/* Shared utility only; the existing WhatsApp control is unchanged. */
.back-to-top{position:fixed;right:max(22px,env(safe-area-inset-right,0px));bottom:calc(var(--back-to-top-offset,86px) + env(safe-area-inset-bottom,0px));z-index:199;display:grid;place-items:center;width:44px;height:44px;padding:0;border:1px solid #6aa4d88c;border-radius:13px;background:#10243aef;color:#d4f1ff;box-shadow:0 8px 24px #071b3526;cursor:pointer;opacity:0;transform:translateY(7px);pointer-events:none;transition:opacity .18s ease,transform .18s ease,background .18s ease}
.back-to-top[hidden]{display:none}
.back-to-top.is-visible{opacity:1;transform:none;pointer-events:auto}
.back-to-top:hover{background:#1b3a56;border-color:#8ad9ff}
.back-to-top:focus-visible{outline:3px solid #62caff;outline-offset:4px}
.back-to-top svg{display:block;width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
@media(max-width:900px){.back-to-top{right:max(12px,env(safe-area-inset-right,0px))}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto!important}.back-to-top{transition:none;transform:none}}