html {
    background-image: url('http://cdn.superbwallpapers.com/wallpapers/beaches/blue-horizon-29002-1920x1200.jpg');
    background-position: center center;
    background-size: cover;
    background-repeat: no-repeat;
}

html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
}

.centerbox {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    max-width: 400px;
}

.centerbox input {
    border: none;
    background-color: transparent;
    width: 100px;
    resize: horizontal;
}

.centerbox input:focus {
    outline: none;
}

.centerbox .buttons {
    text-align: center;
    padding-top: 16px;
}

.centerbox .buttons .button {
    padding: 8px;
    border: solid 1px;
    border-radius: 4px;
    background-color: dodgerblue;
    border-color: navy;
    color: white;
}

.centerbox .buttons .button[disabled] {
    border-color: silver;
    background-color: #F4F4F4;
    color: silver;
}

/* Common styles to text, input and button */
.centerbox,
.centerbox input,
.centerbox .buttons .button {
    font-size: 21px;
    font-family: sans-serif;
}