diff --git a/src/ViewerNav.tsx b/src/ViewerNav.tsx
index 420be48..eb174d3 100644
--- a/src/ViewerNav.tsx
+++ b/src/ViewerNav.tsx
@@ -21,9 +21,10 @@ export default class ViewerNav extends React.Component<ViewerNavProps, any> {
   }
 
   render() {
-    let marginLeft = (Math.ceil(this.props.images.length / 2) - this.props.activeIndex - 1) * 1.5 * 30;
+    var marginLeft = `calc(50% - ${this.props.activeIndex + 1} * 31px)`;
     let listStyle = {
-      marginLeft: `${marginLeft}px`,
+      marginLeft: marginLeft,
+			textAlign: 'left'
     };
 
     return (