@keyframes progress-stripe {
    0%   { background-position: 40px 0; }
    100% { background-position: 0 0; }
}

.sync-running {
    background-image: linear-gradient(
        45deg,
        rgba(255,255,255,0.20) 25%, transparent 25%,
        transparent 50%, rgba(255,255,255,0.20) 50%,
        rgba(255,255,255,0.20) 75%, transparent 75%, transparent
    );
    background-size: 40px 40px;
    animation: progress-stripe 0.8s linear infinite;
    min-width: 12px;
}