openwebrx-clone/htdocs/css/openwebrx-globals.css

html, body
{
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: "DejaVu Sans", Verdana, Geneva, sans-serif;
}

.sprite {
    background-image: url(../gfx/openwebrx-sprites.png);
    display: inline-block;
}

.openwebrx-button.highlighted .sprite {
    background-image: linear-gradient(rgba(255,127,0,0.5), rgba(255,127,0,0.5)), url(../gfx/openwebrx-sprites.png);
    background-blend-mode: overlay;
}

@media only screen and (-webkit-min-device-pixel-ratio: 2),
only screen and (min-device-pixel-ratio: 2) {
    .sprite {
        background-image: url(../gfx/openwebrx-sprites-2x.png);
        background-size: 198px 77px;
    }
}