html
{
 width: 100%;
 height: 100%;
}

body
{
 background-image: linear-gradient(grey, black);
}

div.textbox 
{
 color: #111;
 font-family: "Times New Roman", Times, serif;
 font-size: 40px;
 text-shadow: 0 0 2px white;
 position: fixed;
 top: 50%;
 left: 50%;
 transform: translate(-50%, -50%);
}