[css-2020] Improve module descriptions.

Author: fantasai

css-2020/Overview.bs

@@ -147,16 +147,16 @@ Classification of CSS Specifications</h2>
 		<dt><a href="https://www.w3.org/TR/CSS2/">CSS Level 2, latest revision</a> (including errata)
 		  [[!CSS2]]
 		<dd>
-				This defines the core of CSS, parts of which are overridden by later specifications.
-				We recommend in particular reading <a href="https://www.w3.org/TR/CSS2/intro.html">Chapter 2</a>,
-				which introduces some of the basic concepts of CSS
-				and its design principles.
+			This defines the core of CSS, parts of which are overridden by later specifications.
+			We recommend in particular reading <a href="https://www.w3.org/TR/CSS2/intro.html">Chapter 2</a>,
+			which introduces some of the basic concepts of CSS
+			and its design principles.
 
 		<dt><a href="https://www.w3.org/TR/css-syntax-3/">CSS Syntax Level 3</a>
 		  [[!CSS-SYNTAX-3]]
 		<dd>
 			Replaces CSS2&sect;4.1, CSS2&sect;4.2, CSS2&sect;4.4, and CSS2&sect;G,
-			defining how CSS is parsed.
+			redefining how CSS is parsed.
 
 		<dt><a href="https://www.w3.org/TR/css-style-attr/">CSS Style Attributes</a>
 		  [[!CSS-STYLE-ATTR]]
@@ -171,8 +171,9 @@ Classification of CSS Specifications</h2>
 		<dt><a href="https://www.w3.org/TR/css-conditional-1/">CSS Conditional Rules Level 3</a>
 		  [[!CSS-CONDITIONAL-1]]
 		<dd>
-			Replaces CSS2&sect;7.2, updating the definition of ''@media'' rules to allow nesting,
-			and introduces ''@supports'' rules for feature-support queries.
+			Extends and supersedes CSS2&sect;7.2,
+			updating the definition of ''@media'' rules to allow nesting
+			and introducing the ''@supports'' rule for feature-support queries.
 
 		<dt><a href="https://www.w3.org/TR/css-selectors-3/">Selectors Level 3</a>
 		  [[!SELECTORS-3]]
@@ -187,14 +188,14 @@ Classification of CSS Specifications</h2>
 		<dt><a href="https://www.w3.org/TR/css-cascade-4/">CSS Cascading and Inheritance Level 4</a>
 		  [[!CSS-CASCADE-4]]
 		<dd>
-			Replaces CSS2&sect;1.4.3 and CSS2&sect;6, as well as [[CSS-CASCADE-3]].
+			Extends and supersedes CSS2&sect;1.4.3 and CSS2&sect;6, as well as [[CSS-CASCADE-3]].
 			Describes how to collate style rules and assign values to all properties on all elements.
 			By way of cascading and inheritance, values are propagated for all properties on all elements.
 
 		<dt><a href="https://www.w3.org/TR/css-values-3/">CSS Values and Units Level 3</a>
 		  [[!CSS-VALUES-3]]
 		<dd>
-			Replaces CSS2&sect;1.4.2.1, CSS2&sect;4.3, and CSS2&sect;A.2.1&ndash;3,
+			Extends and supersedes CSS2&sect;1.4.2.1, CSS2&sect;4.3, and CSS2&sect;A.2.1&ndash;3,
 			defining CSS's property definition syntax
 			and expanding its set of units.
 
@@ -212,30 +213,30 @@ Classification of CSS Specifications</h2>
 		<dt><a href="https://www.w3.org/TR/css-color-3/">CSS Color Level 3</a>
 		  [[!CSS-COLOR-3]]
 		<dd>
-			Replaces CSS2&sect;4.3.6, CSS2&sect;14.1, and CSS2&sect;18.2,
-			defining an extended range of color values.
+			Extends and supersedes CSS2&sect;4.3.6, CSS2&sect;14.1, and CSS2&sect;18.2,
+			introducing an extended range of color values.
 			Also introduces the 'opacity' property.
 
