---
pagination_prev: null
title: Use CSS in Blockly - Codelab Overview
description: Overview of the CSS in Blockly codelab
---

# Use CSS in Blockly

## 1. Codelab overview

### What you'll learn

In this codelab you will learn how to use CSS to customize the colours of:

- Components
- Categories
- Blocks

If you don't need the fine-grained control provided by CSS, consider using
themes instead. For more information, see the
[Customizing your themes](/codelabs/theme-extension-identifier/codelab-overview)
codelab.

### What you'll build

A simple Blockly workspace that uses the same Halloween colours as the [Customizing your themes](/codelabs/theme-extension-identifier/codelab-overview) codelab.

### What you'll need

- A browser
- Basic knowledge of HTML, CSS, SVG, and JavaScript.
- Basic knowledge of your browser's developer tools.
- Basic understanding of Blockly, including workspace components, category toolboxes, block definitions, and themes.

This codelab is focused on using CSS with Blockly. Non-relevant concepts are glossed over and provided for you to simply copy and paste.
