:root{--ink:#202729;--ink-soft:#465154;--muted:#7b8587;--paper:#fbfbf9;--paper-warm:#f6f5f1;--sidebar:#f0f2ef;--line:#e0e3df;--line-strong:#cdd3cf;--accent:#2c6269;--accent-soft:#e4efef;--highlight:#e8d89b;--warm:#9c6848;--danger:#9a4e3b;--shadow:0 18px 55px #1c272821}*{box-sizing:border-box}html,body{min-height:100%;margin:0}body{color:var(--ink);background:var(--paper);text-rendering:optimizelegibility;font-family:Inter,SF Pro Text,Noto Sans SC,PingFang SC,Microsoft YaHei,system-ui,sans-serif}button,input,textarea{font:inherit}button{color:inherit}button:focus-visible,input:focus-visible,textarea:focus-visible{outline-offset:2px;outline:2px solid #79a8ae}::selection{color:#15272a;background:#c9e3e3}.login-page{background:radial-gradient(circle at 15% 18%, #639c9f21, transparent 32%), radial-gradient(circle at 84% 76%, #a7785217, transparent 30%), var(--paper-warm);place-items:center;min-height:100vh;padding:28px;display:grid;position:relative;overflow:hidden}.login-background{color:#2c626926;letter-spacing:.2em;align-items:center;width:min(760px,80vw);font-family:Songti SC,Noto Serif SC,serif;font-size:13px;display:flex;position:absolute;top:12%;left:50%;transform:translate(-50%)}.login-background i{background:currentColor;flex:1;height:1px;margin:0 18px}.login-card{z-index:1;-webkit-backdrop-filter:blur(18px);backdrop-filter:blur(18px);background:#fffffdf0;border:1px solid #cdd3cfeb;border-radius:16px;gap:9px;width:min(400px,100%);padding:38px 39px 30px;display:grid;position:relative;box-shadow:0 26px 80px #1f2b2a24}.login-card header{align-items:center;gap:14px;margin-bottom:21px;display:flex}.login-mark{width:48px;height:48px;color:var(--accent);background:#fff;border:1px solid #aebfbd;border-radius:50%;place-items:center;font-family:Songti SC,Noto Serif SC,serif;font-size:21px;font-weight:700;display:grid}.login-card h1{margin:0;font-family:Songti SC,Noto Serif SC,serif;font-size:25px}.login-card header p{color:var(--muted);margin:4px 0 0;font-size:10px}.login-card label{color:#657174;margin-top:7px;font-size:10px;font-weight:700}.login-card input{border:1px solid var(--line-strong);width:100%;height:43px;color:var(--ink);background:#fff;border-radius:8px;outline:none;padding:0 12px}.login-card input:focus{border-color:#7fa4a8;box-shadow:0 0 0 3px #2c626917}.login-card>button{color:#fff;background:var(--accent);cursor:pointer;border:0;border-radius:8px;height:43px;margin-top:14px;font-size:12px;font-weight:700}.login-card>button:hover{background:#22545b}.login-card>button:disabled{cursor:wait;opacity:.58}.login-error{color:var(--danger);margin:5px 0 -4px;font-size:10px}.login-card footer{color:#9aa2a2;text-align:center;margin-top:14px;font-size:8px}.app-shell{background:var(--paper);grid-template-columns:64px minmax(0,1fr);height:100vh;transition:grid-template-columns .24s;display:grid;overflow:hidden}.app-shell.nav-open{grid-template-columns:300px minmax(0,1fr)}.sidebar{z-index:45;border-right:1px solid var(--line);background:var(--sidebar);min-width:0;display:flex;position:relative;overflow:hidden}.sidebar-rail{background:#f5f6f3;border-right:1px solid #cdd3cfb8;flex-direction:column;align-items:center;gap:12px;width:64px;min-width:64px;height:100vh;padding:17px 0;display:flex}.nav-toggle{cursor:pointer;background:0 0;border:0;border-radius:8px;place-content:center;gap:4px;width:36px;height:36px;display:grid}.nav-toggle:hover,.rail-action:hover{background:#e6e9e5}.nav-toggle span{background:#546164;width:16px;height:1px;display:block}.brand-mini{width:36px;height:36px;color:var(--accent);background:var(--paper);border:1px solid #aeb8b5;border-radius:50%;place-items:center;margin:5px 0 8px;font-family:Songti SC,Noto Serif SC,serif;font-size:17px;font-weight:700;display:grid}.rail-action{color:#596669;cursor:pointer;background:0 