JSFiddle - React, Tailwind, and code Playground

HTML

<div class="menu"><include src="menu.html"></include></div><!--
    --><div class="grid">
           <div class="cell" id="cell1"></div><!--
        --><div class="cell" id="cell2"><include src="2.html"></include></div><!--
        --><div class="cell" id="cell3"><include src="3.html"></include></div><!--
        --><div class="cell" id="cell4"><include src="4.html"></include></div>
       </div>

CSS

* {margin:0;padding:0}
     html,body {
           background:gray;
           overflow:hidden;
           width:100%;
           height:100%;
     }
     .cell.iframe.include{line-height:0;}
     div {
	        box-sizing: border-box;
	   -moz-box-sizing: border-box;
	-webkit-box-sizing: border-box;
           line-height:1.2em;
     }

    .cell iframe {
      border:0 none;
      display:inline-block;
      width:100%;
      height:100%;
    }

   /* configure zones */
    .menu {
          display:inline-block;
          background:#555555;
          height:100vh;
          vertical-align:top;
          width:20vw;
          min-width:20vw;
     }
    .grid {
           display:inline-block;
           vertical-align:top;
           line-height:0;
           width:80%;
           height:100vh;
    }

   /* configurate cells */
    .cell {
       display:inline-block;
       border:1px red solid;
       width:50%;
       height:50vh;
       overflow:auto;
    }

    .cell:nth-child(3n+1) {
       background:teal;
    }

 /*configure elements in cells*/
    .cell .info {
          background-color:red;
          position:relative;
          right:0.8em;
          float:right;
          bottom:0;
          margin-top:-1.9em;
          display:inline-block;
          z-index:0;
          font-size:24px;
    }
    .cell h1 {
       padding:10px;
    }

JavaScript

function loadWithScrollCorrect(f,id) {
       var o=document.getElementById(id);
        includeHTML(f,o,function() {
          if(o.getElementsByTagName("iframe").length>0)
               o.style.overflow="hidden";
       });
   };
   //loadWithScrollCorrect('1.html','cell1');
   /*    
   Если загружаем здесь блок(и), тогда убираем теги <include></include> из соответствующих ячеек.
   */