The appearance of a page or component when no content is available, such as an empty search results or new user dashboard. Well-designed empty states guide users toward actions that populate the interface. Include helpful messaging and clear calls to action rather than leaving users stranded.

The visual appearance of an element when a user's cursor is positioned over it, providing feedback and indicating interactivity. Hover states are essential for buttons, links, and clickable elements—without them, users can't tell what's interactive. Remember that hover doesn't exist on touch devices, so don't rely on it for essential information.

The ability to navigate and interact with a website using only keyboard controls, essential for accessibility. Test tab order, focus visibility, and keyboard-activated interactions to ensure full functionality. Many users rely on keyboard navigation due to motor disabilities or preference.

The current condition of a component or interface element, such as default, hover, active, loading, or error. Managing state effectively enables responsive, interactive experiences. Design all relevant states and transitions between them.

The tabindex attribute controls whether an element can receive keyboard focus and in what order. Use 0 to include an element in natural tab order and -1 for programmatic focus only. Avoid positive values because they create confusing navigation order.

Empty space in a design that provides visual breathing room and separation between elements. Whitespace improves readability, focus, and perceived quality of designs. Resist filling every available space—whitespace is an active design element.

The initial appearance of an interface when empty of user content, requiring thoughtful design to guide action. Zero states should welcome users and clearly explain how to add content. Design engaging zero states that reduce new-user confusion.

The empty area around and between design elements that gives content room to breathe and creates visual clarity. Negative space, or white space, is an active design element that improves focus and comprehension. Resist filling every available space—negative space makes designs feel premium.

Inclusion is a design principle focused on creating experiences that are welcoming, usable, and respectful for diverse users and contexts.

Usability measures how effectively, efficiently, and satisfactorily users can achieve goals within a system or interface.