JSFiddle - React, Tailwind, and code Playground

HTML

<body>
                 <div id="header">
        <h1>Barra superior</h1>
   </div>
   <div id="leftcolumn">
        <h1>Conteúdo</h1>
   </div>
          <div id="content">
                         <h1>conteudo</h1>
                        </div>
   <div id="footer">
        <address>fim</address>
   </div>
  
  </body>

CSS

*{
margin: 0px;
padding: 0px;
}
#body{
text-align:center;
}
#header{
background:#C09;
height:100px;
line-height:100px;
position:static;
width:100%;
top:0;
}
#leftcolumn {
background: #2675a8;
float: left;
width: 25%;
height: 700px;
}
#content {
background:#3F3;
float: left;
width: 75%;
height: 700px;
}
#footer {
background: #df781c;
clear: both;
width: 100%;
}