[css-multicol-1] Tidying up figures

Making figures more accurate and fixing some example code to help with clarity of diagrams.

Author: rachelandrew

css-multicol-1/Overview.bs

@@ -18,7 +18,7 @@ Previous Version: https://www.w3.org/TR/2001/WD-css3-multicol-20010118/
 Previous Version: http://www.w3.org/1999/06/WD-css3-multicol-19990623
 Editor: Håkon Wium Lie, Opera Software, howcome@opera.com, w3cid 9796
 Editor: Florian Rivoal, On behalf of Bloomberg, https://florian.rivoal.net, w3cid 43241
-Editor: Rachel Andrew, Invited Expert, https://rachelandrew.co.uk, w3cid 81117
+Editor: Rachel Andrew, Fronteers, https://rachelandrew.co.uk, w3cid 81117
 Issue Tracking: Disposition of Comments https://drafts.csswg.org/css-multicol-1/issues
 Abstract: This specification describes multi-column layouts in CSS, a style sheet language for the web. Using functionality described in the specification, content can be flowed into multiple columns with a gap and a rule between them.
 Link Defaults: css-color (property) color, css2 (property) max-height, css-backgrounds-3 (value) hidden
@@ -198,9 +198,12 @@ The multi-column model</h2>
 
 		<figure>
 			<img alt="a diagram showing the various parts of multi-column layout" src="images/initial-example.svg">
+			<img alt="key to the conventions used to display invisible parts of diagram" src="images/invisible-elements.svg">
 			<figcaption>A multi-column layout with the non-visible column-span and padding inside the multicol container highlighted.</figcaption>
 		</figure>
 
+		
+
 		<figure>
 			<img alt="a diagram showing the various parts of multi-column layout" src="images/initial-example-b.svg">
 			<figcaption>The same layout as in the first image, as it would be displayed by an implementation.</figcaption>
@@ -847,8 +850,8 @@ Column gaps and rules</h2>
 
 		<pre highlight="css">
 		body {
-			column-gap: 1em;
-			column-rule-width: 1em;
+			column-gap: 35px;
+			column-rule-width: 35px;
 			column-rule-style: solid;
 			column-rule-color: black;
 		}
@@ -1075,11 +1078,11 @@ h2 {
 
 		<pre highlight="css">
 		h2 {
-			margin: 0.5em 0;
+			margin: 16px 0;
 			column-span: all;
 			background: silver
 		}
-		p { margin-top: 1em }
+		p { margin-top: 16px }
 		</pre>
 
 		<figure>
@@ -1347,7 +1350,7 @@ Pagination and overflow outside multicol containers</h3>
 
 	<div class="example">
 		In fragmented contexts, the overflow content goes into columns in subsequent fragments.
-		Given the same content as in the previous example
+		Given the same content as in example 31
 		and a page box that only has room for five lines of formatted text,
 		this would appear on the first page: