Grammar Fix

Grammar change it's to its

From:
"to make it back to it's (it is) correct size."
"to make it back to its correct size."

index.html

@@ -198,7 +198,7 @@
         Again, we use a `data-` attribute, this time it's `data-scale="4"`, so it means that this
         element will be 4 times larger than the others.
         From presentation and transitions point of view it means, that it will have to be scaled
-        down (4 times) to make it back to it's correct size.
+        down (4 times) to make it back to its correct size.
         
     -->
     <div id="title" class="step" data-x="0" data-y="0" data-scale="4">