#loading-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.25);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

#loading-overlay.hidden {
    display: none;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid #ddd;
    border-top-color: #007bff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.timeline-spinner {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.6);
    z-index: 10;
}