@media (max-width: 640px) {
    .container-root {
        max-width: 96%;
        margin: 0 auto;
    }

    .intro_class {
        display: flex;
        justify-content: center;
    }

    .nav_block {
        display: none;
    }
}

@media (min-width: 641px) and (max-width:767px) {
    .container-root {
        max-width: 96%;
        margin: 0 auto;
    }

    .intro_class {
        display: flex;
        justify-content: center;
    }
}


/* Medium   Device */
@media (min-width: 768px) and (max-width:991px) {
    .container-root {
        max-width: 96%;
        margin: 0 auto;
    }

    #skills {
        display: none;
    }
}

/* Large Device */
@media (min-width: 901px) and (max-width:1000px) {
    .container-root {
        max-width: 96%;
        margin: 0 auto;
    }
}

@media (min-width: 1001px) and (max-width:1100px) {
    .container-root {
        max-width: 95%;
        margin: 0 auto;
    }
}

@media (min-width: 1101px) and (max-width:1200px) {
    .container-root {
        max-width: 90%;
        margin: 0 auto;
    }
}

@media (min-width: 1201px) and (max-width:1300px) {}

@media (min-width: 1301px) and (max-width:1400px) {}

@media (min-width: 1401px) and (max-width:1500px) {}

@media (min-width: 1501px) and (max-width:1900px) {}