Improve UI/UX Design

[mberrishdev]

Description

Enhance the visual design and user experience of the clipboard manager.

Tasks

• Redesign clipboard history card layout
• Improve color scheme and typography
• Add smooth animations/transitions
• Better empty state message
• Improve settings page layout
• Add dark/light mode toggle (not just transparency)
• Polish scrollbar styling

Design Goals

• Modern, minimal macOS aesthetic
• Better visual hierarchy
• Improved readability