All that is needed to make a border around an element is border-style. The values that are applied can be solid, dotted, dashed, double, groove, ridge, inset and outset.

border-width is used to set the width of the border, which is measured in pixels. Other properties can include border-top-width, border-right-width, border-bottom-width and border-left-width.

At last, border-color is used to set the color.

Add the code below to the CSS file:

h2 { border-style: dashed; border-width: 3px; border-left-width: 10px; border-right-width: 10px; border-color: red; } 

This will result in a red dashed border appearing around all HTML secondary headers (the h2 element) which has 3 pixels width on the top and bottom and 10 pixels width on the left and right (the 3 pixel wide width of the entire border was overriden as a result).