(docs) Fix RGBA value

README.md

@@ -50,7 +50,7 @@ bower install baguettebox.js --save
   https://cdnjs.com/libraries/baguettebox.js
 
   http://jsdelivr.com/projects/baguettebox.js
-  
+
 3. Copy URLs of the latest version (both `.js` and `.css` files)
 
 2. Paste the URLs in your HTML file:
@@ -119,7 +119,7 @@ The following options are available:
 | `afterShow` | `function` | `null` | Callback to be run after showing the overlay |
 | `afterHide` | `function` | `null` | Callback to be run after hiding the overlay |
 | `onChange` | `function(currentIndex, imagesCount)` | `null` | Callback to be run when image changes |
-| `overlayBackgroundColor` | `String` | `'rgba`<br>`(0,0,0.8)'` | Background color for the lightbox overlay |
+| `overlayBackgroundColor` | `String` | `'rgba`<br>`(0,0,0,0.8)'` | Background color for the lightbox overlay |
 | `filter` | `RegExp` | `/.+\.(gif|jpe?g|png|webp)/i` | Pattern to match image files. Applied to the `a.href` attribute |
 
 ## API