Reinstate box shadow for HideSplitViewButton

Maintain focusVisible styling as an override.

Author: microbit-robert

src/common/SplitView/HideSplitViewButton.tsx

@@ -82,6 +82,9 @@ const HideSplitViewButton = React.forwardRef(
             // ghost-over-gray values).
             _hover: { background: "gray.100" },
             _active: { background: "gray.200" },
+            // Likewise a flat boxShadow from a call site (e.g. Simulator's
+            // md shadow) beats the recipe-layer focus ring — restate it.
+            _focusVisible: { focusShadow: "outline" },
             color: "brand.500",
             zIndex: "splitViewHideButton",
             ...cssProp,

src/simulator/Simulator.tsx

@@ -110,6 +110,7 @@ const Simulator = ({
             onClick={onSimulatorHide}
             splitViewShown={shown}
             direction="expandLeft"
+            css={{ boxShadow: "md" }}
           />
         </Flex>
         <VStack gap="5" bg="gray.75" ref={simControlsRef}>