body { background: url(/_img/background_theincrediblehul.jpg) repeat top center; background-size: cover; background-attachment: fixed; min-height: 100vh; }

.logo a { width: auto; height: 86px; background: url(/_img/logo_theincrediblehulks.jpg) no-repeat 0 50%; }
.logo img { display: none; }

@media screen and (max-width: 800px) {
    .logo a { background-position: 50% 50%; }
}