index.css

/* css styles */

/*body {
    background-image: -moz-linear-gradient(top, rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url("images/banner.jpg");
    background-image: -webkit-linear-gradient(top, rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url("images/banner.jpg");
    background-image: -ms-linear-gradient(top, rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url("images/banner.jpg");
    background-image: linear-gradient(top, rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url("images/banner.jpg");
    background-attachment: fixed;
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
}

/*#hero-home {
    padding: 8em 0 14em 0;
    text-align: center;
    margin-top: 20px;
    margin-bottom: 20px;
    margin-left: 24px;
    margin-right: 24px;
}

    #hero-home h1 {
        font-size: 2.25em;
        margin: 0 0 1em 0;
        padding: 14px 0px 14px 0px;
        border-top: 1.2px solid #dee2e6;
        border-bottom: 1.2px solid #dee2e6;
    }

    #hero-home p {
        font-size: 1.24em;
        line-height: 1.4em;
        text-align: center;
    }

    #hero-welcome {
        background-color: #212121;
        opacity: 0.6;
        padding: 40px 0 20px 0;
        margin-top: 0px;
        margin-bottom: 10px;
        margin-left: 30px;
        margin-right: 30px;
        border-top: 1px solid #dee2e6;
        border-bottom: 1px solid #dee2e6;
    }

        #hero-welcome p {
            font-size: 1.24em;
            line-height: 1.4em;
            text-align: center;
        }

    #hero-welcome-box {
        background-color: #212121;
    }

*/
.content-block {
    padding-top: 20px;
    padding-bottom: 10px;
    padding-left: 10px;
    padding-right: 10px;
    margin-top: 20px;
    margin-bottom: 40px;
    margin-left: 24px;
    margin-right: 24px;
    /*background-color: rgba(0, 0, 0, 0.5);
    border-top: 1px solid #dee2e6;
    border-bottom: 1px solid #dee2e6;
    /*border-left: 1px solid #dee2e6;
    border-right: 1px solid #dee2e6;*/
}
      
@media(min-width: 900px) {
.content-block {
    margin-left: 50px;
    margin-right: 50px;
}
}
      
@media (min-width: 1200px) {
.content-block {
    max-width: 1100px;
    margin-left: auto;
    margin-right: auto;
}
}