This property controls the thickness (width) of the bottom border of an element's rendering box. Negative values are not allowed.
This is a Test
Explicitly sets the value of this property to that of the parent.
thin | medium | thick:
Renders a "thin", "medium" or "thick" border on the bottom side of the element's rendering box. The actual thickness of these border values is not specified, but "thin" should have a smaller thickness than "medium", which should have a smaller thickness than "thick".
Sets the width of the border on the bottom side of the element's rendering box to an explicit measurement.