/* Persistent navigation across study modes. */
:root{--nav-width:144px}
body>.sidebar,body.experiment-screen>.sidebar,body.practice-screen>.sidebar,body.experiment-screen.workbench-focused>.sidebar{display:flex!important;width:var(--nav-width);padding:18px 10px;align-items:stretch;z-index:40}
body>.sidebar .brand{font-size:16px;gap:7px;letter-spacing:0}body>.sidebar .brandmark{width:32px;height:34px;font-size:21px;flex:none}body>.sidebar .brand>span:last-child{display:block!important}body>.sidebar .brand small{display:none}body>.sidebar .side-label,body>.sidebar .route,body>.sidebar .side-bottom{display:none}body>.sidebar nav{width:100%;margin-top:32px}body>.sidebar .nav{font-size:13px!important;display:flex;justify-content:flex-start;padding:13px 8px;gap:8px;min-height:48px}body>.sidebar .nav span{font-size:22px}body>.sidebar .nav b{display:none}
body .workspace,body.experiment-screen .workspace,body.practice-screen .workspace,body.experiment-screen.workbench-focused .workspace{margin-left:var(--nav-width)!important}
.global-nav{position:fixed;inset:0 auto 0 0;width:var(--nav-width);background:#edf1e9;border-right:1px solid #d7e1d6;z-index:40;padding:20px 10px;display:flex;flex-direction:column;color:#203d38}
.global-brand{display:flex;align-items:center;gap:8px;color:#175f53;text-decoration:none;font-weight:750;font-size:25px}.global-brand span{font-size:16px}.global-nav nav{margin-top:32px}.global-nav nav a{display:flex;gap:9px;align-items:center;padding:13px 8px;margin:5px 0;border-radius:9px;color:inherit;text-decoration:none;font-size:13px;min-height:48px}.global-nav nav b{font-size:22px;font-weight:400}.global-nav nav a.active{background:#166b60;color:white}.global-nav nav a:hover{background:#d7e5d8;color:#175f53}.global-nav small{margin-top:auto;color:#718375;line-height:1.9;padding:10px}
body.lecture-study>header,body.lecture-study>main{margin-left:var(--nav-width)}body.lecture-study>#directory{left:var(--nav-width)}
@media(max-width:760px){:root{--nav-width:66px}body>.sidebar{padding:12px 4px!important}body>.sidebar .brand{justify-content:center}body>.sidebar .brand>span:last-child{display:none!important}body>.sidebar .nav{font-size:10px!important;flex-direction:column;gap:0;padding:8px 0;line-height:1.5;white-space:nowrap}body>.sidebar nav{margin-top:18px}.global-nav{padding:12px 4px}.global-brand{justify-content:center}.global-brand span,.global-nav small{display:none}.global-nav nav{margin-top:18px}.global-nav nav a{flex-direction:column;gap:0;font-size:10px;padding:8px 0;white-space:nowrap}.global-nav nav b{font-size:22px}body.lecture-study>header{gap:7px;padding:8px}body.lecture-study>header b{font-size:14px}body.lecture-study>header>a{font-size:11px}body.lecture-study>header button{padding:5px;font-size:10px}}
@media print{.global-nav{display:none!important}body.lecture-study>header,body.lecture-study>main{margin-left:0}}
/* A single, explicit geometry for every main navigation surface. */
body>.site-rail,body.experiment-screen>.site-rail,body.practice-screen>.site-rail,body.experiment-screen.workbench-focused>.site-rail{box-sizing:border-box!important;position:fixed!important;inset:0 auto 0 0!important;display:flex!important;flex-direction:column!important;align-items:stretch!important;width:var(--nav-width)!important;height:100dvh!important;max-height:none!important;padding:18px 10px!important;border:0!important;border-right:1px solid #d7e1d6!important;background:#edf1e9!important;box-shadow:none!important;overflow:hidden!important;color:#203d38!important;font:500 13px/1.6 'Microsoft YaHei','PingFang SC',system-ui,sans-serif!important;z-index:40!important}
body>.site-rail .rail-brand{box-sizing:border-box!important;display:flex!important;align-items:center!important;justify-content:flex-start!important;gap:7px!important;flex:none!important;height:36px!important;min-height:36px!important;margin:0!important;padding:0!important;font:700 16px/1.3 'Microsoft YaHei','PingFang SC',system-ui,sans-serif!important;letter-spacing:0!important;color:#203d38!important;text-decoration:none!important;white-space:nowrap!important}
body>.site-rail .rail-mark{display:grid!important;place-items:center!important;flex:0 0 32px!important;width:32px!important;height:34px!important;border-radius:9px!important;background:#166b60!important;color:white!important;font-size:21px!important;line-height:1!important;box-shadow:3px 3px 0 #d4ded2!important}
body>.site-rail .rail-name{display:inline!important;font-size:16px!important;line-height:1.3!important}
body>.site-rail>nav{display:flex!important;flex-direction:column!important;flex:none!important;gap:5px!important;width:100%!important;margin:32px 0 0!important;padding:0!important;border:0!important}
body>.site-rail>nav>.rail-item{box-sizing:border-box!important;display:flex!important;flex-direction:row!important;align-items:center!important;justify-content:flex-start!important;flex:none!important;gap:8px!important;width:100%!important;height:52px!important;min-height:52px!important;max-height:52px!important;margin:0!important;padding:0 8px!important;border:0!important;border-radius:9px!important;background:transparent!important;box-shadow:none!important;color:#203d38!important;font:600 13px/1.6 'Microsoft YaHei','PingFang SC',system-ui,sans-serif!important;text-align:left!important;text-decoration:none!important;white-space:nowrap!important;cursor:pointer!important}
body>.site-rail .rail-icon{display:flex!important;align-items:center!important;justify-content:center!important;flex:0 0 24px!important;width:24px!important;height:28px!important;font:400 22px/1 system-ui,sans-serif!important}
body>.site-rail .rail-label{display:inline!important;font:600 13px/1.6 'Microsoft YaHei','PingFang SC',system-ui,sans-serif!important}
body>.site-rail>nav>.rail-item.active{background:#166b60!important;color:#fff!important}body>.site-rail>nav>.rail-item:not(.active):hover{background:#e0e9dc!important}
body>.site-rail>.rail-footer{display:block!important;flex:none!important;margin:auto 0 0!important;padding:10px!important;font:400 11px/1.9 'Microsoft YaHei','PingFang SC',system-ui,sans-serif!important;color:#718375!important}
@media(max-width:760px){body>.site-rail,body.experiment-screen>.site-rail,body.practice-screen>.site-rail,body.experiment-screen.workbench-focused>.site-rail{padding:12px 4px!important}body>.site-rail .rail-brand{justify-content:center!important}body>.site-rail .rail-name{display:none!important}body>.site-rail>nav{margin-top:18px!important}body>.site-rail>nav>.rail-item{flex-direction:column!important;justify-content:center!important;gap:2px!important;height:58px!important;min-height:58px!important;max-height:58px!important;padding:4px 0!important}body>.site-rail .rail-icon{flex:0 0 26px!important;height:26px!important}body>.site-rail .rail-label{font-size:10px!important;line-height:1.4!important}body>.site-rail>.rail-footer{display:none!important}}
@media print{body>.site-rail{display:none!important}}