From 9392d400e383c8cef8ccc7484174b201950a3b62 Mon Sep 17 00:00:00 2001
From: Luke Warlow <lwarlow@igalia.com>
Date: Thu, 26 Feb 2026 10:45:23 +0000
Subject: [PATCH] [css-forms-1] Add checkmark content for indeterminate
 checkboxes

---
 css-forms-1/Overview.bs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/css-forms-1/Overview.bs b/css-forms-1/Overview.bs
index 69676625a695..57e748cd406f 100644
--- a/css-forms-1/Overview.bs
+++ b/css-forms-1/Overview.bs
@@ -894,11 +894,15 @@ input[type=radio]::checkmark {
     content: '';
 }
 
-input[type=checkbox]:not([switch], :checked)::checkmark {
+input[type=checkbox]:not([switch], :checked, :indeterminate)::checkmark {
 input[type=radio]:not(:checked)::checkmark {
     visibility: hidden;
 }
 
+input[type=checkbox]:indeterminate::checkmark {
+    content: '\2500' / '';
+}
+
 input[type=radio] {
     border-radius: 50%;
 }