Update @stylexjs/stylex to 0.13

.github/CODEOWNERS

@@ -1,2 +1 @@
 * @necolas
-/packages/scripts/* @necolas @nmn

apps/examples/postcss.config.js

@@ -8,7 +8,8 @@
 module.exports = {
   plugins: {
     'postcss-react-strict-dom': {
-      include: ['src/**/*.{js,jsx,mjs,ts,tsx}']
+      include: ['src/**/*.{js,jsx,mjs,ts,tsx}'],
+      useLayers: true
     },
     autoprefixer: {}
   }

apps/website/docs/api/02-css/03-defineConsts.md

@@ -0,0 +1,21 @@
+---
+draft: true
+---
+
+# css.defineConsts
+
+<p className="text-xl">How to define constants.</p>
+
+:::warning
+
+`css.defineConsts()` is currently only supported on web.
+
+:::
+
+## Overview
+
+...
+
+## API
+
+...

apps/website/docs/api/02-css/07-positionTry.md

@@ -0,0 +1,21 @@
+---
+draft: true
+---
+
+# css.positionTry
+
+<p className="text-xl">How to define position-try styles.</p>
+
+:::warning
+
+`css.positionTry()` is currently only supported on web.
+
+:::
+
+## Overview
+
+...
+
+## API
+
+...

apps/website/docs/api/index.md

@@ -15,9 +15,11 @@ sidebar_position: -1
 * [**css**](/api/css/) - An overview of working with styles.
 * [css.create](/api/css/create) - How to create styles.
 * [css.createTheme](/api/css/createTheme) - How to create themes.
+<!-- * [css.defineConsts](/api/css/defineConsts) - How to define constants. -->
 * [css.defineVars](/api/css/defineVars) - How to define variables.
 * [css.firstThatWorks](/api/css/firstThatWorks) - How to declare fallback values.
 <!-- * [css.keyframes](/api/css/keyframes) - How to declare animation keyframes. -->
+<!-- * [css.positionTry](/api/css/positionTry) - How to declare position-try styles. -->
 
 ## html