diff --git a/src/SimpleXLSXGen.php b/src/SimpleXLSXGen.php
index 2d9a4cd..1c7b065 100644
--- a/src/SimpleXLSXGen.php
+++ b/src/SimpleXLSXGen.php
@@ -499,7 +499,7 @@ class SimpleXLSXGen
                                 $ba[] = $ba[0];
                             }
                             if (!isset($ba[4])) { // diagonal
-                                 $ba[] = 'none';
+                                $ba[] = 'none';
                             }
                             $sides = ['left' => 3, 'right' => 1, 'top' => 0, 'bottom' => 2, 'diagonal' => 4];
                             foreach ($sides as $side => $idx) {