Set the bottom border of the element. If you would like to place a border on only one side of an HTML element, or maybe have a unique look for each side of the border, then use border-(direction).

Value Description
size px - size in terms of pixels
em - size in terms of the current font size
in - size in terms of inches
cm - size in terms of centimeters
color Hexadecimal - a pound sign (#) followed by at most 6 hex values(0-F).
RGB - individual values for Red, Green, and Blue.
color term - sets the color using names. i.e. red, orange, white, etc.
width-key-term Define the border width with key terms. Available terms: thin, medium, and thick.


p { border-bottom: 15px solid black; }


This element only has a bottom border.