This shorthand property sets the thickness of all four sides of the element's border. Lengths may not be negative.
CSS Level | Value |
---|---|
CSS 2.1 | <border-width>{1,4}, where <border-width> is "thin", "medium", "thick", or a non-negative length |
CSS3 | <line-width>{1,4}, where <line-width> is "thin", "medium", "thick", or a non-negative length |