Rearrange all the docs to allow for a docs/major.minor/ setup

docs/4.0/utilities/visibility.md

@@ -0,0 +1,33 @@
+---
+layout: docs
+title: Visibility
+description: Control the visibility, without modifying the display, of elements with visibility utilities.
+group: utilities
+---
+
+Set the `visibility` of elements with our visibility utilities. These do not modify the `display` value at all and are helpful for hiding content from most users, but still keeping them for screen readers.
+
+Apply `.visible` or `.invisible` as needed.
+
+{% highlight html %}
+<div class="visible">...</div>
+<div class="invisible">...</div>
+{% endhighlight %}
+
+{% highlight scss %}
+// Class
+.visible {
+  visibility: visible;
+}
+.invisible {
+  visibility: hidden;
+}
+
+// Usage as a mixin
+.element {
+  @include invisible(visible);
+}
+.element {
+  @include invisible(hidden);
+}
+{% endhighlight %}