0;border:0;border-radius:8px;place-items:center;width:36px;height:36px;font-size:18px;display:grid}.rail-status{background:#62ad89;border-radius:50%;width:7px;height:7px;margin-top:auto;box-shadow:0 0 0 4px #62ad891f}.sidebar-expanded{opacity:0;flex-direction:column;gap:28px;width:236px;min-width:236px;height:100vh;padding:25px 18px 18px;transition:opacity .18s,transform .22s;display:flex;transform:translate(-8px)}.nav-open .sidebar-expanded{opacity:1;transform:none}.sidebar-brand strong{letter-spacing:.12em;font-family:Songti SC,Noto Serif SC,serif;font-size:23px;display:block}.sidebar-brand span{color:var(--muted);margin-top:4px;font-size:10px;display:block}.new-topic{gap:9px;display:grid}.new-topic label,.sidebar-label{color:#667174;letter-spacing:.08em;font-size:10px;font-weight:700}.new-topic textarea{resize:none;border:1px solid var(--line-strong);width:100%;color:var(--ink);background:#ffffffad;border-radius:9px;outline:none;padding:11px 12px;font-size:12px;line-height:1.6}.new-topic textarea::placeholder{color:#a0a7a6}.new-topic textarea:focus{background:#fff;border-color:#7fa4a8;box-shadow:0 0 0 3px #2c626914}.primary-button{color:#f8fbfa;background:var(--accent);cursor:pointer;border:0;border-radius:8px;padding:10px 12px;font-size:11px;font-weight:700}.primary-button:hover{background:#22545b}.primary-button:disabled{cursor:not-allowed;opacity:.45}.topic-list{align-content:start;gap:5px;min-height:0;display:grid;overflow-y:auto}.topic-list>.sidebar-label{margin-bottom:3px}.topic-list>button{text-align:left;cursor:pointer;background:0 0;border:1px solid #0000;border-radius:8px;gap:4px;width:100%;padding:10px 11px;display:grid}.topic-list>button:hover{background:#ffffff9e}.topic-list>button.active{background:#fff;border-color:#d5dad6;box-shadow:0 2px 9px #313f3c0a}.topic-list>button span{text-overflow:ellipsis;white-space:nowrap;font-size:12px;font-weight:600;overflow:hidden}.topic-list>button small{color:#929b9c;font-size:9px}.muted{color:var(--muted);font-size:11px;line-height:1.6}.sidebar-footer{color:#91999a;align-items:center;gap:7px;margin-top:auto;font-size:8px;display:flex}.sidebar-footer span{background:#62ad89;border-radius:50%;width:5px;height:5px}.reader{background:var(--paper);flex-direction:column;min-width:0;min-height:0;display:flex}.reader-toolbar{z-index:10;border-bottom:1px solid var(--line);-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);background:#fbfbf9ed;justify-content:space-between;align-items:center;min-height:66px;padding:0 28px;display:flex;position:relative}.reader-title span{color:#949c9d;margin-bottom:2px;font-size:9px;display:block}.reader-title strong{font-size:13px;font-weight:650}.reader-actions{gap:7px;display:flex}.reader-actions button{color:#5f6b6e;cursor:pointer;background:0 0;border:1px solid #0000;border-radius:8px;padding:8px 11px;font-size:10px;position:relative}.reader-actions button:hover{border-color:var(--line);background:#f5f6f3}.reader-actions b{color:var(--accent);margin-left:4px}.reader-actions i{background:var(--warm);border-radius:50%;width:5px;height:5px;animation:.8s infinite alternate soft-pulse;position:absolute;top:4px;right:4px}.reading-scroll{flex:1;min-height:0;padding:62px clamp(28px,7vw,110px) 100px;overflow-y:auto}.lesson{max-width:800px;margin:0 auto}.page-kicker{color:var(--accent);letter-spacing:.08em;font-size:10px;font-weight:750}.lesson-header{margin-bottom:43px}.lesson h1,.empty-state h1{letter-spacing:-.03em;font-family:Songti SC,Noto Serif SC,Georgia,serif;font-weight:650}.lesson h1{max-width:740px;margin:12px 0 17px;font-size:clamp(39px,5vw,56px);line-height:1.18}.lead{color:#465255;max-width:720px;margin:0;font-family:Songti SC,Noto Serif SC,Georgia,serif;font-size:19px;line-height:1.78}.lesson-meta{color:#8a9394;flex-wrap:wrap;gap:10px 