.main {
    max-width:800px;
    margin-left:auto;
    margin-right:auto;
}

a.btn {
    text-decoration:none;
}

dialog::backdrop {
  background:
    rgba(0,0,0,0.3);
}
input, button, .btn {
    padding:10px;
    border-radius: 10px;
    margin:10px;
    text-align:center;
     box-shadow: 0px 0px 8px 0px rgba(0, 0, 0, 0.6);
}

input:focus , button:hover, a:hover, select:hover, .btn:hover {
     box-shadow: 0px 0px 8px 0px cyan;
}