# Introduction to Arc XP Blocks

Source: https://dev.arcxp.com/themes/introduction-to-arc-blocks/

Arc XP Blocks provides a set of reusable page templates, UI components, and content blocks that come out-of-the-box with your Arc XP bundle. By using Arc XP Blocks, you get the following benefits:

- Use a quick-launch tool kit of customizable components, blocks, and page templates.
- Receive components and blocks updates by deploying the latest Themes version release.
- Get full Arc XP support while using Arc XP Blocks.

See the Arc XP Blocks repositories:

[ Arc XP Blocks ](https://github.com/WPMedia/arc-themes-blocks) [ Arc XP Components ](https://github.com/WPMedia/arc-themes-components) 

## Supported browsers

Arc XP Blocks are supported on the two most recent versions of the following browsers:

- Google Chrome (desktop and Android)
- Microsoft Edge
- Mozilla Firefox (desktop and Android)
- Safari (macOS and iOS)

Other Chromium-based browsers, such as Opera and Samsung Internet, are also supported.

> **Note:**
> 
> Arc XP Blocks use [CSS logical properties](https://dev.arcxp.com/themes/developer-docs/css-logical-properties-on-arc-blocks/), which require Chrome and Edge 89 or later, Safari 15 or later, and Firefox 66 or later.

## How Arc XP Blocks work

Your Arc XP bundle includes a list of components and blocks in the `blocks.json` file. You can control the components and blocks available in your bundle by making changes to this file locally and redeploying your bundle. For more details, see [Local development process for custom blocks](https://dev.arcxp.com/themes/developer-docs/local-development-process-for-custom-blocks/).

### Requirements

When building and deploying a bundle, PageBuilder Engine validates the following requirements before making Arc XP Blocks available on your website:

- `blocks.json` file with valid settings in the root directory of your project.
- `arc-themes-components` package dependency in your project.
- Environment variables and personal access tokens.
- Version compatibility between PageBuilder Engine and `themesReleaseVersion`.

> **Tip:**
> 
> To configure local environment variables and create access tokens, see:
> 
> - [Configuring local environment variables](https://dev.arcxp.com/tutorials/quick-start/configure-local-environment-variables/)
> - [Using developer access tokens to access the Arc XP APIs](https://dev.arcxp.com/api/accessing-arcxp-apis/)

### Usage

Once you have set up Arc XP Blocks in your bundle, they become available in PageBuilder Editor, where you can select them and add them to your pages. Using the PageBuilder Editor UI, you can configure the Arc XP Blocks parameters through the Custom Fields section:

![Block custom fields](https://dev.arcxp.com/images/themes/blocksCustomFields-m.jpeg)

### Styling customization

Arc XP Blocks uses a design system that enables you to customize block styling without ejecting (forking) a block. The Themes design system is based on global tokens, breakpoints, and alias tokens, and leverages CSS logical properties. For more details on how to customize blocks styling, see:

- [Introduction to Themes design system](https://dev.arcxp.com/themes/developer-docs/introduction-to-themes-design-system/)
- [How to customize a block](https://dev.arcxp.com/themes/developer-docs/how-to-customize-a-block/)
- [Components and blocks storybook](https://dev.arcxp.com/themes/developer-docs/components-and-blocks-storybook/)

## Custom blocks

To create your custom blocks and use Arc XP Blocks as a starting point, you must eject (fork) the Arc XP block. See:

- [Local development process for custom blocks](https://dev.arcxp.com/themes/developer-docs/local-development-process-for-custom-blocks/)
- [Ejecting (forking) an Arc XP block](https://dev.arcxp.com/themes/developer-docs/ejecting-an-arc-block)

To create a custom block from the start and use the Themes design system, see [Creating a custom block with styling](https://dev.arcxp.com/themes/developer-docs/creating-a-custom-block-with-styling/).