You can style Qt Quick Controls, which are the QtWidgets equivalent objects in QML.<p><a href="http:&#x2F;&#x2F;doc.qt.io&#x2F;qt-5&#x2F;qtquickcontrolsstyles-index.html" rel="nofollow">http:&#x2F;&#x2F;doc.qt.io&#x2F;qt-5&#x2F;qtquickcontrolsstyles-index.html</a><p>This is how many new apps are coming out using QML and doing their own custom UI theming rather than doing system default. It also beats the hell out of CSS by using the same object model relationships you are already using when laying out QML objects.<p>Yes, if you use language primitives like rect&#x27;s and text&#x27;s then you have to create either your own theming engine template classes and then use those, or manually manage all the styling per object. But then you are doing it wrong if your project does not warrant that kind of ground up custom craftsmanship.