22px;margin-top:24px;font-size:9px;display:flex}.lesson-meta span{align-items:center;gap:7px;display:flex}.lesson-meta span:before{content:"";background:#9ca8a8;border-radius:50%;width:3px;height:3px}.selectable-content{-webkit-user-select:text;user-select:text}.prose{border-top:1px solid var(--line);padding-top:10px}.prose p{color:#303a3d;margin:0;padding:22px 0;font-family:Songti SC,Noto Serif SC,Georgia,serif;font-size:17px;line-height:2}.prose p+p{border-top:1px solid #eceeeb}.annotated-term{color:inherit;cursor:pointer;font-family:inherit;font-size:inherit;line-height:inherit;background:linear-gradient(#0000 76%,#7bb1b429 0);border:0;border-bottom:1px dashed #78a0a4;margin:0;padding:0 1px 1px;display:inline}.annotated-term:hover{color:#1d565e;background:#b8dbdb59}.annotated-term.pinned{border-bottom-style:solid;border-bottom-color:var(--warm);background:linear-gradient(#0000 74%,#d0b17e3b 0)}.suggestion-groups{border-top:1px solid var(--line-strong);gap:22px;margin-top:42px;padding-top:25px;display:grid}.suggestion-groups h4{color:#7d8789;margin:0 0 10px;font-size:10px;font-weight:650}.suggestion-list{flex-wrap:wrap;gap:8px;display:flex}.suggestion-chip{cursor:pointer;background:#fafaf7;border:1px solid #d9dfdb;border-radius:999px;align-items:center;gap:7px;padding:8px 10px;display:flex}.suggestion-chip:hover{background:#f1f7f6;border-color:#91afb1}.suggestion-chip:disabled{cursor:wait;opacity:.5}.suggestion-chip span{font-size:11px;font-weight:700}.suggestion-chip small{color:#919a9b;font-size:8px}.lesson-footer{border-top:1px solid var(--line);color:#919a9a;justify-content:space-between;margin-top:50px;padding-top:17px;font-size:9px;display:flex}.lesson-footer button{color:var(--accent);cursor:pointer;background:0 0;border:0;font-size:9px}.error-banner{z-index:5;color:#7e4130;background:#fff4ef;border:1px solid #ddb8a7;border-radius:8px;max-width:800px;margin:0 auto 24px;padding:10px 12px;font-size:11px;position:sticky;top:0}.empty-state{max-width:720px;margin:6vh auto 0}.empty-symbol{width:180px;color:var(--accent);justify-content:space-between;align-items:center;margin-bottom:35px;font-family:Songti SC,serif;font-size:21px;display:flex;position:relative}.empty-symbol span,.empty-symbol b{background:#fff;border:1px solid #aebfbd;border-radius:50%;place-items:center;width:46px;height:46px;font-weight:500;display:grid}.empty-symbol i{background:#b7c4c2;flex:1;height:1px}.empty-symbol i:after{content:"";background:var(--warm);border-radius:50%;width:5px;height:5px;margin:-2px auto 0;display:block}.empty-state h1{margin:13px 0 20px;font-size:clamp(40px,5vw,57px);line-height:1.24}.empty-state>p{color:#697476;max-width:620px;font-family:Songti SC,serif;font-size:16px;line-height:1.9}.empty-state>button{border:1px solid var(--line-strong);color:var(--accent);cursor:pointer;background:#fff;border-radius:8px;margin-top:15px;padding:10px 14px;font-size:11px}.definition-popover{z-index:110;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);background:#fffffdfa;border:1px solid #cdd6d2;border-radius:13px;width:min(360px,100vw - 24px);animation:.14s ease-out popover-in;position:fixed;overflow:hidden;box-shadow:0 20px 60px #1f2e2d33}.definition-popover.above{transform-origin:bottom;transform:translateY(-100%)}.definition-popover>header{justify-content:space-between;align-items:flex-start;padding:16px 17px 11px;display:flex}.definition-popover>header span{color:#8d9696;margin-bottom:3px;font-size:8px;display:block}.definition-popover>header strong{font-family:Songti SC,serif;font-size:21px}.definition-popover>header button{color:#7d8787;cursor:pointer;background:0 0;border:0;border-radius:50%;width:27px;height:27px;font-size:18px}.definition-popover>header