html, body {
    /* make sure user styles defining body or html height don't break the editor */
    height: auto !important;
}
body {
    /* add some margin and padding so the content isn't crammed agains the left edge of the editor */
    margin: 0 20px !important;
    padding: 10px;

    /* You should add your own theme's colors and fonts here if your style.css or other file doens't already override the defaults set in TinyMCE */

    /*
    background-color: #fff;
    color: #000;
    font-family: Ariel, sans-serif;
    font-size: 16px;
    */
}
body img {
    /* very basic responsive images */
    max-width: 100%;
    height: auto;
}