JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://bootswatch.com/bower_components/bootstrap/dist/css/bootstrap.min.css">
<link rel="stylesheet" href="https://bootswatch.com/cosmo/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
    <div class="col-sm-12 col-lg-12" style="margin-left:0px;padding-right:0px;margin-top:50px;padding-left:0px; height:100vh;">

  <div style="background-color:white;width:100%;height:100%;">

    <div style="margin-left:30px;margin-right:50px;padding-top:30px;">
    
    <form >
    <div class=form-inline style='text-align:center;'>
    <select name="Form1" class="form-control" >
                <option value="0">Form1</option>
                <option value="1">Option2</option>
                <option value="2">Option3</option>
    </select>
    
    <select name="Form2" class="form-control" >
                <option value="0">Form2</option>
                <option value="1">Option2</option>
                <option value="2">Option3</option>
    </select>
    
    <select name="Form3" class="form-control" >
                <option value="0">Form3</option>
                <option value="1">Option2</option>
                <option value="2">Option3</option>
    </select>

    <button type="submit" class="btn btn-default">Submit</button>

    </div>
    
    
    </form>
    
    
    </div>
    
  </div>

</div>

CSS

.form-inline {
    display: flex;
    justify-content: center;
  }
  
  .form-control {

        border-radius:0px;  
}

 .btn{

        border-radius:0px;  
}