Singleborder

Singleborder refers to a styling approach where an interface element is outlined or separated by a single line, rather than a complete rectangular frame or multiple bordering lines. The effect is to create a clean, minimal delineation that draws attention without heavy enclosure.

In web and app design, singleborder is often implemented as a bottom border under input fields (the underline style) or as a left or top accent border on cards or panels. It is popular in flat and material-inspired design for its simplicity and scannability.

In print and typography, the term can describe a frame that uses one continuous line around content, typically on a single edge or along the inner edge of a block quote. This usage emphasizes a single boundary to separate content from surrounding space without a full enclosure.

Implementation considerations include contrast, thickness, and color to harmonize with surrounding UI. Designers should consider accessibility, readability, and how the border behaves in different screen sizes and densities. The style is commonly used to provide subtle guidance or emphasis, while maintaining a lightweight visual language.

History and usage: The term is informal and not part of formal typography or CSS specifications. It appears in design discussions, blogs, and product documentation as a shorthand for minimal border styling. As a flexible concept, singleborder can be adapted across digital and print contexts to balance emphasis with openness.