[css-align] Some minor cleanup of baseline stuff.

--HG--
extra : rebase_source : 056d2d397b85e23130968672ff974f1da551c869

Author: fantasai

css-align/Overview.bs

@@ -281,24 +281,24 @@ Baseline Alignment: the ''baseline'' and ''last-baseline'' keywords</h3>
 		<dt><dfn>baseline</dfn>
 		<dd>
 			Indicates <dfn>first-baseline alignment</dfn>:
-			aligns the box's <a>first baseline</a>
-			with the <a>first baselines</a>
+			aligns one of the box's <a>first baselines</a>
+			with the corresponding <a>first baselines</a>
 			of all the boxes in its <a>baseline-sharing group</a>.
 
 			If the <a>alignment subject</a>’s position is not fully determined by <a>baseline alignment</a>,
 			the content is ''self-start''-aligned insofar as possible while preserving the baseline alignment.
-			(Content that has no <a>first baseline</a> is thus start-aligned.)
+			(Content that has no <a>first baselines</a> is thus start-aligned.)
 
 		<dt><dfn>last-baseline</dfn>
 		<dd>
 			Indicates <dfn>last-baseline alignment</dfn>:
-			aligns the box's <a>last baseline</a>
-			with the <a>last baselines</a>
+			aligns one of the box's <a>last baselines</a>
+			with the corresponding <a>last baselines</a>
 			of all the boxes in its <a>baseline-sharing group</a>.
 
 			If the <a>alignment subject</a>’s position is not fully determined by <a>baseline alignment</a>,
 			the content is ''self-end''-aligned insofar as possible while preserving the baseline alignment.
-			(Content that has no <a>last baseline</a> is thus end-aligned.)
+			(Content that has no <a>last baselines</a> is thus end-aligned.)
 	</dl>
 
 	When specified for 'align-content'/'justify-content',
@@ -895,82 +895,76 @@ Block/Cross-Axis Alignment: the 'align-items' property</h3>
 <h2 id='baseline-rules'>
 Determining the Baseline of a Box</h2>
 
-	The <dfn>first baseline</dfn> (and <dfn>last baseline</dfn>) of a box
+	The <dfn title="baselines of a box"></dfn><dfn>first baselines</dfn> (and <dfn>last baselines</dfn>) of a box
 	for a given axis
-	is a set of baselines (alphabetic, central, etc.)
-	nominally associated with a line of text within the box.
+	are a set of baselines (alphabetic, central, etc.)
+	nominally associated with the first (last) line of text within the box.
 	The <a>alignment baseline</a> is one of these,
 	usually the dominant baseline of the <a>alignment container</a>.
-	(Note, however, that boxes might not have a baseline in a particular axis.)
+	(See 'alignment-baseline'.)
+	Note that boxes might not have baselines in a particular axis.
 
-	The first and last baselines of a box are determined differently based on the layout model, as follows:
+	The first and last <i>baselines of a box</i>
+	are determined differently based on the layout model, as follows:
 
 	<dl>
-		<dt>''block''
-		<dt>''list-item''
+		<dt>block containers
 		<dd>
-			The first (last) inline-axis baseline of a block
-			is generated from the dominant baseline of the first (last) in-flow line box in the block,
-			or is taken from the first (last) in-flow block-level child in the block that has a baseline,
+			The first (last) inline-axis baselines of a block container
+			are generated from the dominant baseline of the first (last) in-flow line box in the block container,
+			or are taken from the first (last) in-flow block-level child in the block container that contributes a set of baselines,
 			whichever comes first (last).
 			If there is no such line box or child,
-			then the block has no baseline.
-			For the purposes of finding a baseline,
+			then the block container has no baselines.
+			For the purposes of finding the baselines,
 			in-flow boxes with a scrolling mechanisms (see the 'overflow' property)
 			must be considered as if scrolled to their origin (final) position.
 
-			A block has no block-axis baseline.
+			A block container has no block-axis baselines.
 
-		<dt>''table''
+		<dt>tables
 		<dd>
-			The first (last) inline-axis baseline of a table box is the baseline of its first (last) row.
-			However, when finding the baseline of an inline-block,
-			any baselines contributed by the table boxes must be skipped.
-			(This quirk is a legacy behavior from [[CSS21]].)
+			The first (last) inline-axis baselines of a table box are
+			the baselines of its first (last) row.
 
-			The block-axis baseline of a table box is the baseline of its first (last) column.
+			When finding the baselines of an inline-block,
+			any baselines contributed by table boxes must be skipped.
+			(This quirk is a legacy behavior from [[CSS21]].)
 
-			<p class='issue'>
-				Or should it have no baseline?
+			The block-axis baselines of a table box are the baselines of its first (last) column.
 
-		<dt>''table-row''
+		<dt>table rows
 		<dd>
 			If any cells in the row participate in ''baseline'' (''last-baseline'') alignment along the row axis,
-			the first (last) inline-axis baseline of the row is
-			generated from their shared <a>alignment baseline</a> and the row's <a>first available font</a>,
+			the first (last) inline-axis baselines of the row
+			are generated from their shared <a>alignment baseline</a>
+			and the row's <a>first available font</a>,
 			after alignment has been performed.
-			Otherwise, the first (last) inline-axis baseline of the row
-			is synthesized from the lowest and highest content edges of the cells in the row.
+			Otherwise, the first (last) inline-axis baselines of the row
+			are synthesized from the lowest and highest content edges of the cells in the row.
 			[[!CSS21]]
 
-			A table row has no block-axis baseline.
+			A table row has no block-axis baselines.
 
-		<dt>''table-column''
+		<dt>table columns
 		<dd>
 			If any cells in the column participate in ''baseline'' (''last-baseline'') alignment
 			along the column axis (by having a writing mode perpendicular to that of the table),
-			the first (last) block-axis baseline of the column is
-			generated from their shared <a>alignment baseline</a> and the column's <a>first available font</a>,
+			the first (last) block-axis baselines of the column
+			are generated from their shared <a>alignment baseline</a>
+			and the column's <a>first available font</a>,
 			after alignment has been performed.
-			Otherwise, the the first (last) inline-axis baseline of the row
-			is synthesized from the extreme content edges of the cells in the row.
+			Otherwise, the the first (last) inline-axis baselines of the row
+			are synthesized from the extreme content edges of the cells in the row.
 			[[!CSS21]]
-			
-			A table column has no inline-axis baseline.
-
-		<dt>''table-cell''
-		<dd>
-			The inline-axis baseline of a table cell is the baseline of the first (last) in-flow line box in the cell,
-			or the first (last) in-flow element that contributes a baseline in that axis,
-			whichever comes first (last).
 
-			A table cell has no block-axis baseline.
+			A table column has no inline-axis baselines.
 
-		<dt>''flex''
+		<dt>flex containers
 		<dd>
 			See <a href="http://www.w3.org/TR/css3-flexbox/#flex-baselines">Flex Baselines</a> in [[!CSS3-FLEXBOX]].
 
-		<dt>''grid''
+		<dt>grid containers
 		<dd>
 			See <a href="http://www.w3.org/TR/css3-grid-layout/#grid-baselines">Grid Baselines</a> in [[!CSS3-GRID-LAYOUT]].
 	</dl>