To add the same “current page” styling to your mega menu triggers as you have for normal pages, add the addActiveTriggerClass option to the settings in your Site Footer Code Injection area. This will add the same active styling when any link within the mega menu is the current page.

DO NOT add this entire code block again, simply add line 5 to what you already have. 

<script>
  window.wmMegaMenuSettings = {
    layout: 'full-width', // full-width or inset
    openAnimation: 'slide', // slide, fade, or swing
    addActiveTriggerClass: true,
  }
</script>
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Add "Active" Styling to Links in Mega Menu