I want to remove the extra space above the blue div. I am using the grid. How can I remove extra space. I can replace this layout with any other layout. I am not finding any way to remove this extra space. Please suggest any other layout or modifications in the same layout.
  
        .main {
            width: 100vw;
            max-height: A4 ;
            display: grid;
            grid-template-columns: auto auto;
        }
        .f {
            height: 100px;
            background-color: red;
            width: 100%;
            /* float: left ; */
        }
        .s {
            height: 200px;
            background-color: forestgreen;
            width: 100% ;
            /* float: right ; */
        }
        .t {
            height: 300px;
            background-color: blue;
            width: 100% ;
                        /* float: left ; */
        }
        .fo {
            height: 400px;
            background-color: gray;
            width: 100% ;
                                    /* float: right  ; */
        }
  <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
  
</head>
<body>
    <div class="main">
        <div class="f">dfdf</div>
        <div class="s">er</div>
        <div class="t">er</div>
        <div class="fo">er</div>
    </div>
</body>
</html>
 
    