.spinner-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(255,255,255,0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    display: none;
}
.spinner-overlay.active { display: flex; }
.spinner {
    width: 40px; height: 40px;
    border: 4px solid #e5e7eb;
    border-top-color: #3b82f6;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }