веб-запрос http от пакетного файла

Попробуйте

HTML

<div class="con">
  <div class="btn1">
    <a class="btn1" href="showTable.php"><b>Reserveringen</b></a>
  </div>
  <div class="btn1">
    <a class="btn1" href="logout.php"><b>Logout</b></a>
  </div>
</div>

CSS

.con{
  min-height: 300px;
  display: flex;
  justify-content: space-between; /* here you can also use space-around or center */
  align-items: center; /* this will align then center horizontally */
}
.btn1{
  /* style the button as you like */
}