## 1. Implementation

- [x] 1.1 In `themeunit.pas`, add `ApplyModernScrollBarStylesheet` helper and call it for scrollable controls in `DoApplyTheme`.
- [x] 1.2 Ensure dynamically created `TScrollBox` controls in tab units receive the modern scrollbar styling.

## 2. Verification

- [x] 2.1 Compile project with `lazbuild goverlay.lpi` and verify visual scrollbars.
