.hero-biblioteca {
    background-image:
        linear-gradient(
            rgba(20, 42, 45, 0.72),
            rgba(20, 42, 45, 0.72)
        ),
        url("../img/descarga.jpg");

    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;

    min-height: 420px;
    display: flex;
    align-items: center;
}