:root{color:#111d2b;font-synthesis:none;background:#fff;font-family:Inter,PingFang SC,Microsoft YaHei,system-ui,sans-serif}*{box-sizing:border-box}body{margin:0}button,input,textarea{font:inherit}button,a{touch-action:manipulation}a{color:inherit;text-decoration:none}button{color:inherit}.boot{text-align:center;color:#536173;place-content:center;gap:16px;min-height:100vh;display:grid}.topbar{z-index:20;background:#fff;border-bottom:1px solid #e4eaed;align-items:center;height:64px;padding:0 28px;display:flex;position:sticky;top:0}.brand{white-space:nowrap;align-items:center;gap:10px;font-weight:760;display:flex}.brand-mark{color:#fff;background:#176c70;border-radius:7px;place-items:center;width:30px;height:30px;font-family:Georgia,serif;display:grid}.topbar nav{gap:28px;margin:auto;font-size:14px;display:flex}.topbar nav a{color:#536173;border-bottom:2px solid #0000;align-items:center;height:64px;display:flex}.topbar nav a.active{color:#176c70;border-color:#176c70}.account{align-items:center;gap:16px;font-size:13px;display:flex}.text-button{color:#536173;cursor:pointer;background:0 0;border:0;padding:7px}.global-error{color:#963d2d;background:#fff4f1;padding:9px 28px;font-size:13px}.page{max-width:1120px;margin:0 auto;padding:76px 44px 100px}.home{max-width:1040px}.eyebrow{letter-spacing:.14em;color:#176c70;text-transform:uppercase;margin:0 0 14px;font-size:12px;font-weight:750;line-height:1.4}.page h1,.lesson h1{letter-spacing:-.035em;margin:0;font-size:38px;line-height:1.25}.lead{color:#536173;max-width:760px;margin:20px 0 30px;font-size:19px;line-height:1.75}.primary{color:#fff;cursor:pointer;background:#176c70;border:1px solid #176c70;border-radius:7px;padding:11px 18px;font-weight:680}.primary:disabled{opacity:.55;cursor:wait}.link-button{align-items:center;gap:8px;display:inline-flex}.wide{width:100%}.route-section{margin-top:76px}.route-section h2,.record-section h2{font-size:22px}.route-list{border-top:1px solid #dfe6e8;margin:24px 0;padding:0;list-style:none}.route-list li{border-bottom:1px solid #dfe6e8;grid-template-columns:50px 1fr;align-items:start;padding:19px 4px;display:grid}.route-list li>span{color:#7c8994;padding-top:3px;font:600 13px ui-monospace,monospace}.route-list a{gap:5px;display:grid}.route-list strong{font-size:17px}.route-list small,.three-doors small{color:#677481;font-size:14px}.three-doors{border-top:1px solid #dfe6e8;border-bottom:1px solid #dfe6e8;grid-template-columns:repeat(3,1fr);margin-top:62px;display:grid}.three-doors>a{border-right:1px solid #dfe6e8;gap:15px;padding:27px 22px;display:flex}.three-doors>a:last-child{border:0}.three-doors svg{color:#176c70;width:20px}.three-doors span{gap:7px;display:grid}.catalog>.lead{margin-bottom:56px}.unit{border-top:1px solid #dfe6e8;grid-template-columns:280px 1fr;padding:26px 0 38px;display:grid}.unit-heading{gap:16px;padding-right:30px;display:flex}.unit-heading>span{color:#176c70;font:650 13px ui-monospace}.unit-heading h2{margin:0;font-size:18px;line-height:1.5}.topic{border-bottom:1px solid #edf1f2;grid-template-columns:60px 1fr auto;align-items:center;gap:14px;padding:12px 3px;display:grid}.topic span{color:#77848e;font:13px ui-monospace}.topic strong{font-size:15px}.topic em{color:#176c70;font-size:12px;font-style:normal}.topic.pending{color:#7b8790}.topic.pending