Prevent zero in nested ordered list when using css counters

Question

I am styling an HTML nested ordered list (numbered). I am trying to achieve same layout as MS Word has usually when you press Tab before the numbered list item. Ex:

1. Item at top
1.1.1.1. Item at middle
2. Item at bottom

For now I have the following CSS which sets 1.0.0.1 for the Item at middle. Is there any way to fix that with CSS and without changing the HTML?

ol { counter-reset: itemCounter; padding-left: 0 }
ol li { list-style: none; }
ol li:not(:has(ol)):before {
    content: counters(itemCounter, ".") ". ";
    counter-increment: itemCounter;
}

<ol>
   <li>Item at top</li>
   <li>
      <ol>
         <li>
            <ol>
               <li>
                  <ol>
                     <li>Item at middle</li>
                  </ol>
               </li>
            </ol>
         </li>
      </ol>
   </li>
   <li>Item at bottom</li>
</ol>

Answer 1

This seems to work as you need it to:

ol { counter-reset: itemCounter; padding-left: 0 }
ol li { list-style: none; }
ol li:not(:has(ol)):before {
    content: counters(itemCounter, ".") ". ";
    counter-increment: itemCounter;
}

ol>li:has(ol) {
  counter-increment: itemCounter 0;
}

ol>li ol li:has(ol) {
  counter-increment: itemCounter 1;
}

<ol>
   <li>Item at top</li>
   <li>
      <ol>
         <li>
            <ol>
               <li>
                  <ol>
                     <li>Item at middle</li>
                     <li>Item at middle</li>
                  </ol>
               </li>
            </ol>
         </li>
         <!-- a few li for testing  -->
         <li>
            <ol>
               <li>
                  <ol>
                     <li>Item at middle</li>
                  </ol>
               </li>
               <li>
                  <ol>
                     <li>Item at middle</li>
                     <li>Item at middle</li>
                  </ol>
               </li>
            </ol>
         </li>
      </ol>
   </li>
   <li>Item at bottom</li>
</ol>