*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial,sans-serif;
}

body{
    min-height:100vh;
    display:flex;
    justify-content:center;
    align-items:center;
    background:#111;
    padding:20px;
}

/* FONDO OSCURECIDO */
body::before{
    content:"";
    position:fixed;
    inset:0;
    background:rgba(0,0,0,.75);
    z-index:-1;
}

/* CAJA LOGIN */

.login-box{
    width:100%;
    max-width:430px;
    background:#1f1f1f;
    padding:35px;
    border-radius:15px;
    box-shadow:0 0 30px rgba(0,0,0,.4);
}

.login-box h2{
    color:#fff;
    text-align:center;
    font-size:42px;
    margin-bottom:25px;
}

/* CAMPOS */

.login-box label{
    display:none;
}

.login-box input{
    width:100%;
    padding:14px;
    border:none;
    border-radius:8px;
    margin-bottom:12px;
    font-size:15px;
    background:#fff;
}

/* BOTÓN */

.login-box button{
    width:100%;
    padding:14px;
    margin-top:15px;
    border:none;
    border-radius:8px;
    background:#0d6efd;
    color:#fff;
    font-size:16px;
    cursor:pointer;
}

.login-box button:hover{
    opacity:.9;
}

/* LINKS */

.olvide,
.registro{
    text-align:center;
    margin-top:15px;
}

.olvide a{
    color:#ff9800;
    text-decoration:none;
}

.registro a{
    color:#4caf50;
    text-decoration:none;
}

/* ERROR */

.error{
    background:#ffdddd;
    color:#900;
    border-left:4px solid red;
    padding:12px;
    margin-bottom:15px;
    border-radius:6px;
}

/* RESPONSIVE */

@media(max-width:768px){

    .login-box{
        padding:25px;
    }

    .login-box h2{
        font-size:32px;
    }

}

@media(max-width:420px){

    .login-box{
        padding:20px;
    }

    .login-box h2{
        font-size:28px;
    }

}