em{color:#8b959c;background:#f3f5f6;border-radius:3px;padding:3px 7px}.lesson-list{border-top:1px solid #dfe6e8}.lesson-list>a{border-bottom:1px solid #dfe6e8;grid-template-columns:65px 1fr auto;align-items:start;gap:22px;padding:25px 4px;display:grid}.lesson-list>a>span{color:#176c70;font-size:12px}.lesson-list h2{margin:0 0 7px;font-size:19px}.lesson-list p{color:#65727d;margin:0;line-height:1.6}.lesson-list small{color:#77848e;align-items:center;gap:5px;display:flex}.record-section{margin:50px 0}.record{border-top:1px solid #e4eaed;justify-content:space-between;padding:16px 2px;display:flex}.record small{color:#72808b}.empty{color:#7a8791}.reader{grid-template-columns:220px minmax(500px,1fr) 72px;height:calc(100vh - 64px);display:grid;overflow:hidden}.reader.panel-open{grid-template-columns:220px minmax(440px,1fr) 72px 360px}.reader.panel-open:has(.source-wide){grid-template-columns:180px minmax(440px,1fr) 60px minmax(480px,44vw)}.outline{background:#f7f9fa;border-right:1px solid #e4eaed;padding:25px 0;overflow:auto}.outline .back{color:#66737e;align-items:center;gap:5px;padding:0 20px 24px;font-size:13px;display:flex}.outline>p{color:#176c70;letter-spacing:.09em;margin:0;padding:0 20px 8px;font-size:11px}.outline>h2{margin:0;padding:0 20px 20px;font-size:15px;line-height:1.5}.outline nav button{text-align:left;cursor:pointer;background:0 0;border:0;border-left:3px solid #0000;grid-template-columns:29px 1fr;gap:4px;width:100%;padding:10px 17px;font-size:13px;line-height:1.45;display:grid}.outline nav button span{color:#89939a;font:11px ui-monospace}.outline nav button.active{color:#176c70;background:#eef5f4;border-left-color:#176c70}.lesson{scrollbar-gutter:stable;padding:54px clamp(40px,6vw,90px) 80px;overflow:auto}.lesson>*{max-width:780px;margin-left:auto;margin-right:auto}.lesson h1{font-size:32px}.lesson-subtitle{color:#687580;margin-top:12px;font-size:17px}.lesson-rule{background:#dfe6e8;height:1px;margin-top:30px;margin-bottom:50px}.lesson section h2{letter-spacing:-.02em;margin:5px 0 25px;font-size:26px;line-height:1.4}.lesson section>p:not(.section-count){margin:0 0 20px;font-family:Songti SC,SimSun,serif;font-size:17px;line-height:1.9}.section-count{color:#176c70;margin:0;font:12px ui-monospace}.lesson ul{padding-left:22px}.lesson li{margin:8px 0;font-size:16px;line-height:1.75}.example,.feynman{background:#eef8f7;border-left:3px solid #176c70;margin:30px 0;padding:22px 25px}.example>span,.feynman>span,.sources>span{letter-spacing:.12em;color:#176c70;font-size:11px;font-weight:800}.example h3{margin:9px 0;font-size:16px}.example p,.feynman p{margin:8px 0!important;font-family:inherit!important;font-size:15px!important;line-height:1.75!important}.feynman{background:#f7f9fa;border-color:#9aa8af}.feynman small{color:#67747e;line-height:1.5}.sources{border-top:1px solid #e4eaed;flex-wrap:wrap;align-items:center;gap:10px;margin:30px 0 10px;padding-top:16px;display:flex}.sources button{color:#176c70;cursor:pointer;background:#fff;border:1px solid #ccd7da;border-radius:6px;padding:7px 10px;font-size:13px}.next-row{border-top:1px solid #e4eaed;justify-content:space-between;margin-top:60px;padding-top:22px;display:flex}.next-row button{cursor:pointer;color:#65727d;background:0 