.leaflet-measure-path-measurement {
    position: absolute;
    font-size: 12px;
    color: black;
    text-shadow: -2px 0 0 white, -2px -2px 0 white, 0 -2px 0 white, 2px -2px 0 white, 2px 0 0 white, 2px 2px 0 white, 0 2px 0 white, -2px 2px 0 white;
    white-space: nowrap;
    transform-origin: 0;
}

    .leaflet-measure-path-measurement > div {
        position: relative;
        margin-top: -25%;
        left: -50%;
        font-size: 12px;
    }