.fhc-wrap{position:fixed;right:var(--fhc-right);bottom:var(--fhc-bottom);z-index:99999;display:flex;flex-direction:column;gap:var(--fhc-gap);align-items:center}
.fhc-btn{width:var(--fhc-size);height:var(--fhc-size);border:0;border-radius:50%;display:flex;align-items:center;justify-content:center;color:#fff;text-decoration:none;cursor:pointer;box-sizing:border-box;box-shadow:0 6px 20px rgba(0,0,0,.2);transition:transform .2s ease,box-shadow .2s ease,opacity .2s ease;font:700 13px/1 Arial,sans-serif}
.fhc-btn:hover{transform:translateY(-2px) scale(1.04);box-shadow:0 8px 24px rgba(0,0,0,.28);color:#fff}
.fhc-btn:focus-visible{outline:3px solid rgba(0,0,0,.22);outline-offset:3px}
.fhc-btn svg{width:52%;height:52%;fill:currentColor}
.fhc-phone{background:var(--fhc-phone)}
.fhc-zalo{background:var(--fhc-zalo)}
.fhc-top{background:var(--fhc-top);opacity:0;visibility:hidden;transform:translateY(10px);pointer-events:none}
.fhc-top.fhc-show{opacity:1;visibility:visible;transform:translateY(0);pointer-events:auto}
.fhc-top.fhc-show:hover{transform:translateY(-2px) scale(1.04)}
.fhc-zalo-text{font-weight:800;font-size:calc(var(--fhc-size) * .24);letter-spacing:-.2px;color:#fff}
@media(max-width:768px){.fhc-wrap{right:max(12px,var(--fhc-right));bottom:max(16px,var(--fhc-bottom))}.fhc-btn{box-shadow:0 4px 15px rgba(0,0,0,.22)}}
@media(prefers-reduced-motion:reduce){.fhc-btn{transition:none}}