LayoutTests/fast/css/appearance-apple-pay-button.html

<style>
    .container {
        position: relative;
        background-color: silver;
        padding: 25px;
        width: 500px;
    }
    .apple-pay-button-div {
        display :block;
        margin: 25px;
        -webkit-appearance: -apple-pay-button;
        height: 100px;
        width: 400px;
    }
    
    .masker {
        position: absolute;
        width: 200px;
        height: 80px;
        background-color: blue;
    }

    .corner-mask {
        position: absolute;
        width: 20px;
        height: 20px;
        background-color: blue;
    }
</style>

<div class="container">
    <button style="-apple-pay-button-style: black;" class="apple-pay-button-div"></button>
    <button style="-apple-pay-button-style: white;" class="apple-pay-button-div"></button>
    
    <div class="masker" style="top: 60px; left: 150px"></div>
    <div class="masker" style="top: 185px; left: 150px"></div>

    <div class="corner-mask" style="top: 45px; left: 45px"></div>
    <div class="corner-mask" style="top: 135px; left: 45px"></div>
    <div class="corner-mask" style="top: 45px; left: 435px"></div>
    <div class="corner-mask" style="top: 135px; left: 435px"></div>

    <div class="corner-mask" style="top: 170px; left: 45px"></div>
    <div class="corner-mask" style="top: 260px; left: 45px"></div>
    <div class="corner-mask" style="top: 170px; left: 435px"></div>
    <div class="corner-mask" style="top: 260px; left: 435px"></div>
</div>