body {
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    /* height: 100vh; Viewport height */
}
main{
    width: 95%;
}


/* // Extra small devices (portrait phones, less than 576px)
@media (max-width: 575.98px) { ... } */

/* // Small devices (landscape phones, 576px and up)*/
@media (min-width: 576px) and (max-width: 767.98px) {
    main{
        width: 85%;
    }   
}

/* // Medium devices (tablets, 768px and up)*/
@media (min-width: 768px) and (max-width: 991.98px) {
    main{
        width: 75%;
    }   
} 

/* // Large devices (desktops, 992px and up)*/
@media (min-width: 992px) and (max-width: 1199.98px) {
    main{
        width: 65%;
    }
} 

/* // Extra large devices (large desktops, 1200px and up) */
@media (min-width: 1200px) { 
    main{
        width: 40%;
    }
}