html, body, div, object, iframe, fieldset {
margin: 0;
padding: 0;
border: 0;

<iframe src="http://shilohgameblog.wordpress.com"></iframe>

body {
        margin: 0;
        padding: 0;
    }

    iframe {
        display: block;
        width: 100vw;
        height: 100vh;
        max-width: 100%;
        margin: 0;
        padding: 0;
        border: 0 none;
        box-sizing: border-box;
    }