body {
    font-family: 'Segoe UI', Arial, sans-serif;
    margin: 0;
    min-height: 100vh;
    display: grid;
    place-items: center;
    background: linear-gradient(135deg, #0ea5e9, #6366f1);
    color: #fff;
}
.offline-container {
    text-align: center;
    padding: 3rem;
    background: rgba(15, 23, 42, 0.6);
    border-radius: 24px;
    box-shadow: 0 25px 50px rgba(15, 23, 42, 0.35);
}
.spinner {
    margin: 2rem auto;
    width: 64px;
    height: 64px;
    border-radius: 50%;
    border: 6px solid rgba(255, 255, 255, 0.2);
    border-top-color: #fff;
    animation: spin 1s linear infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}
footer {
    margin-top: 2rem;
    font-size: 0.85rem;
    opacity: 0.85;
}