Update _variables.scss

Default size of the default watermark set to 128x128.

Author: eligiomerino

css/_variables.scss

@@ -167,8 +167,8 @@ $unsupportedDesktopBrowserTextFontSize: 21px;
 /**
  * The size of the default watermark.
  */
-$watermarkWidth: 71px;
-$watermarkHeight: 32px;
+$watermarkWidth: 128px;
+$watermarkHeight: 128px;
 
 $welcomePageWatermarkWidth: 128px;
 $welcomePageWatermarkHeight: 128px;