move responsive embed to utilities docs, update the nav to dedupe things

1 files changed, 28 insertions, 0 deletions

diff --git a/docs/components/utilities.md b/docs/components/utilities.md
index 0d6fe2595..78ee54f82 100644
--- a/docs/components/utilities.md
+++ b/docs/components/utilities.md
@@ -221,3 +221,31 @@ Utilize the `.text-hide` class or mixin to help replace an element's text conten
   @include text-hide;
 }
 {% endhighlight %}
+
+### Responsive embeds
+
+Allow browsers to determine video or slideshow dimensions based on the width of their containing block by creating an intrinsic ratio that will properly scale on any device.
+
+Rules are directly applied to `<iframe>`, `<embed>`, `<video>`, and `<object>` elements; optionally use an explicit descendant class `.embed-responsive-item` when you want to match the styling for other attributes.
+
+**Pro-Tip!** You don't need to include `frameborder="0"` in your `<iframe>`s as we override that for you.
+
+{% example html %}
+<div class="embed-responsive embed-responsive-16by9">
+  <iframe class="embed-responsive-item" src="//www.youtube.com/embed/zpOULjyy-n8?rel=0" allowfullscreen></iframe>
+</div>
+{% endexample %}
+
+Aspect ratios can be customized. There are two available in Bootstrap, 16x9 and 4x3 (two of the most common for video).
+
+{% highlight html %}
+<!-- 16:9 aspect ratio -->
+<div class="embed-responsive embed-responsive-16by9">
+  <iframe class="embed-responsive-item" src="..."></iframe>
+</div>
+
+<!-- 4:3 aspect ratio -->
+<div class="embed-responsive embed-responsive-4by3">
+  <iframe class="embed-responsive-item" src="..."></iframe>
+</div>
+{% endhighlight %}