| Valid value | Description |
|---|
| none | No rule, forces rule-thickness to 0. |
| dotted | A series of dots. |
| dashed | A series of short line segments. |
| solid | A single line segment. |
| double | Two solid lines. The sum of the two lines and the space between them equals the value of "rule-thickness". |
| groove | The rule looks as though it were carved into the canvas. (Top/left half of the rule's thickness is the color specified; the other half is white.) |
| ridge | The opposite of "groove", the rule looks as though it were coming out of the canvas. (Bottom/right half of the rule's thickness is the color specified; the other half is white.) |
| inherit | |