Added search operators on mobile with wrapping chips that can be tapped to remove them, and a full-width picker above the keyboard. Wrapping chips work across all screen sizes, with visual feedback and touch-friendly interaction. Fixed a bug where the not-found page had unreadable text in Graphite and AMOLED themes (white text on white background). All four themes now display text correctly on the 404 page, with appropriate readability in high-contrast and dark mode variants.