body {
    min-height: 100vh;
    background-image: url("../img/upv-background.jpg");
    background-color: rgba(56, 56, 56);
    background-repeat: no-repeat;
    background-blend-mode: multiply;
    background-position: center;
    background-size: cover;
}

header {
    /* mismo borde que las cards */
    border: 1px solid var(--bs-card-border-color, var(--bs-border-color-translucent));
}