phsl / new-api

- Replace pink-purple gradient with indigo-purple gradient to match PersonalSetting.js color scheme
- Update icon container gradient from purple-indigo to indigo-purple for consistency
- Enhance shadow effects from shadow-sm to shadow-lg to align with card design standards
- Improve hover effects with refined opacity and smoother transitions (duration-300)
- Increase content background opacity from 70% to 80% for better readability
- Update scrollbar color to purple theme (rgba(139, 92, 246, 0.3))
- Standardize border radius to rounded-xl for unified styling
- Apply consistent styling to "thinking in progress" state with matching gradient background

This change ensures visual consistency across the application by adopting the same
purple-blue color palette used in PersonalSetting component, creating a more
cohesive user experience.