diff --git a/ui/style/style_core_font.h b/ui/style/style_core_font.h
index e0c85aa..152357b 100644
--- a/ui/style/style_core_font.h
+++ b/ui/style/style_core_font.h
@@ -11,6 +11,8 @@
 #include <QtGui/QFont>
 #include <QtGui/QFontMetrics>
 
+#include <cmath>
+
 namespace style {
 namespace internal {