body{margin:0;padding:0;font-family:sans-serif;background: #34495e;}
.box{
    width: 300px;
    padding:40px;
    position: absolute;
    top:50%;
    left:50%;
    transform: translate(-50%,-50%);
    background: #191919;
    text-align: center;
    border-radius: 20px;
    opacity: 0.9;
}
.box h1{
    color:white;
    text-transform: uppercase;
    font-weight: 500;
}
.box input[type="text"],.box input[type="password"]{
    border: 0;
    background: none;
    display: block;
    margin: 20px auto;
    text-align: center;
    border: 2px solid #3498db;
    padding: 14px 10px;
    width: 200px;
    outline: none;
    color: white;
    border-radius: 24px;
    transition: 0.25s;
}
.box input[type="text"]:focus,.box input[type="password"]:focus{
    width: 280px;
    border-color: #2ecc71;
}
.box input[type="submit"]{
    border: 0;
    background: none;
    display: block;
    margin: 20px auto;
    text-align: center;
    border: 2px solid #2ecc71;
    padding: 14px 40px;
    outline: none;
    color: white;
    border-radius: 24px;
    transition: 0.25s;
    cursor: pointer;
}
.box input[type="submit"]:hover{
    background: #2ecc71;
}