.c123-floating-stack{position:fixed;right:20px;z-index:99999;display:flex;flex-direction:column;gap:12px;width: 140px;}
.c123-btn{display:inline-flex;align-items:center;gap:8px;border-radius:9999px;padding:10px 14px;box-shadow:0 6px 16px rgba(0,0,0,.15);text-decoration:none;transform:translateZ(0);transition:transform .15s ease,opacity .15s ease}
.c123-btn:hover{transform:scale(1.05)}
.c123-btn.small{padding:10px;border-radius:9999px}
.c123-btn.small .txt{display:none}
.c123-btn .ico{width:20px;height:20px;display:inline-block}
.c123-btn .ico img{width:20px;height:20px;display:block}
/* Không nền: nút tròn, icon phủ kín */
.c123-btn.c123-nobg{width:52px;height:52px;padding:0;justify-content:center;background:transparent;overflow:hidden;align-self:flex-end}
.c123-btn.c123-nobg.small{width:44px;height:44px}
.c123-btn.c123-nobg.large{width:64px;height:64px}
.c123-btn.c123-nobg .txt{display:none}
.c123-btn.c123-nobg .ico,.c123-btn.c123-nobg .ico img,.c123-btn.c123-nobg .ico svg{width:100%;height:100%;display:block}
.c123-btn.c123-nobg .ico img{object-fit:cover;border-radius:50%}
@media (max-width:781.98px){.c123-hide-mobile{display:none!important}}
@media (min-width:782px){.c123-hide-desktop{display:none!important}}