.top-button{position:fixed;display:flex;align-items:center;justify-content:center;color:var(--bg-font-clear);background:var(--hl-light-shade);border-radius:50%;padding:12px;cursor:pointer;bottom:16px;right:16px;width:16px;height:16px;z-index:1}.top-button::before{content:'';display:block;background:var(--hl-font-dim);width:16px;height:16px;-webkit-mask-image:url("/img/arrow-up.svg?v=2");mask-image:url("/img/arrow-up.svg?v=2")}.top-button--down::before{transform:rotate(180deg)}