Level: Basic
Not every visitor uses a mouse, and a site that can't be fully navigated by keyboard alone excludes a real portion of any audience.
Every Interactive Element Needs to Be Reachable by Tab
A visitor navigating by keyboard should be able to reach every link, button, and form field using the tab key, in a logical order.
Visible Focus Indicators Are Essential
A keyboard user needs a clear visual indication of which element currently has focus; removing this indicator for aesthetic reasons genuinely breaks keyboard usability.
Test by Actually Navigating Without a Mouse
The most reliable way to confirm keyboard accessibility is to genuinely try using the site with only a keyboard, rather than assuming it works.
Next step: Use the Get Source Code of Webpage to review your site's underlying structure to check whether interactive elements are set up to support proper keyboard navigation.