Custom CSS and code

Applies to: Local 4.2.1 and later. Added in: Local 1.0.0. Last checked: 2026-10-13 against Local 4.2.1.

Krown support does not provide help with custom code. This page lists the places where you or a developer can add your own CSS, HTML or Liquid to Local, from the safest to the riskiest, and what happens to that code when you update the theme.

Custom CSSCopy Anchor Link

• Theme settings → Custom CSS applies your CSS to every page. It is a Shopify feature that every theme has, not a Local setting. Shopify limits it to 1,500 characters and does not allow @import.
• Custom CSS at the bottom of each section's settings applies CSS to that one section on that page only. Shopify limits it to 500 characters.

See Add custom CSS in the Shopify Help Center. Ready-made CSS for Local is on Code tweaks.

HTML and Liquid on a pageCopy Anchor Link

Use the Custom HTML / Liquid section or block. Both are part of Local and need no file edits:

• The Custom HTML / Liquid section adds a full-width area with your code, on any page.
• The Custom Liquid block adds code inside a Flex section, next to other blocks.
• The product page has its own Custom HTML / Liquid block, see Product content blocks.

For code in the <head> of every page, such as verification or tracking tags, use an app or an app embed. See Insert code into your store's head.

Editing theme filesCopy Anchor Link

Shopify admin → Online Store → Themes → … → Edit code opens the theme files. Local's files are built from its source code: many files in assets/ are compiled, and the snippets/ and sections/ files change between versions. See Edit the theme code for how the code editor works.

Before you edit a file, duplicate the theme (Online Store → Themes → … → Duplicate) and work on the copy.

Code changes and theme updatesCopy Anchor Link

• Custom CSS, section Custom CSS and the code in Custom HTML / Liquid sections and blocks are settings. Shopify carries them over when you update Local. Check them after each update: a new version can change the HTML or the class names your code targets.
• Edits to theme files are carried over only when they do not conflict with the update. Otherwise, you or your developer must make them again in the new version.
• An edited file in assets/, for example a JavaScript component, is replaced by the new version's file on update.

See Update Local.

How do I tell whether a problem comes from my custom code?Copy Anchor Link

Test the same page in a fresh copy of Local installed from the Shopify Theme Store. If the problem does not happen in the fresh copy, it comes from a code edit or an app in your theme. See Troubleshoot store issues: first steps.

How do I undo a change to a theme file?Copy Anchor Link

Open the file in the code editor and choose an older version: Shopify keeps the earlier versions of each file. See Edit theme code in the Shopify Help Center.

Related pagesCopy Anchor Link

• Code tweaks: CSS and code for common changes.
• Custom fonts: add a font that is not in the Shopify font library.
• Custom work and code changes: who to contact when a change needs code.