diff --git a/css-animations-1/Overview.bs b/css-animations-1/Overview.bs
index 7fb241b9188..dc0c56902ec 100644
--- a/css-animations-1/Overview.bs
+++ b/css-animations-1/Overview.bs
@@ -1052,7 +1052,7 @@ IDL Definition</h4>
 	[Exposed=Window]
 	interface CSSKeyframeRule : CSSRule {
 	  attribute CSSOMString keyText;
-	  [SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+	  [SameObject, PutForwards=cssText] readonly attribute CSSStyleProperties style;
 	};
 	</pre>
 
@@ -1074,7 +1074,7 @@ Attributes</h4>
 
 		<dt><dfn>style</dfn>
 		<dd>
-			Must return a {{CSSStyleDeclaration}} object for the
+			Must return a {{CSSStyleProperties}} object for the
 			keyframe rule, with the following properties:
 
 			<dl>
diff --git a/css-fonts-4/Overview.bs b/css-fonts-4/Overview.bs
index 95bcbad87f6..7f34853d5aa 100644
--- a/css-fonts-4/Overview.bs
+++ b/css-fonts-4/Overview.bs
@@ -8224,9 +8224,39 @@ The <code id="cssfontfacerule2">CSSFontFaceRule</code> interface</h3>
 The <dfn id="cssfontfacerule-interface">CSSFontFaceRule</dfn> interface represents a <<@font-face>> rule.
 
 <pre class="idl">
+[Exposed=Window]
+interface CSSFontFaceDescriptors : CSSStyleDeclaration {
+	attribute [LegacyNullToEmptyString] CSSOMString src;
+	attribute [LegacyNullToEmptyString] CSSOMString fontFamily;
+	attribute [LegacyNullToEmptyString] CSSOMString font-family;
+	attribute [LegacyNullToEmptyString] CSSOMString fontStyle;
+	attribute [LegacyNullToEmptyString] CSSOMString font-style;
+	attribute [LegacyNullToEmptyString] CSSOMString fontWeight;
+	attribute [LegacyNullToEmptyString] CSSOMString fontStretch;
+	attribute [LegacyNullToEmptyString] CSSOMString font-stretch;
+	attribute [LegacyNullToEmptyString] CSSOMString unicodeRange;
+	attribute [LegacyNullToEmptyString] CSSOMString unicode-range;
+	attribute [LegacyNullToEmptyString] CSSOMString fontFeatureSettings;
+	attribute [LegacyNullToEmptyString] CSSOMString font-feature-settings;
+	attribute [LegacyNullToEmptyString] CSSOMString fontVariationSettings;
+	attribute [LegacyNullToEmptyString] CSSOMString font-variation-settings;
+	attribute [LegacyNullToEmptyString] CSSOMString fontNamedInstance;
+	attribute [LegacyNullToEmptyString] CSSOMString font-named-instance;
+	attribute [LegacyNullToEmptyString] CSSOMString fontDisplay;
+	attribute [LegacyNullToEmptyString] CSSOMString font-display;
+	attribute [LegacyNullToEmptyString] CSSOMString fontLanguageOverride;
+	attribute [LegacyNullToEmptyString] CSSOMString font-language-override;
+	attribute [LegacyNullToEmptyString] CSSOMString ascentOverride;
+	attribute [LegacyNullToEmptyString] CSSOMString ascent-override;
+	attribute [LegacyNullToEmptyString] CSSOMString descentOverride;
+	attribute [LegacyNullToEmptyString] CSSOMString descent-override;
+	attribute [LegacyNullToEmptyString] CSSOMString lineGapOverride;
+	attribute [LegacyNullToEmptyString] CSSOMString line-gap-override;
+};
+
 [Exposed=Window]
 interface CSSFontFaceRule : CSSRule {
-	readonly attribute CSSStyleDeclaration style;
+	readonly attribute CSSFontFaceDescriptors style;
 };
 </pre>
 
diff --git a/cssom-1/Overview.bs b/cssom-1/Overview.bs
index de209b309f8..0a5bb80a0b1 100644
--- a/cssom-1/Overview.bs
+++ b/cssom-1/Overview.bs
@@ -2000,7 +2000,7 @@ The <code>CSSStyleRule</code> interface represents a style rule.
 [Exposed=Window]
 interface CSSStyleRule : CSSGroupingRule {
   attribute CSSOMString selectorText;
-  [SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+  [SameObject, PutForwards=cssText] readonly attribute CSSStyleProperties style;
 };
 </pre>
 
@@ -2013,11 +2013,13 @@ On setting the {{CSSStyleRule/selectorText}} attribute these steps must be run:
  <li>Otherwise, if the algorithm returns a null value, do nothing.
 </ol>
 
