html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
    background-color: #23313a;
    color: #000;
    font-family: Roboto, sans-serif;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
    border: 0;
}

.scene {
    position: fixed;
    inset: 0;
    background-color: #23313a;
    background-image:
        linear-gradient(to bottom, rgb(35 49 58 / 0%), #000),
        url("images/ovelha.jpg");
    background-repeat: no-repeat;
    background-position: bottom;
    background-size: contain;
}

.scene:hover {
    background-image:
        linear-gradient(to bottom, rgb(35 49 58 / 30%), #000),
        url("images/ovelha.jpg");
}

.scene.is-alternate,
.scene.is-alternate:hover {
    background-color: #fff;
    background-image:
        linear-gradient(to bottom, rgb(0 0 0 / 0%), #000),
        url("images/ovelha.png");
    filter: grayscale(100%);
}