diff --git a/src/compiler/compile/css/Stylesheet.ts b/src/compiler/compile/css/Stylesheet.ts
index 7f0c0b52ca..0a3098db6d 100644
--- a/src/compiler/compile/css/Stylesheet.ts
+++ b/src/compiler/compile/css/Stylesheet.ts
@@ -145,6 +145,8 @@ class Declaration {
 			? this.node.value.children[0]
 			: this.node.value;
 
+		// Don't minify whitespace in custom properties, since some browsers (Chromium < 99)
+		// treat --foo: ; and --foo:; differently
 		if (first.type === 'Raw' && /^\s+$/.test(first.value)) return;
 
 		let start = first.start;