jellyfin-web/src/components/subtitleuploader/style.scss

.subtitleEditor-dropZone {
    border: 0.2em dashed currentcolor;
    border-radius: 0.25em;

    text-align: center;
    position: relative;
    height: 12em;
    display: flex;
    align-items: center;
    justify-content: center;
}

.raised.raised-mini.btnBrowse {
    margin-left:1.5em;
}