/* Shared UndoAI version switcher: external stylesheet for reader CSP. */
nav.undoai-vswitch{position:fixed;inset:auto 20px 20px auto;z-index:2147483000;display:flex;align-items:center;justify-content:flex-start;gap:8px;margin:0;padding:6px;border-radius:999px;background:#f7f9fc;border:1px solid #c4cbd6;box-shadow:0 8px 28px rgba(22,35,59,.18);font:500 14px/1.2 -apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;color:#16233b;width:max-content;max-width:calc(100vw - 32px);box-sizing:border-box;letter-spacing:0;text-align:left}
nav.undoai-vswitch *{box-sizing:border-box}
nav.undoai-vswitch .undoai-vswitch-group{display:flex;align-items:center;gap:2px;margin:0;padding:0}
nav.undoai-vswitch a{text-decoration:none!important;box-shadow:none;line-height:1.2;letter-spacing:0;white-space:nowrap}
nav.undoai-vswitch .undoai-vswitch-item{display:inline-flex;align-items:center;justify-content:center;min-height:44px;margin:0;padding:0 16px;border:0;border-radius:999px;color:#56657d;background:transparent;font-weight:500;font-size:14px}
nav.undoai-vswitch .undoai-vswitch-item:hover{background:#e8f1ff;color:#0868cf}
nav.undoai-vswitch .undoai-vswitch-item.is-active{background:#0868cf;color:white}
nav.undoai-vswitch .undoai-vswitch-source{display:inline-flex;align-items:center;justify-content:center;min-height:44px;margin:0;padding:0 15px;border:1px solid #bdc8d7;border-radius:999px;color:#29476a;background:#fff;font-size:14px;font-weight:500}
nav.undoai-vswitch .undoai-vswitch-source:hover{border-color:#0868cf;background:#edf5ff;color:#0868cf}
nav.undoai-vswitch a:focus-visible{outline:3px solid #78aff0;outline-offset:2px}
body.has-toc .content{padding-bottom:160px}body.has-toc .back-top{bottom:100px}
@media(max-width:640px){nav.undoai-vswitch{right:12px;bottom:calc(12px + env(safe-area-inset-bottom,0px));left:auto;max-width:calc(100vw - 24px);padding:6px;gap:6px;display:grid;border-radius:24px}nav.undoai-vswitch .undoai-vswitch-group{justify-content:center}nav.undoai-vswitch .undoai-vswitch-item{min-height:44px;padding:0 15px;font-size:14px}nav.undoai-vswitch .undoai-vswitch-source{display:flex;min-height:44px;width:100%;font-size:14px}body.has-toc .back-top{bottom:150px}body.has-toc .content{padding-bottom:180px}}
@media print{nav.undoai-vswitch{display:none}}