JSFiddle - React, Tailwind, and code Playground

HTML

<div class="submenu">
         <div class="menu"><span>item1<span></div>
         <div class="menu"><span>item2<span></div>
         <div class="menu"><span>item3<span></div>
         <div class="menu"><span>item4<span></div>
         <div class="menu"><span>item5<span></div>
         <div class="menu"><span>item6<span></div>
         <div class="menu"><span>item7<span></div>
         <div class="menu"><span>item8<span></div>
         <div class="menu"><span>item9<span></div> 
         <div class="menu"><span>item10<span></div>
             
     </div>

CSS

.submenu {
  -webkit-column-count: 4;
  -webkit-column-gap:   20px;  
  -moz-column-count:    2;
  -moz-column-gap:      20px;
  column-count:         2;
  column-gap:           20px;
}
.submenu{height:100px;border:solid 1px red;}