outline-offset
The outline-offset CSS property is used to set space between an outline and the edge or border of an element. An outline is a line that is drawn around elements, outside the border edge.
Example
<!DOCTYPE html> <html> <head> <style> div { margin: 20px; width: 150px; padding: 10px; height: 70px; border: 2px solid black; outline: 2px solid red; outline-offset: 15px; } </style> </head> <body> <p> <b>Note:</b> Internet Explorer does not support the outline-offset property. </p> <div> This div has an outline border 15px outside the border edge. </div> </body> </html>