update documentation for core installation

Author: dburles

packages/components/README.md

@@ -3,6 +3,8 @@
 
 Primitive layout, typographic, and other components for use with Theme UI.
 
+**Note:** This package is already included with the main `theme-ui` package, therefore a separate installation is not required.
+
 ```sh
 npm i @theme-ui/components
 ```

packages/core/README.md

@@ -5,12 +5,14 @@ Core Emotion and JSX implementation for Theme UI
 
 https://theme-ui.com
 
-**Note:** *This package is included in the main `theme-ui` package, and generally should not be used on its own.*
-
 ```sh
 npm i @theme-ui/core
 ```
 
+## Usage
+
+This package is already included in the main `theme-ui` package. However, for a minimal installation, it's possible to install this standalone and then subsequently install only the packages you require.
+
 ## API
 
 - `jsx`

packages/docs/src/pages/getting-started/index.mdx

@@ -4,13 +4,19 @@ title: Getting Started
 
 # Getting Started
 
-Install Theme UI.
+The `theme-ui` package includes a recommended set of packages out of the box, including [MDX support](/packages/mdx) and a set of [primitive UI components](/packages/components).
+However, if you would prefer a minimal installation, you can instead start with the `@theme-ui/core` package. For more information, see the [core package documention](/packages/core).
+
+## Setup
+
+#### 1. Install Theme UI:
 
 ```sh
 npm i theme-ui
 ```
 
-Create a theme object to include custom color, typography, and layout values.
+#### 2. Create a theme object
+Include custom color, typography, and layout values:
 
 ```js
 // example theme.js
@@ -34,7 +40,9 @@ If you're using Gatsby, see the [Getting Started with Gatsby](/getting-started/g
 
 </Note>
 
-Add the theme to your application with the `ThemeProvider`, passing in the `theme` object as a prop.
+#### 3. Add the theme to your application
+
+Using the `ThemeProvider`, pass in the `theme` object as a prop:
 
 ```jsx
 // basic usage

packages/docs/src/pages/packages/components.mdx

@@ -0,0 +1,7 @@
+---
+title: "@theme-ui/components"
+---
+
+import Readme from '@theme-ui/components/README.md'
+
+<Readme />

packages/docs/src/pages/packages/core.mdx

@@ -0,0 +1,7 @@
+---
+title: "@theme-ui/core"
+---
+
+import Readme from '@theme-ui/core/README.md'
+
+<Readme />

packages/docs/src/pages/packages/index.mdx

@@ -11,7 +11,8 @@ In addition to the core library, Theme UI includes several optional packages.
 
 <Cards width={320}>
 
-- [@theme-ui/components](/components)
+- [@theme-ui/core](/packages/core)
+- [@theme-ui/components](/packages/components)
 - [@theme-ui/presets](/packages/presets)
 - [@theme-ui/prism](/packages/prism)
 - [@theme-ui/color](/packages/color)

packages/docs/src/sidebar.mdx

@@ -48,6 +48,8 @@
   - [IconButton](/components/icon-button)
   - [MenuButton](/components/menu-button)
 - [Packages](/packages)
+  - [@theme-ui/core](/packages/core)
+  - [@theme-ui/components](/packages/components)
   - [@theme-ui/presets](/packages/presets)
   - [@theme-ui/prism](/packages/prism)
   - [@theme-ui/color](/packages/color)