* Refactor CSS styles: replace hardcoded colors with CSS variables for accent colors and optimize spacing rules in layout files.
* Update CSS styles: streamline selectors, enhance hover effects, and adjust focus states for chat components and layout elements.
* Enhance focus styles for chat components: update border colors and box-shadow effects for improved accessibility and visual consistency.
* Implement theme management in UI: add dynamic theme switching based on user settings, update CSS variables for new themes, and enhance security by preventing prototype pollution in form utilities.
* Implement border radius customization in UI: add settings for corner roundness, update CSS styles for sliders, and integrate border radius adjustments across components.
* Remove border radius property from UI settings and related functions to simplify configuration and enhance consistency across components.
* Enhance responsive design in UI: add media queries for mobile layouts, adjust padding and grid structures, and implement bottom navigation for improved usability on smaller screens.
* UI: add corner radius slider to Appearance settings