.zalo-btn{position:fixed;bottom:20px;right:20px;width:60px;height:60px;border-radius:50%;background-color:#007aff;display:flex;align-items:center;justify-content:center;box-shadow:0 4px 6px rgba(0,0,0,.1);cursor:pointer;overflow:hidden}.zalo-btn img{width:35px;height:35px;z-index:1}.zalo-btn .ripple{position:absolute;width:100%;height:100%;background:hsla(0,0%,100%,.3);border-radius:50%;animation:ripple 1.5s ease-out infinite}@keyframes ripple{0%{transform:scale(.8);opacity:.8}50%{transform:scale(1.5);opacity:.4}to{transform:scale(2.5);opacity:0}}