.flash-sale-banner{background-color:#ff3c3c;color:white;text-align:center;font-size:18px;font-weight:700;padding:15px 0;animation:flash 1s infinite;border-radius:5px;box-shadow:0 0 10px rgba(255,0,0,.7);margin:20px auto;width:90%;max-width:800px;z-index:9999}