html {
    height: 100%;
}
body {
    min-width: 320px; height: 100%;
    background: url('../img/5xx-bg.jpg') 50% 50% no-repeat;
    font: 14px/1.2 Arial, Helvetica, sans-serif;
    margin: 0;
    position: relative;
}
.wrapper {
    width: 100%; height: 100%;
    display: table;
    text-align: center;
}
.wrapper-inner {
    display: table-cell;
    vertical-align: middle
}
.code {
    color: #959595;
    font-size: 460px;
    line-height: 1;
}
.text {
    color: #bfbebe;
    font-size: 24px;
    line-height: 1.4;
    opacity: 0.75;
    padding: 0 20px;
}

@media (max-width: 320px) {
    .code {
        font-size: 100px;
    }
    .text {
        font-size: 18px;
    }
}
@media (min-width: 321px) and (max-width: 640px) {
    .code {
        font-size: 150px;
    }
    .text {
        font-size: 20px;
    }
}
@media (min-width: 641px) and (max-width: 768px) {
    .code {
        font-size: 220px;
    }
    .text {
        font-size: 22px;
    }
}
@media (min-width: 769px) and (max-width: 1024px) {
    .code {
        font-size: 300px;
    }
}
@media (min-width: 1025px) and (max-width: 1200px) {
    .code {
        font-size: 400px;
    }
}