docs: Implemented "recipe" page (#791)

* Implemented recipe page with examples of common styling patterns

apps/docs/docs/learn/06-recipes/01-contextual-styles.mdx

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+---
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+sidebar_position: 6
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# Conditional styles based on context
+
+StyleX lets you apply styles conditionally. Any condition can be used to do so, `Props`, `State` or `Context`. 
+
+The React Context API (and other similar APIs) can be used to avoid prop-drilling
+and provide conditions that child component can read and apply styles conditionally.
+
+Context can help reduce prop-drilling by sharing state across components. This can often
+an alternative to using descendent selectors where the same results can be achieved
+*without* "styling at a distance".
+
+For example, you can manage the open or closed state of a sidebar using React Context
+and conditionally apply styles:
+
+## Defining context and styles
+
+This file sets up the `SidebarContext` and defines the styles for the sidebar in one place.
+The context provides a way to share the open/closed state, and the styles determine
+the appearance of the sidebar based on that state.
+
+```tsx
+import { createContext } from 'react';
+import * as stylex from '@stylexjs/stylex';
+
+export default createContext(false);
+```
+## Building the sidebar component
+The `Sidebar` component uses the `SidebarContext` to determine its open or closed state
+and conditionally applies the appropriate styles.
+
+```tsx
+import React, { useContext } from 'react';
+import * as stylex from '@stylexjs/stylex';
+import { SidebarContext } from './SidebarContext';
+
+export default function Sidebar({ children }) {
+  const isOpen = useContext(SidebarContext);
+
+  return (
+    <div {...stylex.props(styles.base, isOpen ? styles.open : styles.closed)}>
+      {children}
+    </div>
+  );
+}
+
+const styles = stylex.create({
+  base: {...},
+  open: {
+    width: 250,
+  },
+  closed: {
+    width: 50,
+  },
+});
+```
+
+## Using the sidebar in a parent component
+
+The `App` component manages the sidebar's open/closed state and provides it to
+ child components through `SidebarContext.Provider`. A button toggles the sidebar state dynamically.
+
+```tsx
+import React, { useState } from 'react';
+import SidebarContext from './SidebarContext';
+import Sidebar from './Sidebar';
+
+export default function App() {
+  const [isSidebarOpen, setIsSidebarOpen] = useState(false);
+
+  return (
+    <SidebarContext.Provider value={isSidebarOpen}>
+      <button onClick={() => setIsSidebarOpen(!isSidebarOpen)}>
+        Toggle Sidebar
+      </button>
+      <Sidebar>
+        <p>Sidebar Content</p>
+      </Sidebar>
+    </SidebarContext.Provider>
+  );
+}
+```
+

apps/docs/docs/learn/06-recipes/02-variants.mdx

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+---
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+sidebar_position: 5
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# Variants
+
+The "variants" pattern allows you to conditionally apply one of several predefined styles based on a value. This is especially useful for theming or dynamic component behavior.
+
+### Example: Button Variants
+
+Here’s how you can create a button component with different visual styles based on a `variant` prop:
+
+```tsx
+import * as stylex from '@stylexjs/stylex';
+
+const styles = stylex.create({
+  base: {
+    appearance: 'none',
+    borderWidth: 0,
+  },
+});
+const variants = stylex.create({
+  primary: {
+    backgroundColor: {
+      default: 'blue',
+      ':hover': 'darkblue',
+    },
+    color: 'white',
+  },
+  secondary: {
+    backgroundColor: {
+      default: 'gray',
+      ':hover': 'darkgray',
+    },
+    color: 'white',
+  },
+});
+function Button({ variant = 'primary', ...props }) {
+  return <button {...props} {...stylex.props(styles.base, variants[variant], props.style)} />;
+}
+
+// Usage
+<Button variant="primary">Primary</Button>
+<Button variant="secondary">Secondary</Button>
+```

apps/docs/docs/learn/06-recipes/03-descendant styles.mdx

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+---
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+sidebar_position: 7
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# Descendant styles dependent on ancestor state
+
+## Example: Sidebar
+
+Consider the case where the content within a sidebar needs to have conditional styles applied
+when the sidebar as whole is hovered.
+
+Using CSS variables, you can style descendants based on a parent's state, such as `:hover`.
+
+### Step 1
+Define one or more variables using `stylex.defineVars`:
+
+```tsx variables.stylex.ts
+// variables.stylex.ts
+import * as stylex from '@stylexjs/stylex';
+
+export const vars = stylex.defineVars({
+  childColor: 'black',
+});
+```
+
+### Step 2
+Define conditional styles setting the value for the variable in the ancestor component.
+
+```tsx
+import * as stylex from '@stylexjs/stylex';
+import { vars } from './variables.stylex';
+
+const styles = stylex.create({
+  parent: {
+    [vars.childColor]: {
+      default: 'black',
+      ':hover': 'blue',
+    },
+  },
+});
+
+function ParentWithHover({children}) {
+  return (
+    <div {...stylex.props(styles.parent)}>
+      {children}
+    </div>
+  );
+}
+```
+
+### Step 3
+Use the variable to style the child component
+
+```tsx
+import * as stylex from '@stylexjs/stylex';
+import { vars } from './variables.stylex';
+
+const styles = stylex.create({
+  row: {
+    color: vars.childColor,
+  }
+});
+
+function ParentWithHover() {
+  return (
+      <span {...stylex.props(styles.child)}><Icon />A Row</span>
+  );
+}
+```

apps/docs/docs/learn/06-recipes/_category_.json

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+{
+    "label": "Recipes",
+    "position": 4
+}