I have this code below, and i want to add a border to make like a box using bootstrap class ".border", but i can't figure out why is not working!. Is possible using bootstrap v4?
<div class="d-flex justify-content-center">
<form>
<div class="form-group row">
<div class="col-sm-12">
<input type="email" class="form-control" id="inputEmail3" placeholder="Email">
</div>
</div>
<div class="form-group row">
<div class="col-sm-12">
<input type="password" class="form-control" id="inputPassword3" placeholder="Password">
</div>
</div>
<div class="form-group row">
<div class=" col-sm-12">
<button type="submit" class="btn btn-primary">Sign in</button>
</div>
</div>
</form>
</div>