UI Improvements

Simplified Thinking Indicator

The thinking indicator display has been simplified:

Before:

• Used a bordered box with single-line border on the left
• Complex padding and margin configuration
• Multiple style properties for the border

After:

• Simple indentation using paddingLeft: 2
• Cleaner, more minimal appearance
• Removed the border styling entirely

This change makes the thinking indicator less visually intrusive while maintaining clarity.