Kvantum is a Qt-based SVG theme engine for Linux desktop environments, implemented as a QStyle plugin that renders widgets using vector graphics from theme configuration files. The system includes a style plugin (Kvantum style), a GUI manager (Kvantum Manager) for installing, selecting, and configuring themes, and a preview application (Kvantum Preview) to showcase widget rendering. The style engine supports complex theming with configurable frame, interior, indicator, label, and size specs, as well as animations, blur effects, window dragging, per-application hacks, and desktop environment integration (KDE, LXQt, GNOME, etc.). The architecture is a monolith in the sense that the style plugin and two companion apps share common code paths (e.g., ThemeConfig, BlurHelper, WindowManager), but the codebase is split across Qt4, Qt5, and Qt6 variants with significant duplication. The primary data flow is: user selects a theme → Kvantum Manager writes config files → Kvantum style reads .kvconfig and .svg assets at runtime → Qt applications render widgets according to the theme specifications. External dependencies are Qt (≥6.6), QSvgRenderer, and optionally KDE's KWindowEffects for blur.