---
title: "Custom CSS"
slug: "custom-css"
updated: 2026-10-20T19:31:42Z
published: 2026-10-20T19:31:42Z
canonical: "docs.blackthorn.io/custom-css"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blackthorn.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom CSS

Go to **Site Settings → Custom CSS** to write or paste any valid CSS. It applies immediately to your entire published page.

**You probably won't need this often.** The Page Designer gives you granular visual control over every component: colors, spacing, fonts, borders, shadows, corner radius, and more are all configurable directly in each component's settings panel without writing a single line of CSS.

But for those edge cases where you need to target a very specific element or override a style that isn't exposed in the UI, Custom CSS is your escape hatch. Previously in Blackthorn Events, applying custom styles required hosting a separate CSS file externally and referencing it. Now you can simply paste your CSS here and it applies everywhere: no file hosting, no URLs, no waiting.

Common legitimate uses:

- Targeting a very specific nested element the settings panel doesn't expose
- Adding a CSS animation or transition not available in the UI
- Overriding a third-party embed's default styles

⚠️CSS here overrides everything on the page, including theme tokens. Changes can be hard to debug. Always prefer using the component settings panel first, and treat Custom CSS as a last resort.

---

![Site Settings → Custom CSS: paste any valid CSS to apply page-wide](https://cdn.document360.io/f977eec0-500f-40a3-b663-724a51f78075/Images/Documentation/ss_custom_css.jpg)Site Settings → Custom CSS: paste any valid CSS to apply page-wide