kvantum

Kvantum is a free and open-source theme engine for the Qt application framework. It provides an alternative styling system that renders Qt widgets with scalable, vector-based graphics, enabling high-quality and cohesive appearances across Qt-based applications.

Developed as a community project, Kvantum aims to improve the visual quality and consistency of Qt interfaces beyond what standard Qt styles offer. It is commonly used with KDE Plasma and LXQt environments, and is available on many Linux distributions through official repositories. The project supports both Qt 5 and Qt 6, with themes and configurations that can be shared among users.

Kvantum runs as a Qt style plugin. Users install Kvantum along with one or more Kvantum themes, and then use Kvantum Manager to activate and customize themes. The manager exposes options for color palettes, fonts, icon sizes, radii, and other style parameters. Themes can be exported or bundled, enabling easy sharing of visual configurations. When Kvantum is selected as the platform theme, applicable Qt applications adopt the configured appearance automatically.

Kvantum themes are distributed as packages or theme files and are contributed by the community. The project emphasizes accessibility and customization, providing a flexible path to consistent, modern visuals for Qt-based software.