0;border:0;align-items:center;gap:6px;display:flex}.next-row .next{color:#176c70}.next-row button:disabled{opacity:.4}.panel-launcher{border-left:1px solid #e4eaed;flex-direction:column;gap:6px;padding-top:30px;display:flex}.panel-launcher button{color:#596874;cursor:pointer;background:0 0;border:0;flex-direction:column;align-items:center;gap:5px;padding:10px 4px;font-size:11px;display:flex}.panel-launcher svg{width:18px}.support-panel{background:#fff;border-left:1px solid #dfe6e8;flex-direction:column;display:flex;overflow:hidden}.support-panel>header{border-bottom:1px solid #e4eaed;justify-content:space-between;align-items:center;height:54px;padding:0 12px;display:flex}.support-panel>header nav{gap:4px;display:flex}.support-panel>header button{cursor:pointer;background:0 0;border:0;padding:9px 8px}.support-panel>header nav button{color:#75818b;font-size:13px}.support-panel>header nav button.active{color:#176c70;border-bottom:2px solid #176c70}.support-panel>header svg{width:18px}.panel-body{padding:28px 24px;overflow:auto}.panel-body h2{margin:0 0 18px;font-size:21px}.panel-body label,.auth-box label{gap:8px;margin:18px 0;font-size:13px;font-weight:650;display:grid}.panel-body textarea,.auth-box input{resize:vertical;border:1px solid #bdc9cd;border-radius:6px;outline:none;padding:11px 12px;line-height:1.6}.panel-body textarea:focus,.auth-box input:focus{border-color:#176c70;box-shadow:0 0 0 3px #e3f0ef}.related{border-top:1px solid #e4eaed;grid-template-columns:48px 1fr 16px;align-items:center;gap:7px;padding:14px 0;font-size:14px;display:grid}.related span{color:#176c70;font:11px ui-monospace}.related svg{width:15px}.muted,.privacy-note,.field-help,.invite-note{color:#66747f;line-height:1.65}.privacy-note,.field-help,.invite-note{font-size:12px}.form-error{color:#a13c2d;background:#fff2ef;border-radius:5px;padding:9px 11px;font-size:13px}.success{color:#176c70;font-size:13px}.status{color:#56646f;font-size:13px}.mori-answer{background:#eef8f7;border-radius:6px;margin-top:20px;padding:17px}.mori-answer span{color:#176c70;font-size:11px;font-weight:800}.mori-answer p{white-space:pre-wrap;line-height:1.7}.source-panel{flex-direction:column;flex:1;min-height:0;display:flex}.document-picker{border-bottom:1px solid #e4eaed;gap:5px;padding:9px;display:flex;overflow:auto}.document-picker button{white-space:nowrap;background:#f2f5f5;border:0;border-radius:5px;padding:7px 9px;font-size:12px}.document-picker button.active{color:#fff;background:#176c70}.source-panel iframe{border:0;flex:1;width:100%}.empty-panel{text-align:center;color:#77838c;margin:auto;padding:40px}.empty-panel svg{width:30px}.auth-page{background:#f7f9fa;place-items:center;min-height:100vh;padding:50px;display:grid}.auth-box{background:#fff;border:1px solid #dfe6e8;width:420px;padding:42px 44px}.auth-box h1{margin:0 0 12px;font-size:30px}.auth-box input{width:100%}.auth-box form{margin-top:28px}.invite-note{text-align:center;margin:22px 0 0}@media (width<=1300px){.topbar nav{gap:15px}.reader{grid-template-columns:180px minmax(480px,1fr) 64px}.reader.panel-open{grid-template-columns:180px minmax(440px,1fr) 64px 340px}.outline>h2,.outline>p,.outline .back{padding-left:15px;padding-right:15px}.lesson{padding-left:45px;padding-right:45px}}