 		<dt><a href="https://www.w3.org/TR/css-backgrounds-3/">CSS Backgrounds and Borders Level 3</a>
 		  [[!CSS-BACKGROUNDS-3]]
 		<dd>
-			Replaces CSS2&sect;8.5 and CSS2&sect;14.2,
+			Extends and supersedes CSS2&sect;8.5 and CSS2&sect;14.2,
 			providing more control of backgrounds and borders,
 			including layered background images,
 			image borders,
 			and drop shadows.
 
-		<dt><a href="https://www.w3.org/TR/css-images-3/">CSS Image Values and Replaced Content Level 3</a>
+		<dt><a href="https://www.w3.org/TR/css-images-3/">CSS Images Level 3</a>
 		  [[!CSS-IMAGES-3]]
 		<dd>
-			Provides a new foundation text for the sizing of replaced elements (such as images),
-			adds additional controls to their sizing and orientation,
-			and introduces syntax for gradients as images in CSS.
+			Redefines and incorporates the external 2D image value type,
+			introduces native 2D gradients,
+			and adds additional controls for replaced element sizing and rendering.
 
 		<dt><a href="https://www.w3.org/TR/css-fonts-3/">CSS Fonts Level 3</a>
 		  [[!CSS-FONTS-3]]
 		<dd>
-			Replaces CSS2&sect;15
+			Extends and supersedes CSS2&sect;15
 			and provides more control over font choice and feature selection.
 
 		<dt><a href="https://www.w3.org/TR/css-writing-modes-3/">CSS Writing Modes Level 3</a>
@@ -245,6 +246,7 @@ Classification of CSS Specifications</h2>
 			such as left-to-right (e.g. Latin or Indic),
 			right-to-left (e.g. Hebrew or Arabic),
 			bidirectional (e.g. mixed Latin and Arabic) and vertical (e.g. Asian scripts).
+			Replaces and extends CSS2&sect;8.6 and &sect;9.10.
 
 		<dt><a href="https://www.w3.org/TR/css-multicol-1/">CSS Multi-column Layout Level 1</a>
 		  [[!CSS-MULTICOL-1]]
@@ -259,20 +261,20 @@ Classification of CSS Specifications</h2>
 		<dt><a href="https://www.w3.org/TR/css-ui-3/">CSS User Interface Module Level 3</a>
 		  [[!CSS-UI-3]]
 		<dd>
-			Replaces CSS2&sect;18.1 and CSS2&sect;18.4,
+			Extends and supersedes CSS2&sect;18.1 and CSS2&sect;18.4,
 			defining 'cursor', 'outline', and several new CSS features that also enhance the user interface.
 
 		<dt><a href="https://www.w3.org/TR/css-contain-1/">CSS Containment Module Level 1</a>
 		  [[!CSS-CONTAIN-1]]
 		<dd>
-			Describes the 'contain' property,
-			which indicates that the element’s subtree is independent of the rest of the page.
-			This enables heavy optimizations by user agents when used well.
+			Introduces the 'contain' property,
+			which enforces the independent CSS processing of an element’s subtree
+			in order to enable heavy optimizations by user agents when used well.
 
 		<dt><a href="https://www.w3.org/TR/css-transforms-1/">CSS Transforms Level 1</a>
 		  [[!CSS-TRANSFORMS-1]]
 		<dd>
-			Introduces graphical transformations to CSS.
+			Introduces coordinate-based graphical transformations to CSS.
 
 		<dt><a href="https://www.w3.org/TR/compositing-1/">CSS Compositing and Blending Level 1</a>
 		  [[!COMPOSITING]]
@@ -303,15 +305,17 @@ Fairly Stable Modules with limited implementation experience</h3>
 		<dt><a href="https://www.w3.org/TR/mediaqueries-4/">Media Queries Level 4</a>
 		  [[MEDIAQUERIES-4]]
 		<dd>
-			Extends and supersedes [[CSS3-MEDIAQUERIES]], expanding the syntax, deprecating most media types,
+			Extends and supersedes [[CSS3-MEDIAQUERIES]],
+			expanding the syntax, deprecating most media types,
 			and introducing new media features.
 
 		<dt><a href="https://www.w3.org/TR/css-display-3/">CSS Display Module Level 3</a>
 		  [[CSS-DISPLAY-3]]
 		<dd>
-			Describes how the CSS formatting box tree is generated
+			Replaces CSS2&sect;9.1.2, &sect;9.2.1 (but not &sect;9.2.1.1), &sect;9.2.2 (but not &sect;9.2.2.1), &sect;9.2.3, and &sect;9.2.4 (and lays the foundations for replacing &sect;9.7),
+			defining how the CSS formatting box tree is generated
 			from the document element tree
-			and defines the display property that controls it.
+			and defining the 'display' property that controls it.
 
