:root{--bg:#05070d;--fg:#e8f2ff;--accent:#38e8ff;--accent-dim:#38e8ff59}*{box-sizing:border-box}html,body{background:var(--bg);height:100%;color:var(--fg);-webkit-user-select:none;user-select:none;-webkit-tap-highlight-color:transparent;overscroll-behavior:none;margin:0;padding:0;font-family:system-ui,-apple-system,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;overflow:hidden}#camera,#scene,#overlay{width:100vw;height:100vh;display:block;position:fixed;inset:0}#camera{object-fit:cover;z-index:0;background:#000}#camera.fit-contain{object-fit:contain}#scene{z-index:1;pointer-events:none}#overlay{z-index:2;pointer-events:none}#hud{top:calc(env(safe-area-inset-top,0px) + 8px);z-index:3;color:#9fe8ff;text-shadow:0 1px 3px #000;opacity:.75;pointer-events:none;gap:10px;font:12px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace;display:flex;position:fixed;left:12px}#hud[hidden]{display:none}#btn-recenter{top:calc(env(safe-area-inset-top,0px) + 10px);right:calc(env(safe-area-inset-right,0px) + 12px);z-index:3;width:46px;height:46px;color:var(--fg);-webkit-backdrop-filter:blur(10px);background:#0c14208c;border:1px solid #ffffff29;border-radius:50%;padding:0;font-size:21px;line-height:1;position:fixed}#btn-recenter[hidden]{display:none}#btn-recenter.alert{color:#1a1204;background:linear-gradient(#ffd479,#eda63a);border-color:#ffd479e6;animation:1.6s ease-out infinite recenter-pulse}@keyframes recenter-pulse{0%{box-shadow:0 0 #ffc4548c}70%{box-shadow:0 0 0 14px #ffc45400}to{box-shadow:0 0 #ffc45400}}#start-screen{z-index:4;background:radial-gradient(120% 90% at 50% 0,#123 0%,#05070d 60%);place-items:center;padding:24px;display:grid;position:fixed;inset:0}#start-screen[hidden]{display:none}.card{text-align:center;flex-direction:column;gap:12px;width:min(420px,100%);display:flex}.card h1{letter-spacing:.14em;color:#fff;text-shadow:0 0 24px var(--accent-dim);margin:0;font-size:40px}.card .sub{color:#9fb3c8;margin:0 0 8px;font-size:14px;line-height:1.6}button{appearance:none;cursor:pointer;border:0;border-radius:12px;padding:14px 18px;font-family:inherit;font-size:16px;transition:transform .12s,background .2s,opacity .2s}button:active{transform:scale(.98)}button:disabled{opacity:.45;cursor:default}button.primary{color:#04121a;background:linear-gradient(#46f0ff,#12a7cc);font-weight:700}button.ghost{color:#cfe3f5;background:#ffffff0f;border:1px solid #ffffff24}.status{color:#ffd479;min-height:20px;margin:4px 0 0;font-size:13px;line-height:1.5}.status.error{color:#ff8080}.help{text-align:left;color:#8ea3b8;border:1px solid #ffffff1a;border-radius:10px;margin-top:6px;padding:8px 12px;font-size:13px}.help summary{cursor:pointer;color:#a8c4dd}.help ol{margin:8px 0 2px;padding-left:20px;line-height:1.7}