.redeem-modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.5); opacity: 0; visibility: hidden;
    transition: 0.3s; z-index: 1000;
}
.redeem-modal-overlay.show { opacity: 1; visibility: visible; }

.redeem-modal-panel {
    position: fixed; top: 0; right: 0; width: 400px; max-width: 90%;
    height: 100%; background: #fff; border-left: 2px solid #bfa36a;
    padding: 30px; transform: translateX(100%); transition: 0.3s;
    overflow-y: auto;
}
.redeem-modal-overlay.show .redeem-modal-panel { transform: translateX(0); }