-The <dfn attribute for=CSSStyleRule>style</dfn> attribute must return a <code>CSSStyleDeclaration</code> object for the style rule, with the
+The <dfn attribute for=CSSStyleRule>style</dfn> attribute must return a <code>CSSStyleProperties</code> object for the style rule, with the
 following properties:
 <dl>
  <dt><a for="CSSStyleDeclaration">computed flag</a>
  <dd>Unset.
+ <dt><a for="CSSStyleDeclaration">readonly flag</a>
+ <dd>Unset.
  <dt><a for="CSSStyleDeclaration">declarations</a>
  <dd>The declared declarations in the rule, in <a>specified order</a>.
  <dt><a for="CSSStyleDeclaration">parent CSS rule</a>
@@ -2106,14 +2108,30 @@ Issue: Need to define the rules for
 <dfn export>serialize a list of CSS page selectors</dfn>.
 
 <pre class=idl>
+[Exposed=Window]
+interface CSSPageDescriptors : CSSStyleDeclaration {
+  attribute [LegacyNullToEmptyString] CSSOMString margin;
+  attribute [LegacyNullToEmptyString] CSSOMString marginTop;
+  attribute [LegacyNullToEmptyString] CSSOMString marginRight;
+  attribute [LegacyNullToEmptyString] CSSOMString marginBottom;
+  attribute [LegacyNullToEmptyString] CSSOMString marginLeft;
+  attribute [LegacyNullToEmptyString] CSSOMString margin-top;
+  attribute [LegacyNullToEmptyString] CSSOMString margin-right;
+  attribute [LegacyNullToEmptyString] CSSOMString margin-bottom;
+  attribute [LegacyNullToEmptyString] CSSOMString margin-left;
+  attribute [LegacyNullToEmptyString] CSSOMString size;
+  attribute [LegacyNullToEmptyString] CSSOMString marks;
+  attribute [LegacyNullToEmptyString] CSSOMString bleed;
+};
+
 [Exposed=Window]
 interface CSSPageRule : CSSGroupingRule {
            attribute CSSOMString selectorText;
-  [SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+  [SameObject, PutForwards=cssText] readonly attribute CSSPageDescriptors style;
 };
 </pre>
 
-The <dfn attribute for=CSSGroupingRule>selectorText</dfn> attribute, on getting, must return the result of
+The <dfn attribute for=CSSPageRule>selectorText</dfn> attribute, on getting, must return the result of
 <a lt="serialize a list of CSS page selectors">serializing</a> the associated <a>list of CSS page selectors</a>.
 On setting the {{CSSPageRule/selectorText}} attribute  these steps must be run:
 <ol>
@@ -2122,13 +2140,15 @@ On setting the {{CSSPageRule/selectorText}} attribute  these steps must be run:
  <li>Otherwise, if the algorithm returns a null value, do nothing.
 </ol>
 
-The <dfn attribute for=CSSGroupingRule>style</dfn> attribute must return a <code>CSSStyleDeclaration</code> object for the
+The <dfn attribute for=CSSPageRule>style</dfn> attribute must return a <code>CSSPageDescriptors</code> object for the
 <code>@page</code> at-rule, with the following properties:
 <dl>
  <dt><a for="CSSStyleDeclaration">computed flag</a>
  <dd>Unset.
+ <dt><a for="CSSStyleDeclaration">readonly flag</a>
+ <dd>Unset.
  <dt><a for="CSSStyleDeclaration">declarations</a>
- <dd>The declared declarations in the rule, in <a>specified order</a>.
+ <dd>The declared descriptors in the rule, in <a>specified order</a>.
  <dt><a for="CSSStyleDeclaration">parent CSS rule</a>
  <dd>The <a>context object</a>.
  <dt><a for="CSSStyleDeclaration">owner node</a>
@@ -2145,18 +2165,20 @@ The <code>CSSMarginRule</code> interface represents a margin at-rule (e.g. <code
 [Exposed=Window]
 interface CSSMarginRule : CSSRule {
   readonly attribute CSSOMString name;
-  [SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+  [SameObject, PutForwards=cssText] readonly attribute CSSMarginDescriptors style;
 };
 </pre>
 
 The <dfn attribute for=CSSMarginRule>name</dfn> attribute must return the name of the margin at-rule. The <code>@</code> character is not
 included in the name. [[!CSS3SYN]]
 
-The <dfn attribute for=CSSMarginRule>style</dfn> attribute must return a <code>CSSStyleDeclaration</code> object for the
+The <dfn attribute for=CSSMarginRule>style</dfn> attribute must return a <code>CSSMarginDescriptors</code> object for the
 margin at-rule, with the following properties:
 <dl>
  <dt><a for="CSSStyleDeclaration">computed flag</a>
  <dd>Unset.
+ <dt><a for="CSSStyleDeclaration">readonly flag</a>
+ <dd>Unset.
  <dt><a for="CSSStyleDeclaration">declarations</a>
  <dd>The declared declarations in the rule, in <a>specified order</a>.
  <dt><a for="CSSStyleDeclaration">parent CSS rule</a>
@@ -2217,6 +2239,9 @@ the DOM a <a>CSS declaration block</a> is a
  <dd>Set if the object is a computed style declaration, rather than a specified
      style. Unless otherwise stated it is unset.
 
