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Add Custom CSS Styles

Apply custom styles to control the appearance of your content. Custom CSS lets you fine-tune spacing, colors, fonts, and layout in an Edition beyond what the standard formatting controls offer — useful for matching brand guidelines or reusing a house style across Broadcasts.

Before you begin​

  • Work in an Edition where you have access to the raw HTML or a custom-CSS/style area of the editor (confirm the exact location in your account).
  • Know that email clients vary widely in CSS support. Inline styles and simple, table-friendly rules render most reliably; many clients strip or ignore <style> blocks, external stylesheets, and advanced selectors.
  • Have your brand values ready — hex colors, font stacks, and pixel sizes — so styling stays consistent across Editions.
  • Plan to test before you send. Custom CSS that looks right in the editor can render differently in Outlook, Gmail, and mobile apps.

Steps​

  1. Open the Edition and locate the block or region you want to style.
  2. Add your CSS. For the most reliable results, apply styles inline on the element (for example, a style attribute on a table cell or paragraph). If a shared style block is available, place reusable rules there (confirm the exact steps in your account).
  3. Keep selectors simple and use web-safe font stacks with fallbacks (for example, Arial, Helvetica, sans-serif). Avoid positioning, floats, and background images as the only carrier of important content.
  4. Save your changes.
  5. Send yourself a preview or test Broadcast and check it across at least one desktop client, one webmail client, and a mobile device.

Result​

Your custom styling appears consistently in the preview and test messages. When it renders as expected across the clients your subscribers use, the Edition is ready to schedule or send.

Canonical terms: Author, Edition, Folder (Project Folder), Broadcast. See the Glossary.