fix(levels): match top/bottom margins to left padding on kyu detail boxes

- Reduced my (vertical margins) from '6' to '2' to match pl (left padding)
- Ensures consistent spacing on all sides of the detail box grid

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/app/levels/page.tsx

@@ -695,7 +695,7 @@ export default function LevelsPage() {
                           borderColor: 'gray.600',
                           maxW: '480px',
                           alignContent: 'center',
-                          my: '6',
+                          my: '2',
                         })}
                       >
                         {sections.map((section, idx) => {