diff --git a/src/components/themr.js b/src/components/themr.js
index aaa4d8c..750dbab 100644
--- a/src/components/themr.js
+++ b/src/components/themr.js
@@ -89,7 +89,7 @@ function themeable(style = {}, theme) {
        style[key] && theme[key].indexOf(style[key]) === -1
        ? `${style[key]} ${theme[key]}`
        : theme[key] || style[key]
-    })), style)
+    })), Object.assign({}, style))
 }
 
 function validateComposeOption(composeTheme) {