slightly clarify button.active use in docs

css.html

@@ -2116,7 +2116,7 @@ For example, <code>&lt;section&gt;</code> should be wrapped as inline.
     <p>Buttons will appear pressed (with a darker background, darker border, and inset shadow) when active. For <code>&lt;button&gt;</code> elements, this is done via <code>:active</code>. For <code>&lt;a&gt;</code> elements, it's done with <code>.active</code>. However, you may use <code>.active</code> <code>&lt;button&gt;</code>s should you need to replicate the active state progammatically.</p>
 
     <h3>Button element</h3>
-    <p>No need to add <code>:active</code> as it's a pseudo state, but if you need it, go ahead and add <code>.active</code>.</p>
+    <p>No need to add <code>:active</code> as it's a pseudo state, but if you need to force it, go ahead and add <code>.active</code>.</p>
     <p class="bs-example">
       <button type="button" class="btn btn-primary btn-lg active">Primary button</button>
       <button type="button" class="btn btn-default btn-lg active">Button</button>