Yoga Docs: Rename website-next to website (#1613)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1613

So that GitHub links to edit a page point to the right place.

This will fail in OSS build until I switch the directory used by Vercel instance, but I am waiting to do that until ready to land, since that would cause other in progress changes to fail when exported.

Reviewed By: joevilches

Differential Revision: D54837857

website/docs/styling/index.md

@@ -0,0 +1,47 @@
+---
+sidebar_position: 2
+---
+
+# Styling
+
+Each Yoga node has an associated style. Nodes may be styled using similar properties to CSS, with some caveats.
+
+## Default styles
+
+The default Yoga node style is similar to a box on web set to `display: flex`, with a few notable exceptions:
+
+1. `flex-direction` defaults to `column` instead of `row`
+2. `align-content` defaults to `flex-start` instead of `stretch`
+3. `flex-shrink` defaults to `0` instead of `1`
+4. `position` defaults to `relative` instead of `static`
+
+Yoga may be [configured](../getting-started/configuring-yoga.mdx) to align to the defaults on web for `flex-direction`, `align-content`, and `flex-shrink` by setting the `UseWebDefaults` flag.
+
+:::warning
+
+Because `UseWebDefaults` was established before the introduction of `position: 'static'`, it does not change the default `position`, in order to preserve compatibility.
+
+:::
+
+## Box Sizing
+
+Yoga acts as if [`box-sizing: 'border-box'`](https://developer.mozilla.org/en-US/docs/Web/CSS/box-sizing) is set. This means that specified dimensions for a box will include the space taken for padding and border.
+
+## Edges
+
+Margin, padding, position, and border, are set against an Edge, which may be:
+1. Relative to writing direction (start/end)
+2. A physical edge (top/right/left/bottom)
+3. A collection of edges (vertical/horizontal/all)
+
+A style value may be set against multiple Edge values at once, with precedence given in the above order.
+
+## Units
+
+Yoga does not operate on CSS units like `px` or `em`. Yoga instead works on "points", representing an arbitrary, canonical absolute unit (usually mapped to display independent pixels), along with percentage. Other units should be absolutized before being given to Yoga.
+
+## Non-standard properties
+
+Yoga's `aspect-ratio` property was added before the same property was added to CSS, and may act subtlety different. These differences may be reconciled in a future version of Yoga.
+
+Yoga's `flex` shorthand will act as `flex-grow` if positive, or `flex-shrink` if negative.