fix(opencre): improve scrollbar styling and remove visible track background

[ParthAggarwal16]

Summary

This PR improves the visual appearance of the site scrollbar by removing the visible white scrollbar track and styling the scrollbar thumb to better match the UI.

Currently, the scrollbar track appears as a white background which creates a visible rectangle when scrolling. This PR updates the styling so the track blends with the page background and only the scrollbar thumb is visible.

Changes

Modified :

application/frontend/src/styles/app.scss

Key updates:

• Set scrollbar track background to transparent
• Styled scrollbar thumb with rounded edges
• Adjusted thumb appearance for a cleaner UI

Result

• Scrollbar background no longer appears as a white rectangle
• Thumb appears as a minimal rounded “bean-like” indicator
• Visual consistency with the page background

closes #787

Screen rocording :

scrollbar.Screen.Recording.2026-03-05.at.11.44.54.PM.mov

[ParthAggarwal16]

with the commit f7781f5
Now, the scrollbar should also be transparent even when hovering