Untitled

<!DOCTYPE html>
<html lang="pl">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <link rel="stylesheet">
</head>
<body>
<header>
<div class="jedynka">
    </div>

    <div class="dwa"></div>

     <div class="trzy">

     </div>

     <div class="cztery">

     </div>

     <div class="piec">

     </div>

     <div class="szesc">

     </div>

     <div class="siedem">

     </div>

     <div class="osiem">

     </div>

     <div class="dziewiec">

     </div>

     <div class="dziesiec">

     </div>

     <div class="jedenascie">

     </div>

         <div class="dwanascie">

         </div>
     </header>


</body>
</html>


*{
    margin: 0;
    padding: 0;
}
.header{
width: 1200vh;
}
div.jeden{
    display: flex;
}
div.dwa{
    display: flex;

}
div.trzy{
    display: flex;
}
div.cztery{
    display: flex;
}
div.piec{
    display: flex;
}
div.szesc{
    display: flex;
}
div.siedem{
    display: flex;
}
div.osiem{
    display: flex;
}
div.dziewiec{
    display: flex;
}
div.dziesiec{
    display: flex;
}
div.jedenascie{
    display: flex;
}
div.dwanascie{
    display: flex;
}