See the linked test case. The relevant spec text: http://dev.w3.org/csswg/css-style-attr/#syntax
(updated link)
Safari pass this test now - https://wpt.fyi/results/css/css-style-attr/style-attr-braces-001.xht?label=experimental&label=master&aligned Can this be marked as "RESOLVED CONFIGURATION CHANGED". Thanks!
Yup, passing now.