Fix typo w-20 -> w-10

Author: mrmrs

index.html

@@ -612,7 +612,7 @@ <h3 class="f6 ttu fw6 mt0 bb pb2">Grids</h3>
             <div class="outline bg-white tc pv4"><code>fl w-20 pa2</code></div>
           </div>
           <div class="fl w-10 pa2">
-            <div class="outline bg-white tc pv4"><code>fl w-20 pa2</code></div>
+            <div class="outline bg-white tc pv4"><code>fl w-10 pa2</code></div>
           </div>
           <div class="fl w-10 pa2">
             <div class="outline bg-white tc pv4"><code>fl w-10 pa2</code></div>