.locked-challenge {
    position: relative;
    pointer-events: none;
    filter: grayscale(0.8);
}

.locked-challenge::after {
    content: 'Locked';
    position: absolute;
    inset: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background: rgba(0, 0, 0, 0.6);
    color: #fff;
    font-weight: bold;
    font-size: 1.25rem;
}

.timed-challenge.pending {
    opacity: 0.6;
}

.timed-challenge.unlocked {
    animation: anticheat-pulse 1s ease-in-out infinite;
}

@keyframes anticheat-pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}