nitpick phrasing

docs/components.html

@@ -1259,7 +1259,7 @@ lead: "Over a dozen reusable components built to provide iconography, dropdowns,
     <p>Since Bootstrap doesn't know how much space the content in your navbar needs, you might run into issues with content wrapping into a second row. To resolve this, you can:</p>
     <ol type="a">
       <li>Reduce the amount or width of navbar items.</li>
-      <li>Hide certain navbar items on certain screen sizes using <a href="../css/#responsive-utilities">responsive utility classes</a>.</li>
+      <li>Hide certain navbar items at certain screen sizes using <a href="../css/#responsive-utilities">responsive utility classes</a>.</li>
       <li>Change the point at which your navbar switches between collapsed and horizontal mode. Customize the <code>@grid-float-breakpoint</code> variable or add your own media query.</li>
     </ol>
   </div>