html,body{
    height: 100%;
    width: 100%;

}
body {
    /* The image used */
    background-image: linear-gradient(
        to right,
        rgba(0, 0, 0, 0.5),
        rgba(0, 0, 0, 0.5)
    ),
    url('../img/covid.jpeg');
    /* Full height */
    height: 100%;
    /* Center and scale the image nicely */
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;

}

.nav-link {
    display: block;
    padding: 0.5rem 1rem;
    font-size: 2em;
    color: white;
}

.nav-link:hover{
    color: lightgray;
}

.welcome{
    font-size: 4rem;
    color: white;
}

.tuto{
    font-size: 3rem;
    color: white;
}

.result{
    font-size: 2rem;
    border-radius: 20px;
}

.card-header{
    font-size: 2rem;
}

.table{
    font-size: 1.3rem;
}