<head>
<style>
.container {
display:flex;
align-items:center;
width:100%;
}
.kutu1{
width:60px;
height:250px;
background-color:purple;
margin-right:30px;
}
.kutu2{
width:calc(100% - 60px);
height:250px;
background-color:purple;
}
</style>
<body>
<div class="container">
<div class="kutu1">Kutu1</div>
<div class="kutu2">Kutu2</div>
</div>
</body>
</head>
hocam 1. div sabit 2. divin enlemesine ekran boyna göre uzayacak aşağı kaymayacak