[css-grid] Tweak further.

Author: tabatkins

css-grid/Overview.bs

@@ -3022,9 +3022,8 @@ Definition of Terms for use in Calculating Grid Track Sizes</h3>
 
 		<dt><dfn>remaining space</dfn>
 		<dd>
-			Equal to the <a>available space</a> minus the sum of the <a>base sizes</a> of all the grid tracks
-			or zero,
-			whichever is greater.
+			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.
 

css-grid/Overview.html

@@ -2996,9 +2996,8 @@ <h3 class="heading settled heading" data-level=11.1 id=algo-terms><span class=se
 
 		<dt><dfn data-dfn-type=dfn data-noexport="" id=remaining-space>remaining space<a class=self-link href=#remaining-space></a></dfn>
 		<dd>
-			Equal to the <a data-link-type=dfn href=#available-space title="available space">available space</a> minus the sum of the <a data-link-type=dfn href=#base-size title="base sizes">base sizes</a> of all the grid tracks
-			or zero,
-			whichever is greater.
+			Equal to the <a data-link-type=dfn href=#available-space title="available space">available space</a> minus the sum of the <a data-link-type=dfn href=#base-size title="base sizes">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 data-link-type=dfn href=#base-size title="base sizes">base sizes</a> are adjusted.