button:hover{background:#f0f2ef}.definition-content{padding:2px 17px 14px}.definition-primary{color:#2c3638;margin:0;font-family:Songti SC,serif;font-size:14px;line-height:1.75}.contextual-meaning{background:#f0f5f4;border-left:2px solid #7aa2a5;border-radius:0 7px 7px 0;margin-top:13px;padding:11px 12px}.contextual-meaning span{color:var(--accent);margin-bottom:4px;font-size:8px;font-weight:700;display:block}.contextual-meaning p{color:#536063;margin:0;font-size:11px;line-height:1.6}.definition-example{color:#727c7d;margin:11px 0 0;font-size:10px;line-height:1.6}.definition-example span{width:17px;height:17px;color:var(--warm);background:#f4ece5;border-radius:50%;place-items:center;margin-right:6px;font-size:8px;display:inline-grid}.definition-popover>footer{background:#fafaf7;border-top:1px solid #e7eae6;justify-content:space-between;align-items:center;gap:10px;min-height:47px;padding:8px 12px 8px 17px;display:flex}.definition-popover>footer>span{color:#909999;white-space:nowrap;font-size:8px}.definition-popover>footer>span.failed{color:var(--danger)}.definition-popover>footer>div{gap:5px;display:flex}.definition-popover>footer button{cursor:pointer;border:0;border-radius:7px;padding:7px 9px;font-size:9px;font-weight:650}.pin-action{color:#677274;background:#ecefeb}.pin-action.active{color:#7a543a;background:#f1e8df}.deepen-action{color:#fff;background:var(--accent)}.definition-loading{align-items:center;gap:13px;min-height:135px;padding:15px 18px 25px;display:flex}.definition-loading>span{background:#72aeb2;border-radius:50%;width:9px;height:9px;animation:.75s infinite alternate soft-pulse}.definition-loading div{gap:8px;width:100%;display:grid}.definition-loading i{background:#edf0ed;border-radius:5px;height:8px;animation:1s infinite alternate shimmer;display:block}.definition-loading i:nth-child(2){width:88%}.definition-loading i:nth-child(3){width:62%}.definition-error{padding:8px 17px 22px}.definition-error strong{color:var(--danger);font-size:12px}.definition-error p{color:#8b7771;margin:6px 0 0;font-size:10px}@keyframes popover-in{0%{opacity:0;scale:.98}}@keyframes soft-pulse{to{opacity:.42;transform:scale(.78)}}@keyframes shimmer{to{background:#e2e9e6}}.knowledge-drawer{z-index:70;pointer-events:none;background:#f7f8f5;border-left:1px solid #d6dcd8;width:min(440px,100vw - 70px);height:100vh;transition:transform .25s;position:fixed;top:0;right:0;transform:translate(105%);box-shadow:-18px 0 55px #1d2b2a1c}.knowledge-drawer.open{pointer-events:auto;transform:none}.drawer-header{border-bottom:1px solid var(--line);background:#fafaf7f5;justify-content:space-between;align-items:center;height:66px;padding:0 19px 0 22px;display:flex}.drawer-header span{color:#979f9f;margin-bottom:2px;font-size:8px;display:block}.drawer-header strong{font-size:13px}.drawer-header>button{color:#657173;cursor:pointer;background:0 0;border:0;border-radius:50%;width:31px;height:31px;font-size:20px}.drawer-header>button:hover{background:#e9ece8}.drawer-scroll{height:calc(100vh - 66px);padding:18px 18px 45px;overflow-y:auto}.drawer-backdrop{display:none}.drawer-trail{gap:3px;margin:0 2px 13px;display:flex;overflow-x:auto}.drawer-trail button{color:#818b8c;cursor:pointer;white-space:nowrap;background:0 0;border:0;gap:5px;padding:0;font-size:9px;display:flex}.drawer-trail button:last-child{color:var(--accent);font-weight:700}.drawer-progress{color:#5f7778;background:var(--accent-soft);border-radius:7px;margin-bottom:9px;padding:8px 10px;font-size:9px}.concept-card{background:#fff;border:1px solid #d7dcd8;border-radius:12px;padding:25px 24px 28px;box-shadow:0 12px 35px #29363412}.card-kicker{color:var(--accent);font-size:8px;font-weight:700}.concept-card h2{margin:10px 0 13px;font-family:Songti