html, body {
    height: 100%;
    margin: 0;
}
body {
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}
.auth-container {
    width: 100%;
    max-width: 420px;
    padding: 2rem;
}
.auth-card {
    background: #fff;
    border-radius: 16px;
    padding: 2.5rem 2rem;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}
.auth-logo {
    text-align: center;
    margin-bottom: 1.5rem;
}
.auth-logo h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: #1a1a2e;
    margin: 0;
}
.auth-logo p {
    color: #6c757d;
    margin: 0.3rem 0 0;
    font-size: 0.9rem;
}
.form-floating {
    margin-bottom: 1rem;
}
.form-floating .form-control {
    border-radius: 10px;
    border: 1.5px solid #dee2e6;
    padding: 1rem 0.75rem;
}
.form-floating .form-control:focus {
    border-color: #0f3460;
    box-shadow: 0 0 0 0.2rem rgba(15,52,96,0.15);
}
.btn-auth {
    width: 100%;
    padding: 0.75rem;
    border-radius: 10px;
    font-weight: 600;
    font-size: 1rem;
    background: linear-gradient(135deg, #0f3460, #1a1a2e);
    border: none;
    color: #fff;
    cursor: pointer;
    transition: transform 0.1s, box-shadow 0.2s;
}
.btn-auth:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 15px rgba(15,52,96,0.4);
    color: #fff;
}
.btn-auth:disabled {
    opacity: 0.6;
    transform: none;
}
.auth-switch {
    text-align: center;
    margin-top: 1.2rem;
    font-size: 0.9rem;
    color: #6c757d;
}
.auth-switch a {
    color: #0f3460;
    font-weight: 600;
    text-decoration: none;
}
.auth-switch a:hover {
    text-decoration: underline;
}
.alert {
    border-radius: 10px;
    font-size: 0.85rem;
}
.auth-card .form-floating label {
    color: #6c757d;
}