[css-grid] Better heading structure for Grid Sizing Algo

Author: fantasai

css-grid/Overview.bs

@@ -2586,50 +2586,12 @@ Grid Baselines</h3>
 
 
 <h2 id='layout-algorithm'>
-Grid Sizing Algorithm</h2>
+Grid Sizing</h2>
 
 	This section defines the <dfn export>grid sizing algorithm</dfn>,
 	which determines the size of all <a>grid tracks</a>
 	and, by extension, the entire grid.
 
-<h3 id='algo-terms'>
-Definition of Terms for use in Calculating Grid Track Sizes</h3>
-
-	<dl>
-		<dt><dfn>min track sizing function</dfn>
-		<dd>
-			If the track was sized with a ''minmax()'' function,
-			this is the first argument to that function.
-			Otherwise, it's the track's sizing function.
-
-		<dt><dfn>max track sizing function</dfn>
-		<dd>
-			If the track was sized with a ''minmax()'' function,
-			this is the second argument to that function.
-			Otherwise, it's the track's sizing function.
-
-		<dt><dfn>available space</dfn>
-		<dd>
-			The <a>grid container</a>’s content box size in the applicable dimension.
-
-		<dt><dfn>free space</dfn>
-		<dd>
-			Equal to the <a>available space</a> minus the sum of the <a>base sizes</a> of all the grid tracks,
-			clamped to a minimum of zero.
-			This value can change over the course of the algorithm,
-			as <a>base sizes</a> are adjusted.
-
-			If <a>available space</a> is <a>indefinite</a>,
-			the <a>free space</a> is <a>indefinite</a> as well.
-
-		<dt><dfn>span count</dfn>
-		<dd>
-			The number of <a>grid tracks</a> crossed by a <a>grid item</a> in the applicable dimension.
-	</dl>
-
-<h3 id='algo-overview'>
-Overall Sizing Algorithm</h3>
-
 	Each track has specified <a title="min track sizing function">minimum</a> and
 	<a title="max track sizing function">maximum</a> <a>sizing functions</a>
 	(which may be the same).
@@ -2643,6 +2605,9 @@ Overall Sizing Algorithm</h3>
 
 	The <a>grid sizing algorithm</a> defines how to resolve these sizing constraints into used track sizes.
 
+<h3 id="algo-overview">
+Grid Sizing Algorithm</h3>
+
 	<ol>
 		<li>
 			First, the <a>track sizing algorithm</a> is used to resolve the sizes of the <a>grid columns</a>.
@@ -2683,6 +2648,44 @@ Overall Sizing Algorithm</h3>
 	Once the size of each <a>grid area</a> is thus established,
 	the <a>grid items</a> are laid out into their respective containing blocks.
 
+<h3 id='algo-terms'>
+Track Sizing Terminology</h3>
+
+	<dl>
+		<dt><dfn>min track sizing function</dfn>
+		<dd>
+			If the track was sized with a ''minmax()'' function,
+			this is the first argument to that function.
+			Otherwise, it's the track's sizing function.
+
+		<dt><dfn>max track sizing function</dfn>
+		<dd>
+			If the track was sized with a ''minmax()'' function,
+			this is the second argument to that function.
+			Otherwise, it's the track's sizing function.
+
+		<dt><dfn>available space</dfn>
+		<dd>
+			The <a>grid container</a>’s content box size in the applicable dimension.
+
+		<dt><dfn>free space</dfn>
+		<dd>
+			Equal to the <a>available space</a> minus the sum of the <a>base sizes</a> of all the grid tracks,
+			clamped to a minimum of zero.
+			This value can change over the course of the algorithm,
+			as <a>base sizes</a> are adjusted.
+
+			If <a>available space</a> is <a>indefinite</a>,
+			the <a>free space</a> is <a>indefinite</a> as well.
+
+		<dt><dfn>span count</dfn>
+		<dd>
+			The number of <a>grid tracks</a> crossed by a <a>grid item</a> in the applicable dimension.
+	</dl>
+
+<h3 id="algo-track-sizing">
+Track Sizing Algorithm</h3>
+
 	The remainder of this section is the <dfn>track sizing algorithm</dfn>,
 	which calculates from the <a title="min track sizing function">min</a> and <a>max track sizing functions</a>
 	the used track size.
@@ -2697,9 +2700,9 @@ Overall Sizing Algorithm</h3>
 
 	<ol>
 		<li><a href="#algo-init">Initialize Track Sizes</a>
-		<li><a href="#algo-content">Resolve Content-Based Track Sizing Functions</a>
-		<li><a href="#algo-grow-tracks">Grow All Tracks To Their Max</a>
-		<li><a href="#algo-flex-tracks">Process Flexible Tracks</a>
+		<li><a href="#algo-content">Resolve Intrinsic Track Sizes</a>
+		<li><a href="#algo-grow-tracks">Maximize Tracks</a>
+		<li><a href="#algo-flex-tracks">Stretch Flexible Tracks</a>
 	</ol>
 
 <h3 id="algo-init">
@@ -2741,7 +2744,7 @@ Initialize Track Sizes</h3>
 	</dl>
 
 <h3 id="algo-content">
-Resolve Content-Based Track Sizing Functions</h3>
+Resolve Intrinsic Track Sizes</h3>
 
 	This step resolves intrinsic track <a>sizing functions</a> to absolute lengths.
 	First it resolves those sizes based on items that are contained wholly within a single track.
@@ -2900,7 +2903,7 @@ Resolve Content-Based Track Sizing Functions</h3>
 
 
 <h3 id="algo-grow-tracks">
-Grow All Tracks To Their Max</h3>
+Maximize Tracks</h3>
 
 	If the <a>free space</a> is positive, distribute it equally to all tracks,
 	freezing tracks as they reach their <a>growth limits</a>
@@ -2913,7 +2916,7 @@ Grow All Tracks To Their Max</h3>
 	the <a>free space</a> is zero.
 
 <h3 id="algo-flex-tracks">
-Process Flexible Tracks</h3>
+Stretch Flexible Tracks</h3>
 
 	This step sizes flexible tracks
 	using the largest value it can assign to an ''fr''