垂直对齐自举4

Question

我编写了以下代码：

<div class="row">
    <div class="col-md-6 col-sm-12 independence">
        <div class="container d-flex h-100">
            <div class="row justify-content-center align-self-center">
                <div class="col-md-8 offset-md-2">
                    <h2 class="mat-h2">CALCULATE THE BEST STAKE</h2>
                    <h1 class="mat-display-1"><b>KELLY STAKING</b></h1>
                    <p>
                        Calculate your own stake below.
                    </p>
                    <button mat-raised-button color="primary">Primary</button>
                </div>
            </div>
        </div>
    </div>
</div>

但是，将文本居中放置在列中似乎不起作用，我尝试了在stackoverflow上找到的方法，但这些方法也不起作用。