+ <dt><dfn>readonly flag</dfn>
+ <dd>Set if the object is not modifiable.</dd>
+
  <dt><dfn>declarations</dfn>
  <dd>The <a>CSS declarations</a> associated with the object.
 
@@ -2373,6 +2398,10 @@ interface CSSStyleDeclaration {
   [CEReactions] undefined setProperty(CSSOMString property, [LegacyNullToEmptyString] CSSOMString value, optional [LegacyNullToEmptyString] CSSOMString priority = "");
   [CEReactions] CSSOMString removeProperty(CSSOMString property);
   readonly attribute CSSRule? parentRule;
+};
+
+[Exposed=Window]
+interface CSSStyleProperties : CSSStyleDeclaration {
   [CEReactions] attribute [LegacyNullToEmptyString] CSSOMString cssFloat;
 };
 </pre>
@@ -2388,7 +2417,7 @@ Getting the <dfn attribute for="CSSStyleDeclaration">cssText</dfn> attribute mus
 
 Setting the {{CSSStyleDeclaration/cssText}} attribute must run these steps:
 <ol>
- <li>If the <a for="CSSStyleDeclaration">computed flag</a> is set,
+ <li>If the <a for="CSSStyleDeclaration">readonly flag</a> is set,
  then <a>throw</a> a {{NoModificationAllowedError}} exception.
  <li>Empty the <a for="CSSStyleDeclaration">declarations</a>.
  <li><a lt="Parse a CSS declaration block">Parse</a> the given value and, if the return value is not the empty list, insert the items in the list
@@ -2454,7 +2483,7 @@ value would be "<code>important</code>".</div>
 
 The <dfn method for=CSSStyleDeclaration>setProperty(<var>property</var>, <var>value</var>, <var>priority</var>)</dfn> method must run these steps:
 <ol>
- <li>If the <a for="CSSStyleDeclaration">computed flag</a> is set,
+ <li>If the <a for="CSSStyleDeclaration">readonly flag</a> is set,
  then <a>throw</a> a {{NoModificationAllowedError}} exception.
  <li>If <var>property</var> is not a <a>custom property</a>, follow these substeps:
   <ol>
@@ -2569,7 +2598,7 @@ use different algorithms as long as the constraints above hold.
 
 The <dfn method for=CSSStyleDeclaration>removeProperty(<var>property</var>)</dfn> method must run these steps:
 <ol>
- <li>If the <a for="CSSStyleDeclaration">computed flag</a> is set,
+ <li>If the <a for="CSSStyleDeclaration">readonly flag</a> is set,
  then <a>throw</a> a {{NoModificationAllowedError}} exception.
  <li>If <var>property</var> is not a <a>custom property</a>,
  let <var>property</var> be <var>property</var> <a lt="ASCII lowercase">converted to ASCII lowercase</a>.
@@ -2592,7 +2621,7 @@ The <dfn method for=CSSStyleDeclaration>removeProperty(<var>property</var>)</dfn
 The <dfn attribute for=CSSStyleDeclaration>parentRule</dfn> attribute must return the
 <a for="CSSStyleDeclaration">parent CSS rule</a>.
 
-The <dfn attribute for=CSSStyleDeclaration>cssFloat</dfn>
+The <dfn attribute for=CSSStyleProperties>cssFloat</dfn>
 attribute, on getting, must return the result of invoking
 {{CSSStyleDeclaration/getPropertyValue()}} with
 <code>float</code> as argument. On setting, the attribute must invoke
@@ -2606,17 +2635,17 @@ is obtained by running the <a>CSS property to IDL attribute</a> algorithm for
 <var>property</var>.
 
 <pre class="idl extract">
-partial interface CSSStyleDeclaration {
+partial interface CSSStyleProperties {
   [CEReactions] attribute [LegacyNullToEmptyString] CSSOMString _<var>camel_cased_attribute</var>;
 };
 </pre>
 
-The <a attribute for=CSSStyleDeclaration><var>camel-cased attribute</var></a> attribute, on getting, must return the
+The <a attribute for=CSSStyleProperties><var>camel-cased attribute</var></a> attribute, on getting, must return the
 result of invoking {{CSSStyleDeclaration/getPropertyValue()}} with the
 argument being the result of running the <a>IDL attribute to CSS property</a>
 algorithm for <var>camel-cased attribute</var>.
 
