Edit in JSFiddle

<h1 class="shadow1">見出し１</h1>

.shadow1 {
    color: #fff;
    font-size: 100px;
    text-shadow:
        3px 3px 0 #000,
        3px -3px 0 #000,
        -3px 3px 0 #000,
        -3px -3px 0 #000;
}