fix styles

Author: danielang

src/components/style.js

@@ -41,11 +41,12 @@ export default StyleSheet.create({
     width: STEP_NUMBER_DIAMETER,
     height: STEP_NUMBER_DIAMETER,
     overflow: 'hidden',
-    alignItems: 'center',
-    justifyContent: 'center',
     zIndex: ZINDEX + 1,
   },
   stepNumber: {
+    flex: 1,
+    alignItems: 'center',
+    justifyContent: 'center',
     borderWidth: 2,
     borderRadius: STEP_NUMBER_RADIUS,
     borderColor: '#FFFFFF',