<head>
<style>
.inlineTest {
	font-size:24px;
	 background-color:grey;
         -webkit-mask-box-image: url(resources/mask.png) 75 / auto / 10px;
    padding:75px 10px;
    line-height:3
}
</style>
</head>
<body style="-webkit-writing-mode: vertical-rl">
<span class="inlineTest">This content should be masked<br> with a soft glow.</span>