-Setting the <a attribute for=CSSStyleDeclaration><var>camel-cased attribute</var></a> attribute must invoke
+Setting the <a attribute for=CSSStyleProperties><var>camel-cased attribute</var></a> attribute must invoke
 {{CSSStyleDeclaration/setProperty()}} with the
 first argument being the result of running the <a>IDL attribute to CSS property</a>
 algorithm for <var>camel-cased attribute</var>, as second argument the given value, and no third argument. Any
@@ -2630,12 +2659,12 @@ with the string <code>-webkit-</code>, the following partial interface applies w
 algorithm for <var>property</var>, with the <i>lowercase first</i> flag set.
 
 <pre class="idl extract">
-partial interface CSSStyleDeclaration {
+partial interface CSSStyleProperties {
   [CEReactions] attribute [LegacyNullToEmptyString] CSSOMString _<var>webkit_cased_attribute</var>;
 };
 </pre>
 
-The <dfn attribute for=CSSStyleDeclaration><var>webkit-cased attribute</var></dfn> attribute, on
+The <dfn attribute for=CSSStyleProperties><var>webkit-cased attribute</var></dfn> attribute, on
 getting, must return the result of invoking {{CSSStyleDeclaration/getPropertyValue()}} with the
 argument being the result of running the <a>IDL attribute to CSS property</a> algorithm for
 <var>webkit-cased attribute</var>, with the <i>dash prefix</i> flag set.
@@ -2655,16 +2684,16 @@ except for properties that have no "<code>-</code>" (U+002D) in the property nam
 the following partial interface applies where <var>dashed attribute</var> is <var>property</var>.
 
 <pre class="idl extract">
-partial interface CSSStyleDeclaration {
+partial interface CSSStyleProperties {
   [CEReactions] attribute [LegacyNullToEmptyString] CSSOMString _<var>dashed_attribute</var>;
 };
 </pre>
 
-The <dfn attribute for=CSSStyleDeclaration><var>dashed attribute</var></dfn> attribute, on getting, must return the
+The <dfn attribute for=CSSStyleProperties><var>dashed attribute</var></dfn> attribute, on getting, must return the
 result of invoking {{CSSStyleDeclaration/getPropertyValue()}} with the
 argument being <var>dashed attribute</var>.
 
-Setting the <a attribute for=CSSStyleDeclaration><var>dashed attribute</var></a> attribute must invoke
+Setting the <a attribute for=CSSStyleProperties><var>dashed attribute</var></a> attribute must invoke
 {{CSSStyleDeclaration/setProperty()}} with the
 first argument being <var>dashed attribute</var>, as second argument the given value, and no third argument. Any
 exceptions thrown must be re-thrown.
@@ -2976,7 +3005,7 @@ interface mixin ElementCSSInlineStyle {
 </pre>
 
 The <dfn attribute for=ElementCSSInlineStyle>style</dfn> attribute must return a <a>CSS declaration block</a> object whose
-<a for="CSSStyleDeclaration">computed flag</a> is unset, whose <a for="CSSStyleDeclaration">parent CSS rule</a> is null, and
+<a for="CSSStyleDeclaration">readonly flag</a> is unset, whose <a for="CSSStyleDeclaration">parent CSS rule</a> is null, and
 whose <a for="CSSStyleDeclaration">owner node</a> is the <a>context object</a>.
 
 If the user agent supports HTML, the following IDL applies: [[HTML]]
@@ -3043,10 +3072,12 @@ steps:
   <a href="https://github.com/w3c/csswg-drafts/issues/4947">#4947</a>.
 
  <li>
-  Return a live <a>CSS declaration block</a> with the following properties:
+  Return a live <a>CSSStyleProperties</a> object with the following properties:
   <dl>
    <dt><a for="CSSStyleDeclaration">computed flag</a>
    <dd>Set.
+   <dt><a for="CSSStyleDeclaration">readonly flag</a>
+   <dd>Set.
    <dt><a for="CSSStyleDeclaration">declarations</a>
    <dd><var>decls</var>.
    <dt><a for="CSSStyleDeclaration">parent CSS rule</a>
@@ -3054,7 +3085,6 @@ steps:
    <dt><a for="CSSStyleDeclaration">owner node</a>
    <dd><var>obj</var>.
   </dl>
-
 </ol>
 
 <p class=warning>The {{Window/getComputedStyle()}} method exposes information from <a lt="CSS style sheet">CSS style