JSFiddle - React, Tailwind, and code Playground

HTML

<html>
    <body>
        
        <div id="sidebar"> 
        </div>
        
        <div id="container">
            
          <div id="left_div">
             <select>
                <option>item 1</option>
                <option>item 2</option>
                <option>item 3</option>
             </select>                    
          </div>

          <div id="right_div">
              Right DIV
          </div>
                
          <table id="tbl">
              <td>Table</td>
          </table>
            
        </div> <!-- #container -->
        
        
    </body>
</html>

CSS

#sidebar {width: 8%; min-height: 200px; float: left;
          border-right: 1px solid silver;}
#container {width: 100%; padding: 0px; padding-top: 50px;}
#tbl {width: 100%; border-collapse: collapse; border: 1px solid black;}
#left_div {float: left; border: 1px solid red;}
#right_div {float: right; border: 1px solid blue;}