This patch enhances accessibility by introducing high-contrast visual cues across various controls when high-contrast mode is preferred. Previously, controls in the Basic style did not provide sufficient visual distinction in high-contrast mode. This patch adds a visible contour (border) around controls when high-contrast mode is enabled. For some controls, the contour is added by adjusting the border color and width. For others (e.g., highlighted ComboBox items), a Rectangle is drawn around the control. TextArea and Tumbler controls are also updated accordingly. Separator controls now increase their width or height based on orientation in high-contrast mode for better visibility. ScrollBar and ScrollIndicator controls: - Previously, these controls relied solely on handle color changes, which were insufficient in high-contrast mode. - This patch introduces an optional background and increases the handle's contrast to improve visibility. The patch also ensures that text and border colors adapt to the high-contrast palette, improving legibility and focus indication throughout the controls. Minor adjustments to Menu, Delegate, and Header controls for consistent high-contrast appearance. Task-number: QTBUG-135687 Pick-to: 6.10 Change-Id: I460bd6fa2e48a47f20c2ba053ab453f32de18add Reviewed-by: Oliver Eftevaag <oliver.eftevaag@qt.io>