.back-to-top{position:fixed;right:20px;bottom:calc(20px + env(safe-area-inset-bottom,0px));z-index:40;display:inline-flex;align-items:center;justify-content:center;width:48px;height:48px;padding:0;border:1px solid #ffffff75;border-radius:50%;background:#163e4e;color:#fff;box-shadow:0 4px 18px #10293930;cursor:pointer;transition:background-color .15s,transform .15s}
.back-to-top[hidden]{display:none}
.back-to-top svg{width:23px;height:23px;pointer-events:none}
.back-to-top:hover{background:#17657c;opacity:1;transform:translateY(-2px)}
.back-to-top:focus-visible{outline:3px solid #348fa9;outline-offset:4px}
@media(max-width:650px){.back-to-top{right:16px;bottom:calc(16px + env(safe-area-inset-bottom,0px))}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto!important}.back-to-top{transition:none}}