.content-wrapper{
        max-width: 1000px;
        margin-left: auto;
        margin-right: auto;
    }
    body {
        background-color: cadetblue;
        class= .content-wrapper;
    }
    body h4{
        color: black;
        font-size: medium; 
        border: 2px solid black;
        background-color: darkgray;
    }
    body h3{
        color: black;
        font-size: large; 
        border: 4px solid black;
        background-color: darkgray;
    }
        <!--background: 
            repeating-linear-gradient(
            45deg,
            darkgrey,
            darkgrey 10px,
            gray 10px,
            gray 20px );-->
    body img{
        border: 2px dashed black;
    }
    body a{
        color: black;
    }