@media only screen and (max-width: 767px) {
    html,
    body {
        background-color: #f6f6f6;
    }
    #navbar {
        position: static;
        background-color: #fff;
        top: 0;
        width: 100%;
        max-height: 275px;
        z-index: 1;
        border: none;
        padding: 0;
        margin: 0;
        overflow-y: auto;
        overflow-x: hidden;
    }
    #navbar ul {
        position: absolute;
        margin: 0;
        padding: 0;
        width: 100%;
        border: 1px solid;
        height: 207px;
        font-weight: 400;
        border-bottom: 2px solid;
    }
    #navbar ul li {
        padding-left: 45px;
        border-left: 0;
        color: #4d4e53;
    }
    #main-doc {
        margin-left: 0;
        position: relative;
        margin-top: 30px;
    }
}

@media only screen and (min-width: 1024px) {
    #demo {
        width: 60%;
    }
}