feat(free-demo): beautify zoom tool style

apps/demo-free-layout/src/components/tools/styles.tsx

@@ -27,11 +27,12 @@ export const ToolSection = styled.div`
 `;
 
 export const SelectZoom = styled.span`
-  padding: 2px;
+  padding: 4px;
   border-radius: 8px;
   border: 1px solid rgba(68, 83, 130, 0.25);
   font-size: 12px;
   width: 50px;
+  cursor: pointer;
 `;
 
 export const MinimapContainer = styled.div`