[mediaqueries-5] Make bikeshed happy and clarify status

Author: frivoal

mediaqueries-5/Overview.bs

@@ -1,19 +1,18 @@
 <pre class='metadata'>
 Title: Media Queries Level 5
 Group: csswg
-Shortname: mediaqueries
+Shortname: mediaqueries-5
 Level: 5
 Status: ED
+Status Text: Once complete, this specification will include and extend <cite>Media Queries Level&nbsp;4.</cite> [[MEDIAQUERIES-4]]
 Work Status: Exploring
 ED: https://drafts.csswg.org/mediaqueries-5/
 TR:
 Previous Version:
 Editor: Dean Jackson, Apple
-Editor: Florian Rivoal, Vivliostyle, http://florian.rivoal.net, http://vivliostyle.com, w3cid 43241
+Editor: Florian Rivoal, Vivliostyle, https://florian.rivoal.net, http://vivliostyle.com, w3cid 43241
 Editor: Tab Atkins Jr., Google, http://xanthir.com/contact/, w3cid 42199
 Abstract: <a>Media Queries</a> allow authors to test and query values or features of the user agent or display device, independent of the document being rendered.  They are used in the CSS @media rule to conditionally apply styles to a document, and in various other contexts and languages, such as HTML and Javascript.
-Abstract:
-Abstract: Media Queries Level 5 describes the mechanism and syntax of media queries, media types, and media features. It extends and supersedes the features defined in Media Queries Level 4.
 Ignored Terms: min-resolution, max-resolution, none, view-mode, mediaText, DOMString
 Link Defaults: css-break-3 (property) break-inside
 Link Defaults: css-cascade-3 (at-rule) @import
@@ -23,6 +22,17 @@ Link Defaults: css-cascade-3 (at-rule) @import
 spec:css-values-3; type:value; text:in
 </pre>
 
+<h2 id="intro">
+Introduction</h2>
+
+Note: At the time of writing, [[MEDIAQUERIES-4]] is not completely finalized yet.
+To avoid accidental divergences and maintenance overhead,
+This specification is written as a delta specification over Media Queries Level 4.
+Once the level 4 specification is final,
+its content will be integrated into this specification,
+which will then replace it.
+Until then, Media Queries Level 5 only contains additions and extensions to level 4.
+
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@@ -172,7 +182,7 @@ Custom Media Queries</h2>
 	Note: For error handling purposes,
 	an undefined <a>media feature</a> is different from
 	a <a>media feature</a> that evaluates to false.
-	See <a href="#error-handling">Error Handling</a> for details.
+	See [[mediaqueries-4#error-handling]] for details.
 
 	<div class='example'>
 		For example, if a responsive site uses a particular breakpoint in several places,