.auth-card {
    max-width: 400px;
    width: 100%;
    background: linear-gradient(180deg, #fafafa 0%, #e5e5e5 100%);
    border-radius: 1rem;
    box-shadow:
        0 -8px 20px rgba(0, 0, 0, 0.12),
        0 24px 48px rgba(0, 0, 0, 0.3),
        0 8px 16px rgba(0, 0, 0, 0.2),
        inset 0 2px 10px rgba(255, 255, 255, 0.3),
        inset 0 -2px 6px rgba(0, 0, 0, 0.05);
    transition: box-shadow 0.3s ease, transform 0.2s ease;
}

.auth-btn {
    background: linear-gradient(180deg, #222 0%, #111 100%);
    color: #f8f8f8;
    letter-spacing: 0.5px;
    border-radius: 0.5rem;
    transition: all 0.2s ease;
}

.auth-btn:hover {
    background: linear-gradient(180deg, #333 0%, #111 100%);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.3);
    transform: translateY(-1px);
}

.auth-btn:active {
    background: linear-gradient(180deg, #111 0%, #000 100%);
    box-shadow: inset 0 2px 8px rgba(0, 0, 0, 0.4);
    transform: translateY(0);
}

.auth-opp-link {
    color: #222;
    position: relative;
}

.auth-opp-link:hover {
    color: #000;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

.alert {
    background-color: #e0e0e0; 
    color: #111; 
    border: 1px solid #b0b0b0; 
    box-shadow: inset 0 2px 6px rgba(0, 0, 0, 0.08);
    border-radius: 0.5rem;
}