How to fix landmark complementary is top level on Webflow

Steps for Webflow

1. Open your Webflow project in the Designer and locate the page or component containing the sidebar.
2. In the Navigator panel (left sidebar), find the element set to Tag: `<aside>` (or a Div with a custom attribute `role="complementary"`).
3. Check its parent in the Navigator tree. If it is nested inside an element tagged as `<main>`, `<header>`, `<nav>`, or `<footer>`, drag it out in the Navigator so it becomes a sibling of `<main>` under the same parent wrapper Div.
4. Set the parent wrapper Div's display to Flex or Grid (Layout panel on the right) so `<main>` and `<aside>` sit side by side visually.
5. Select the `<aside>` element, open Element Settings (D key), and add a custom attribute: Name `aria-label`, Value `[Descriptive sidebar name]`.
6. Publish the project and verify with axe DevTools on the published URL.

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.