body{width:100vw;height:100vh;display:table-cell;vertical-align:middle;background:linear-gradient(to bottom,rgba(0,0,0,.3) 0%,rgba(0,0,0,.7) 75%,#000 100%),url(https://cdn.sorbonne-universite.fr/su-bg.jpg)}#login-frame{width:630px;margin:auto;background:rgba(255,255,255,.9);border:1px solid #dddada;border-radius:15px;padding:70px}@media(max-width:640px){#login-frame{width:100%;padding:20px}}