mobile bottom tab bar */
.mobile-bottom-nav {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 8px 0;
  z-index: 100;
}

.mobile-bottom-nav .nav-links {
  justify-content: space-around;
  width: 100%;
}

.mobile-bottom-nav .nav-link {
  flex-direction: column;
  padding: 6px 12px;
  font-size: 0.75rem;
  text-align: center;
}

/* Responsive */
@media (max-width: 639px) {
  /* Show bottom tab bar */
  .mobile-bottom-nav {
    display: block;
  }

  /* Add padding to bottom of main content for bottom nav */
  #app {
    padding-bottom: 70px;
  }
}
```

## External CSS References

The external CSS files reference `.mobile-bottom-nav` but do NOT define its styles:

- **`mobile.css` line 616**: Hides `.mobile-bottom-nav` on desktop (>1024px)
- **`mobile.css` line 711-718**: Minimal padding adjustments in landscape mode
- **`mobile.css` line 6**: Comment mentioning "bottom tab bar"

## Specification Compliance

The implementation matches §16.4 of the plan:
- Four bottom tabs: Home, Watch, Compete, Board
- Persistent bottom tab bar on mobile (<640px)
- Thumb-reachable, always visible
- Hidden on desktop/tablet
- Proper z-index layering (z-index: 100)

## Conclusion

**Status**: The mobile bottom tab bar is fully implemented and functional. The styles are inline in `index.html` rather than in external CSS files, which is a valid (though less modular) approach.

**Recommendation**: If desired for better code organization, the inline styles could be moved to `mobile.css`, but this is not necessary for functionality.