body{
    display:flex;
    flex-direction:column;
    align-items:center;
    background: #000000;
}

#container{
     width:400px;
     margin:0 auto;
     margin-top:10%;
     margin-right:50%;
     margin-left:50%;
}

form {
     width:100%;
     padding: 30px;
     border: 1px solid #f1f1f1;
     background: #fff;
     box-shadow: 0 0 20px 0 rgba(0, 0, 0, 0.2), 0 5px 5px 0 rgba(0, 0, 0, 0.24);
}

#container h1{
     width: 38%;
     margin: 0 auto;
     padding-bottom: 10px;
}

input[type=text], input[type=password] {
     width: 100%;
     padding: 12px 20px;
     margin: 8px 0;
     display: inline-block;
     border: 1px solid #ccc;
     box-sizing: border-box;
}

.submit {
    display:block;
    width:400px;
    background-image:linear-gradient( #363839, black);
    text-align:center;
    box-sizing:border-box;
    padding:20px;
    margin:1px;
    color: #ffffff;
    text-decoration:none;
    transition: all 0.3s ease;
}

.submit:hover {
    color: red;
    transition: all 1s ease;
}