Scrollspy2

   <nav id="navbar-example3" class="h-100 flex-column align-items-stretch pe-4 border-end">
     <nav class="nav nav-pills flex-column">
       <a class="nav-link" href="#item-1">Item 1</a>
       <nav class="nav nav-pills flex-column">
         <a class="nav-link ms-3 my-1" href="#item-1-1">Item 1-1</a>
         <a class="nav-link ms-3 my-1" href="#item-1-2">Item 1-2</a>
       </nav>
       <a class="nav-link" href="#item-2">Item 2</a>
       <a class="nav-link" href="#item-3">Item 3</a>
       <nav class="nav nav-pills flex-column">
         <a class="nav-link ms-3 my-1" href="#item-3-1">Item 3-1</a>
         <a class="nav-link ms-3 my-1" href="#item-3-2">Item 3-2</a>
       </nav>
     </nav>
   </nav>

Item 1

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Item 1-1

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Item 1-2

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Item 2

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Item 3

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Item 3-1

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Item 3-2

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