[css-align-3] Define baselines of a line box to make block/multicol definitions easier to read

Author: fantasai

css-align-3/Overview.bs

@@ -2181,12 +2181,17 @@ Determining the Baselines of a Box</h2>
 	are determined differently based on the layout model, as follows:
 
 	<dl>
+		<dt>line box
+		<dd>
+			The first/last [=baseline set=] of a line box
+			is <a>generated</a> from the dominant baseline
+			and the font settings of its [=root inline box=].
+
 		<dt>block containers
 		<dd>
 			The first/last [=baseline set=] of a <a>block container</a>
-			is <a>generated</a> from the dominant first/last baseline
-			of the first/last in-flow line box in the block container,
-			or is taken from the first/last in-flow block-level child in the block container
+			is taken from the first/last in-flow line box in the block container
+			or the first/last in-flow block-level child in the block container
 			that contributes a set of first/last baselines,
 			whichever comes first/last.
 			If there is no such line box or child,
@@ -2200,11 +2205,10 @@ Determining the Baselines of a Box</h2>
 		<dt>multi-column containers
 		<dd>
 			The first [=baseline set=] of a <a>multi-column container</a>
-			is <a>generated</a> from the dominant first baseline
-			of the first in-flow line box in the first column box,
-			or is taken from the first in-flow block-level child
-			that contributes a set of first baselines,
-			whichever comes first.
+			is taken from the first/last in-flow line box in the block container
+			or the first/last in-flow block-level child in the block container
+			that contributes a set of first/last baselines,
+			whichever comes first/last.
 			If there is no such line box or child,
 			then the multi-column container has no first [=baseline set=].
 

css-flexbox-1/Overview.bs

@@ -31,7 +31,7 @@ Former Editor: Neil Deakin, Mozilla Corporation, enndeakin@gmail.com
 Former Editor: Ian Hickson, formerly of Opera Software, ian@hixie.ch
 Former Editor: David Hyatt, formerly of Netscape Corporation, hyatt@apple.com
 !Issues List: <a href="https://drafts.csswg.org/css-flexbox-1/issues">https://drafts.csswg.org/css-flexbox-1/issues</a>
-Ignored Terms: auto, first formatted line, first letter, static position
+Ignored Terms: auto, first formatted line, first letter
 Ignored Vars: item’s own max-content, maximum min-content among all items
 WPT Path Prefix: css/css-flexbox/
 </pre>