body {
    background-color: #f5f5f5;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    font-family: sans-serif;
}
.form-signin {
    width: 100%;
    max-width: 330px;
    padding: 15px;
    margin: auto;
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.form-signin .form-floating:focus-within {
    z-index: 2;
}