Demo: CSS inset-block-end

<div class='container'>
    <div class='box'>Hello, World!</div>
</div>

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f0f0f0;
}

.box {
    background-color: #007BFF;
    color: white;
    padding: 20px;
    border-radius: 5px;
    position: relative;
    inset-block-end: 50px;
}
.box::after {
    content: '';
    display: block;
    height: 50px;
    background-color: transparent;
    position: absolute;
    inset-block-end: 0;
    inset-inline-start: 0;
    inset-inline-end: 0;
}

// No JavaScript required for this demo