Helpers & utilities split (#28445)

site/content/docs/4.3/helpers/position.md

@@ -0,0 +1,33 @@
+---
+layout: docs
+title: Position
+description: Use these helpers for quickly configuring the position of an element.
+group: helpers
+toc: true
+---
+
+## Fixed top
+
+Position an element at the top of the viewport, from edge to edge. Be sure you understand the ramifications of fixed position in your project; you may need to add additional CSS.
+
+{{< highlight html >}}
+<div class="fixed-top">...</div>
+{{< /highlight >}}
+
+## Fixed bottom
+
+Position an element at the bottom of the viewport, from edge to edge. Be sure you understand the ramifications of fixed position in your project; you may need to add additional CSS.
+
+{{< highlight html >}}
+<div class="fixed-bottom">...</div>
+{{< /highlight >}}
+
+## Sticky top
+
+Position an element at the top of the viewport, from edge to edge, but only after you scroll past it. The `.sticky-top` utility uses CSS's `position: sticky`, which isn't fully supported in all browsers.
+
+**IE11 and IE10 will render `position: sticky` as `position: relative`.** As such, we wrap the styles in a `@supports` query, limiting the stickiness to only browsers that can render it properly.
+
+{{< highlight html >}}
+<div class="sticky-top">...</div>
+{{< /highlight >}}