jellyfin-web/src/components/subtitlesync/subtitlesync.css

.subtitleSyncContainer {
    width: 40%;
    margin-left: 30%;
    margin-right: 30%;
    height: 4.2em;
    background: rgba(28, 28, 28, 0.8);
    border-radius: .3em;
    color: #fff;
    position: absolute;
}

.subtitleSync-closeButton {
    position: absolute;
    top: 0;
    right: 0;
    color: #ccc;
    z-index: 2;
}

.subtitleSyncTextField {
    position: absolute;
    left: 0;
    width: 40%;
    margin-left: 30%;
    margin-right: 30%;
    top: 0.1em;
    text-align: center;
    font-size: 20px;
    color: white;
    z-index: 2;
}

#prompt {
    flex-shrink: 0;
}

.subtitleSyncSliderContainer {
    width: 98%;
    margin-left: 1%;
    margin-right: 1%;
    top: 2.5em;
    height: 1.4em;
    -webkit-box-flex: 1;
    -webkit-flex-grow: 1;
    flex-grow: 1;
    border-radius: .3em;
    z-index: 1;
}