From f21d3262d1aa7ba548107aa7967fbbc92020dfd4 Mon Sep 17 00:00:00 2001
From: Anders Hartvoll Ruud <andruud@gmail.com>
Date: Thu, 8 Nov 2018 09:42:58 +0100
Subject: [PATCH] [css-properties-values-api] Require var() fallbacks to match
 syntax.

Resolves #360.
---
 css-properties-values-api/Overview.bs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/css-properties-values-api/Overview.bs b/css-properties-values-api/Overview.bs
index ceb3d2de..67cdd395 100644
--- a/css-properties-values-api/Overview.bs
+++ b/css-properties-values-api/Overview.bs
@@ -589,6 +589,18 @@ to full URLs as described in [[!css3-values]].
 
 </div>
 
+
+Fallbacks in ''var()'' references {#fallbacks-in-var-references}
+----------------------------------------------------------------
+
+References to registered custom properties using the ''var()'' function may
+provide a fallback. However, the fallback value must match the
+[[#supported-syntax-strings|registered syntax]] of the custom property being
+referenced, otherwise the declaration is
+<a spec=css-variables>invalid at computed-value time</a>.
+
+Note: This applies regardless of whether or not the fallback is being used.
+
 Examples {#examples}
 ====================