Litefin is a high-performance, native Jellyfin media client designed specifically for Samsung Tizen and LG webOS smart TVs. It is built as a single-page web application using vanilla JavaScript with a custom component framework, no external UI libraries. The architecture is event-driven, centered around a global EventBus, StateManager, and Router. The application provides full media browsing, playback with advanced subtitle rendering (ASS/SSA via libass-wasm), live TV with EPG, SyncPlay group synchronization, a plugin system, and integration with Jellyseerr for media requests. It is optimized for TV remote control navigation with a sophisticated FocusManager and spatial navigation engine. The system communicates with a Jellyfin server via REST API and WebSocket for real-time events. It also integrates with TMDB (via Jellyseerr) for metadata and trailers, and uses a background service (Luna on WebOS, HTTP proxy on Tizen) for device discovery, Wake-on-LAN, and Smart Hub preview. The codebase is organized into core modules (App, Router, EventBus, StateManager), UI components (pages, modals, grids), a player subsystem with OSD menus, and platform adapters for Tizen and WebOS. It supports multiple build variants (Modern, Normal, Legacy, Ultra-Legacy) to accommodate different Chromium versions on TV firmware. Key entry points include src/index.js (bootstrap), src/core/App.js (orchestration), and src/core/Router.js (navigation). Data flows primarily through the ApiClient for Jellyfin endpoints and the WebSocketHandler for server push events. The plugin system allows third-party extensions like skip-intro and mdblist-ratings. The application is heavily optimized for TV hardware, using GPU-accelerated CSS transforms, lazy loading, and memory-efficient virtual scrolling.