 		<dt><a href="https://www.w3.org/TR/css-writing-modes-4/">CSS Writing Modes Level 4</a>
 		  [[CSS-WRITING-MODES-4]]
@@ -331,30 +335,33 @@ Fairly Stable Modules with limited implementation experience</h3>
 		<dt><a href="https://www.w3.org/TR/css-break-3/">CSS Fragmentation Module Level 3</a>
 		  [[CSS-BREAK-3]]
 		<dd>
-			Describes the fragmentation model that partitions a flow into pages, columns, or regions.
+			Describes the fragmentation model that partitions a flow into pages, columns, or regions
+			and defines properties that control it.
+			Extends and supersedes CSS2&sect;13.3.
 
 		<dt><a href="https://www.w3.org/TR/css-align-3/">CSS Box Alignment Module Level 3</a>
 		  [[CSS-ALIGN-3]]
 		<dd>
-			Contains the features of CSS relating to the alignment of boxes
+			Introduces properties to control the alignment of boxes
 			within their containers in the various CSS box layout models:
 			block layout, table layout, flex layout, and grid layout.
 
 		<dt><a href="https://www.w3.org/TR/css-shapes-1/">CSS Shapes Module Level 1</a>
 		  [[CSS-SHAPES-1]]
 		<dd>
-			Extends floats to effect non-rectangular wrapping shapes.
+			Extends floats (CSS2&sect;9.5) to effect non-rectangular wrapping shapes.
 
 		<dt><a href="https://www.w3.org/TR/css-text-3/">CSS Text Module Level 3</a>
 		  [[CSS-TEXT-3]]
 		<dd>
-			Defines properties for text manipulation and specifies their processing model.
+			Extends and supersedes CSS2&sect;16 excepting &sect;16.2,
+			defining properties for text manipulation and specifying their processing model.
 			It covers line breaking, justification and alignment, white space handling, and text transformation.
 
 		<dt><a href="https://www.w3.org/TR/css-text-decor-3/">CSS Text Decoration Level 3</a>
 		  [[CSS-TEXT-DECOR-3]]
 		<dd>
-			Replaces CSS2&sect;16.3,
+			Extends and supersedes CSS2&sect;16.3,
 			providing more control over text decoration lines
 			and adding the ability to specify text emphasis marks
 			and text shadows.
@@ -397,12 +404,12 @@ Modules with Rough Interoperability</h3>
 		  and <a href="https://www.w3.org/TR/css-animations-1/">CSS Animations Level 1</a>
 		  [[CSS-ANIMATIONS-1]].
 		<dd>
-			Define mechanisms for transitioning the computed values of CSS properties over time.
+			Introduces mechanisms for transitioning the computed values of CSS properties over time.
 
 		<dt><a href="https://www.w3.org/TR/css-grid-1/">CSS Grid Layout Module Level 1</a>
 		  [[!CSS-GRID-1]]
 		<dd>
-			Defines a two-dimensional grid-based layout system,
+			Introduces a two-dimensional grid-based layout system,
 			optimized for user interface design.
 			In the grid layout model, the children of a grid container
 			can be positioned into arbitrary slots in a predefined flexible or fixed-size layout grid.
@@ -415,12 +422,12 @@ Modules with Rough Interoperability</h3>
 		<dt><a href="https://www.w3.org/TR/filter-effects-1/">Filter Effects Module Level 1</a>
 		  [[FILTER-EFFECTS-1]]
 		<dd>
-			Filter effects are a way of processing an element’s rendering before it is displayed in the document.
+			Introduces filter effects as a way of processing an element’s rendering before it is displayed in the document.
 
 		<dt><a href="https://www.w3.org/TR/css-font-loading/">CSS Font Loading Module Level 3</a>
 		  [[CSS-FONT-LOADING-3]]
 		<dd>
-			Describes events and interfaces used for dynamically loading font resources.
+			Introduces events and interfaces used for dynamically loading font resources.
 	</dl>
 
 <h3 id="css-levels">