> For the complete documentation index, see [llms.txt](https://devnex.gitbook.io/comi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://devnex.gitbook.io/comi/overview/getting-started/installation-comi/7th-install-child-theme.md).

# 7th - Install Child Theme

If you need to modify core files or just need a better way to manage custom CSS code, we recommend using the child theme.

The fastest way to install the child theme is by going to **Appearance** ->  **Themes** - Install & Activate Child theme.

<figure><img src="https://4240099660-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F5LLOBHpYqYVKKoFTsH7P%2Fuploads%2FLDYB00YLl1yE7ZzQ2Bu3%2F%E1%BA%A3nh.png?alt=media&amp;token=b0e48a40-4fb5-48d6-8ae1-7a5ce9592221" alt=""><figcaption></figcaption></figure>

Now that you have the child theme active, you can start adding your custom CSS into the child theme style.css file, or your custom PHP code in **functions.php** file,  via **Appearance -> Theme File Editor**.

<figure><img src="https://4240099660-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F5LLOBHpYqYVKKoFTsH7P%2Fuploads%2FoXbHFI3ucr6azhWdxmqA%2F%E1%BA%A3nh.png?alt=media&amp;token=37b56c95-a3f2-43e5-8015-91f52e77fdc7" alt=""><figcaption></figcaption></figure>