fix detection of dark mode on MacOS

Author: umbynos

icon/icondarwin.go

@@ -9,10 +9,15 @@ import (
 )
 
 // IsDarkMode will return if the system is in darkmode
+// see https://gist.github.com/jerblack/869a303d1a604171bf8f00bbbefa59c2
 func IsDarkMode() bool {
 	cmd := exec.Command("defaults", "read", "-g", "AppleInterfaceStyle")
-	output, _ := cmd.Output()
-	return strings.Contains(string(output), "Dark")
+	if err := cmd.Run(); err != nil {
+		if _, ok := err.(*exec.ExitError); ok {
+			return false
+		}
+	}
+	return true
 }
 
 // GetIcon will return the icon