Property Reference - CSS Reference - page 176

Name
column-rule-style
Values:
<'border-style'>
Initial value:
none
Applies to:
Elements laid out using multiple columns
Inherited:
No
Computed value:
Same as declared value
Description:
Defines the style of the “rules” (vertical lines) drawn between columns in an element laid out
with multiple columns. The values are the same as for the property border-style . Either of
the values none (the default) or hidden means no rule will be drawn.
Examples:
#d01 {column-rule-style: solid;}
#d02 {column-rule-style: dashed;}