diff --git a/opensmiles.asciidoc b/opensmiles.asciidoc
index 627cb45..da7d3a4 100644
--- a/opensmiles.asciidoc
+++ b/opensmiles.asciidoc
@@ -452,11 +452,11 @@ later in the string, a bond is made between the two atoms, which typically
 forms a cyclic structure.
 
 [options="header",frame="topbot",grid="rows",width="90%"]
-|==================================================================================
-| Depiction                               | SMILES           | Name
-| image:depict/cyclohexane.gif[]          | `C1CCCCC1`       | cyclohexane
-| image:depict/perhydroisoquinoline.gif[] | `N1CC2CCCC2CC1`  | perhydroisoquinoline
-|==================================================================================
+|===================================================================================
+| Depiction                               | SMILES            | Name
+| image:depict/cyclohexane.gif[]          | `C1CCCCC1`        | cyclohexane
+| image:depict/perhydroisoquinoline.gif[] | `N1CC2CCCCC2CC1`  | perhydroisoquinoline
+|===================================================================================
 
 If a bond symbol is present between the atom and rnum, it can be
 present on *either or both* bonded atoms.  However, if it appears on