The border-top-style property sets the style of an element's top border.
The border-top-style CSS property sets the style of an element's top border individually. However in many cases the shorthand CSS properties like border-style or border-top are more convenient to use and preferable.
This CSS tutorial explains how to use the CSS property called border-top-style with syntax and examples.
border-top-style: none|hidden|dotted|dashed|solid|double|groove|ridge|inset|outset|initial|inherit;