When adding form-group with an input, the input field will not go to 100% width of the form group which is already the width of the card.

I've tried adding styles for width directly to the parent element and to the input element itself.

```
<div class="container-fluid d-flex justify-content-center">
    <div class="card d-flex justify-content-center" style="background-color:dodgerblue; height:60vh; width:40vw; border-radius:20px">
        <div class="card-body ml-4 mt-3 text-center">

                <div class="row ml-4">
                    <div class="form-group mr-5" style="display: inline-block; width: 100%; vertical-align: middle;">
                        <label for="cardNumber">Card number</label>
                        <div class="input-group">
                            <input type="text" name="cardNumber" placeholder="Your card number" class="form-control" required>
                        </div>
                    </div>
                </div>

            <a class="btn btn-primary text-center mt-3" href="">Continue</a>
        </div>
    </div>
</div>

```

You can see what I mean in [this fiddle](https://jsfiddle.net/d1vyzbLg/) window, the input will not span 100% width of the card.