allow single column span (#10)

* allow single column span

* retreat

* restore demo

* update bemness

README.md

@@ -66,10 +66,10 @@ The grid does not require the sidebar to maintain its layout.
 #### Layout Base
 The markup below ↓ will generate the ascii grid above ↑.  
 
-The main content section will constrain its _immediate_ children to its first column, with the exception of `table`s and `aside`s.
+The main content section will constrain its _immediate_ children to its first column, with the exception of `table`s and `aside`s.  
+If you want an element to span the full width of the main content area, you can apply the `o-layout__main__full-span` class to that element to achieve that effect.
 
-
-If you want an element to span the full width of the main content area, you can apply the `o-layout__main--full-span` class to that element to achieve that effect.
+_Note: `o-layout` styles tables to span two columns automatically. If you want a table to stick to a single column, you can apply_ `o-layout__main__single-span`, _instead. Every other element is styled to fit a single column._
 
 ```html
 <div class="o-layout" data-o-component="o-layout">

src/scss/_grid-areas.scss

@@ -97,7 +97,12 @@
 			@include oLayoutRule('right');
 		}
 
-		.#{$class}__main--full-span {
+		.#{$class}__main__single-span {
+			grid-column-end: 2;
+		}
+
+		.#{$class}__main--full-span,
+		.#{$class}__main__full-span {
 			grid-column-end: -1;
 		}
 	}
@@ -134,7 +139,7 @@
 			text-align: right;
 			margin-top: $_o-layout-gutter;
 		}
-		
+
 		border-left: 2px solid oColorsGetPaletteColor('teal');
 		padding: 0;
 		text-align: left;