:root{--back-button-z-index: 1000;--overlay-z-index: 100}html,body{width:100vw;height:100vh;padding:0;margin:0;overflow:hidden}#root{position:relative;width:100%;height:100%}.button{position:fixed;top:16px;left:16px;z-index:var(--back-button-z-index);display:flex;align-items:center;justify-content:center;width:40px;height:40px;font-size:28px;color:#000;text-decoration:none;background:#fff9}