diff --git a/css-properties-values-api/Overview.bs b/css-properties-values-api/Overview.bs
index dc568075..8e4bc909 100644
--- a/css-properties-values-api/Overview.bs
+++ b/css-properties-values-api/Overview.bs
@@ -711,21 +711,10 @@ Conditional Rules {#conditional-rules}
--------------------------------------
- ''@supports'' rules and the {{CSS/supports(conditionText)}} method
+ ''@supports'' rules and the {{CSS/supports()}} method
behave as specified in [[!css-variables]],
without distinguishing between registered and unregistered custom properties,
and paying no attention to registered properties' syntaxes.
-
- {{CSS/supports(property, value)}},
- as specified in [[css-conditional-1]],
- does pay attention to the syntax of registered custom properties.
-
- The general principle in use
- is that anything which evaluates the validity of a CSS property value on its own
- will pay attention to the syntax of registered custom properties,
- but anything parsing any larger construct
- (such as declarations, or entire stylesheets)
- will ignore the syntax.
Relative URLs {#relative-urls}
@@ -820,57 +809,12 @@ string.
CSSOM {#cssom}
==============
-{{CSSStyleDeclaration}} Behavior {#css-style-declaration-behavior}
-------------------------------------------------------------------
-
-The set a CSS declaration algorithm gains an additional constraint
-for registered custom properties:
-
-* The target declaration must have a value that matches the registered
- [=syntax descriptor|syntax=] of the property.
-
-This means that once a property is registered, it is not possible to use
-{{setProperty()}} with a value that violates the registered syntax of the
-property.
-
-Note: Registering a property with a particular syntax
-does not invalidate already-specified values for the property
-(that is, they're not thrown out at parse-time,
-like invalid properties usually are),
-even if those would violate the registered syntax.
-The registration does prevent new invalid values from being set,
-and affects how the custom property calculates its [=computed value=].
-
-
- For example,
- in the following code snippet,
- the ''--x'' property is set to a value
- that doesn't match the later-registered syntax:
-
-
- document.body.style.setProperty('--x', '10px');
- CSS.registerProperty({
- name: '--x',
- syntax: '<color>',
- initialValue: 'white',
- inherits: false
- });
-
- // This still outputs "10px", as existing values aren't
- // re-evaluated after a syntax is registered.
- console.log(document.body.style.getPropertyValue('--x'));
-
- // This silently fails, like any other property would
- // when one attempts to set it to an invalid value.
- document.body.style.setProperty('--x', '20px');
-
- // Because ''--x'' is still set to "10px", which isn't
- // a valid <>, it will be "[=invalid at computed-value time=]",
- // falling back to the registered initial value of "white".
- // 'background-color' will then receive that color and get
- // set to "white".
- document.body.style.backgroundColor = "var(--x)";
-
+
+ The value specified for a registered custom property is not
+ interpreted until computed-value time. This means that only APIs that
+ retrieve computed values are affected. Other APIs must ignore the
+ {{[[registeredPropertySet]]}} slot of the associated {{Document}}, and
+ treat all custom properties as unregistered.
{{CSSStyleValue}} Reification {#css-style-value-reification}
@@ -880,14 +824,8 @@ and affects how the custom property calculates its [=computed value=].
To
reify a registered custom property value given a property
|property| and [=syntax descriptor=] |syntax|, run these steps:
- For specified values:
-
- 1. If the value is a <
>, and |syntax| is not the
- [=universal syntax descriptor=], attempt to [=CSS/parse=]
- the value according to |syntax|. If this succeeds, [=reify=]
- the result as if it were a computed value, and return that result.
- 2. Otherwise, [=reify a list of component values=] from the value, and
- return the result.
+ For specified values, [=reify a list of component values=] from the value,
+ and return the result.
For computed values: