How to fix landmark complementary is top level on Shopify

Steps for Shopify

1. In your Shopify admin, go to Online Store → Themes → click 'Customize', then exit to code via Actions → Edit code.
2. Open the relevant layout or section file: for sitewide sidebars check `layout/theme.liquid`; for page-specific sidebars check the section file under `sections/` (e.g., `sections/product-template.liquid` or `sections/collection-template.liquid`).
3. Find the `<aside>` or `role="complementary"` element. If it is wrapped inside `<main>…</main>` or another landmark tag, cut the entire `<aside>` block out of that container.
4. Paste the `<aside>` block as a sibling of `<main>` — both should be direct children of a wrapping `<div>` that is itself a direct child of `<body>`, or directly inside `<body>`.
5. Use CSS in `assets/theme.css` (or your custom stylesheet) with Flexbox or Grid on the wrapper `<div>` to restore the two-column layout: `display: flex;` with `<main>` and `<aside>` as flex children.
6. Add `aria-label="[Descriptive name]"` to the `<aside>` tag, save all files, preview the theme, and verify with axe DevTools browser extension.

What is landmark complementary is top level?

Landmarks are special HTML "signposts" that screen readers use to let users jump directly to major sections of a page — the header, main content, navigation, footer, and sidebars. The "complementary" landmark (created by an `<aside>` tag or `role="complementary"`) is meant to mark supporting content that stands on its own alongside the main content, like a sidebar, related-links panel, or promotional widget. The WCAG rule "landmark-complementary-is-top-level" fires when that `<aside>` is placed inside another landmark (for example, inside a `<main>`, `<header>`, or `<section>` with a role), rather than sitting directly inside the `<body>` at the top level of the page.

Screen reader users — including customers with visual impairments — rely on landmark navigation to quickly skip around a page without listening to everything. When a complementary landmark is buried inside another landmark, screen readers either misreport its purpose or completely hide it from the landmark list, making it impossible for these users to find your sidebar content (promotions, related products, trust badges, support widgets) efficiently. This is a WCAG 2.1 Success Criterion 1.3.6 (Identify Purpose) and best-practice landmark structure issue, and repeated accessibility failures create legal exposure under laws like the ADA (US), EAA (EU), and AODA (Canada). Fixing it improves the experience for the roughly 7 million screen reader users in the US alone, reduces legal risk, and signals to Google that your page is well-structured.

See the complete Landmark complementary is top level guide for every platform and the full background.