This patch introduces a new styling API for Controls called StyleKit. StyleKit provides a higher-level, key–value–based approach to styling applications, serving as an alternative to working directly with the lower-level Templates API. The primary goal of StyleKit is to offer a unified API for styling both Controls and Widgets. The current Templates-based approach relies heavily on JavaScript, which makes it unsuitable for use with Widgets. This initial version supports Controls only; support for Widgets will be added in a future update. StyleKit is designed to make it easier for designers and UI developers to: - Focus on visual styling rather than Template logic (such as geometry, delegate positioning, and handle placement). - Allow style properties to propagate, enabling you to factor out common styling into shared control types and override only what differs in the more specific control types. - Style controls independently in each of their states, without needing nested ternary expressions to check state. - Define and apply multiple themes with minimal effort. - Provide different style variations depending on context. For example, styling a Switch differently when it appears inside a ToolBar. [ChangeLog][Qt labs] Introduced new QML module 'StyleKit'. StyleKit provides a flexible styling framework for Qt Quick Controls, enabling developers to define reusable styles and themes using a simple key-value property format. Change-Id: Iae25324486aea7a7b9b2ce52135327ec7e9b6f59 Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>