.vjs-playlist-now-playing-text {
    font-size: 0; /* Hide original text */
}

.vjs-playlist-now-playing-text::after {
    content: "In riproduzione";
    font-size: 16px;
}

.vjs-playlist .vjs-up-next-text {
    font-size: 0; /* Hide original text */
}

.vjs-up-next-text::after {
    content: "Prossimo video";
    font-size: 16px;
}