> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://staging.chrisp.chat/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Add Theme Code to through extension

Here is how you can add custom code to your app in the simplest way.

1. Open the **F: Theme Access: Insert CSS** app and click on the **Enable** **and Configure** button. Even if you already enabled it before, you will be redirected to the theme customisation page.

![](https://storage.crisp.chat/users/helpdesk/website/8a0529da2c4da000/fcbe8c8e-6942-4988-8d76-77bd8d_1d1pe4a.png)

2. Now you can see three input boxes: Insert HTML, Insert CSS, and Insert JS.

![](https://storage.crisp.chat/users/helpdesk/website/88fed3f29ffc100/89b8e960-7176-4dcf-b28b-11144b_7cfjek.png)

3. In the _Insert HTML_ section, you can paste your HTML code and also add your CSS data to insert _Insert CSS_. Here is an example of how I added my code.

![](https://storage.crisp.chat/users/helpdesk/website/2f1330a218615e00/b53e0d12-cf08-4013-a0d0-50ee0f_1852spq.png)

Most of the time, you won't need to add any JS (javascript) codes, which may only be used in some special cases. This will help you make your codes more advanced.