CSS can be used not only for styling but also to add interactivity to UI components, reducing the reliance on JavaScript. By leveraging patterns such as the :target pseudo-class, developers can create interactive elements like modals or lightboxes, which change styles when targeted by a URL fragment. Radio buttons, with their ability to allow only one selection at a time, can be adapted to control components like tabs and accordions, enabling navigation with arrow keys. Additionally, the attr() CSS function can be used to create dynamic tooltips by fetching content from custom attributes in HTML. While CSS-based interactivity has limitations such as the inability to close dialogs with the escape key or dynamically load images, these methods can significantly reduce JavaScript dependencies, leading to more streamlined web applications.