.app-back{position:fixed;top:calc(env(safe-area-inset-top, 0px) + 12px);left:16px;z-index:60;display:grid;place-items:center;width:44px;height:44px;border-radius:999px;border:1px solid rgba(255,255,255,.14);background:rgba(24,24,27,.62);backdrop-filter:blur(18px) saturate(1.6);color:#fff;-webkit-tap-highlight-color:transparent;transition:transform .16s cubic-bezier(.2,.8,.2,1),background-color .16s ease}.app-back:active{transform:scale(.9);background:rgba(40,40,44,.72)}.app-back-ic{width:22px;height:22px;margin-left:-2px}.rail-hold{display:none}@media (min-width:768px){body:has(.rail-hold){--app-rail-w:76px;--app-header-h:0px;padding-left:var(--app-rail-w)}.rail-hold{display:block;position:fixed;top:0;bottom:0;left:0;z-index:50;width:76px;background:#000}}