From d9005e29718dd0b5bfb3709a72bc5f8f18cf589c Mon Sep 17 00:00:00 2001
From: Kevin Babbitt
Date: Thu, 11 Dec 2025 12:20:13 -0800
Subject: [PATCH] [css-borders-4] Adjust border-width zero value special case
per WG resolution. #11494
---
css-borders-4/Overview.bs | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/css-borders-4/Overview.bs b/css-borders-4/Overview.bs
index 90edd1404c5a..f561c317f51f 100644
--- a/css-borders-4/Overview.bs
+++ b/css-borders-4/Overview.bs
@@ -370,7 +370,7 @@ Line Thickness: the 'border-width' properties
Inherited: no
Logical property group: border-width
Percentages: N/A
- Computed value: absolute length, [=snapped as a border width=]; zero if the border style is ''border-style/none'' or ''border-style/hidden''
+ Computed value: absolute length, [=snapped as a border width=]
Animation Type: by computed value
@@ -385,6 +385,11 @@ Line Thickness: the 'border-width' properties
The thin, medium, and thick keywords
are equivalent to ''1px'', ''3px'', and ''5px'', respectively.
+ The [=resolved value=] for the 'border-width' properties is the [=used value=].
+
+ If the 'border-style' corresponding to a given 'border-width' is ''border-style/none'' or ''border-style/hidden'',
+ then the [=used value|used=] width is 0.
+
The [=flow-relative=] properties
'border-block-start-width',
'border-block-end-width',
@@ -3239,6 +3244,9 @@ First Public Working Draft of 22 July 2025
* Renamed normal value of 'border-*-clip' properties to ''border-top-clip/none''
* Added new syntax for 'border-*-*-radius' longhands using a slash to separate horizontal and vertical radii
* Allowed a single <> value for 'box-shadow-offset' to set both offsets to the same value
+ * Changed the special case of 'border-width' having a value of ''0'' when 'border-style' is ''border-style/none'' or ''border-style/hidden''
+ from a computed-value effect to a resolved-value effect.
+ (Issue 11494)
Additions since [[CSS3BG]]