<body style="-webkit-writing-mode: vertical-lr">
<div style="inline-size: 600px; margin-block-end:50px">
    <span style="padding-inline-start: 15px; padding-inline-end:15px; padding-block-start:5px; padding-block-end: 5px; font-size: 48px; background-color:blue">
    <span style="
        padding-inline-start: 15px; padding-inline-end:15px;
        font-size: 48px;
        background-color: lightyellow;
        -webkit-border-radius: 10px;
        border: 5px solid green;
        line-height: 1.5;
    ">
        This sentence is too long to fit on a single line.
    </span></span>
</div>