SC,serif;font-size:28px;line-height:1.35}.card-summary{color:#3d4a4c;background:#eef3f1;border-radius:8px;margin:0;padding:13px 14px;font-family:Songti SC,serif;font-size:13px;line-height:1.75}.card-body{margin-top:19px}.card-body p{color:#465153;border-top:1px solid #eaede9;margin:0;padding:15px 0;font-family:Songti SC,serif;font-size:13px;line-height:1.85}.drawer-loading{text-align:center;place-content:center;justify-items:center;min-height:65vh;display:grid}.drawer-loading>span{border:2px solid #d2dcd9;border-top-color:var(--accent);border-radius:50%;width:18px;height:18px;margin-bottom:16px;animation:.8s linear infinite spin}.drawer-loading strong{font-family:Songti SC,serif;font-size:17px}.drawer-loading p{color:#899293;max-width:240px;font-size:10px;line-height:1.6}@keyframes spin{to{transform:rotate(360deg)}}.annotation-summary{border-bottom:1px solid var(--line);grid-template-columns:auto 1fr;align-items:baseline;gap:0 7px;margin:4px 2px 18px;padding-bottom:15px;display:grid}.annotation-summary strong{color:var(--accent);font-family:Songti SC,serif;font-size:31px}.annotation-summary span{font-size:11px;font-weight:650}.annotation-summary small{color:#929b9b;grid-column:2;font-size:8px}.pending-list{gap:5px;margin-bottom:13px;display:grid}.pending-list span{color:#5e7071;background:var(--accent-soft);border-radius:7px;align-items:center;gap:7px;padding:8px 10px;font-size:9px;display:flex}.pending-list i{background:#69a8ad;border-radius:50%;width:6px;height:6px;animation:.7s infinite alternate soft-pulse}.annotation-list{gap:9px;display:grid}.annotation-card{background:#fff;border:1px solid #dce1dd;border-radius:10px;padding:14px 14px 12px}.annotation-card.pinned{background:#fffdf9;border-color:#d4c2ad}.annotation-card header{justify-content:space-between;align-items:center;display:flex}.annotation-card header strong{font-family:Songti SC,serif;font-size:16px}.annotation-card header button{color:#7e8989;cursor:pointer;background:#f0f2ef;border:0;border-radius:6px;padding:4px 7px;font-size:8px}.annotation-card.pinned header button{color:#7d583f;background:#f1e8df}.annotation-card>p{color:#435052;margin:9px 0 6px;font-family:Songti SC,serif;font-size:12px;line-height:1.65}.annotation-card>small{color:#7f898a;font-size:9px;line-height:1.55;display:block}.annotation-card footer{border-top:1px solid #ecefeb;justify-content:space-between;align-items:center;margin-top:10px;padding-top:9px;display:flex}.annotation-card footer span{color:#a0a7a7;font-size:8px}.annotation-card footer button{color:var(--accent);cursor:pointer;background:0 0;border:0;font-size:9px;font-weight:650}.annotation-empty{text-align:center;place-content:center;justify-items:center;min-height:55vh;display:grid}.annotation-empty span{color:#8fa8a7;font-size:35px}.annotation-empty p{color:#8c9595;max-width:210px;font-size:10px;line-height:1.65}.busy-indicator,.deep-indicator{z-index:95;color:#445254;box-shadow:var(--shadow);background:#fffffdf5;border:1px solid #c9d3cf;border-radius:9px;align-items:center;gap:8px;padding:9px 12px;font-size:9px;display:flex;position:fixed;bottom:19px;right:20px}.busy-indicator span,.deep-indicator span{background:#65a8ac;border-radius:50%;width:7px;height:7px;animation:.75s infinite alternate soft-pulse}.deep-indicator{right:460px}.eyebrow{color:var(--accent);letter-spacing:.08em;font-size:8px;font-weight:750}.secondary-button{border:1px solid var(--line-strong);cursor:pointer;background:#fff;border-radius:8px;padding:9px 12px;font-size:10px}.map-backdrop{z-index:150;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);background:#1d24258f;padding:24px;position:fixed;inset:0}.map-shell{background:#f6f7f4;border-radius:13px;flex-direction:column;width:100%;height:100%;display:flex;overflow:hidden;box-shadow:0 32px 90px #00000040}.map-shell>header{border-bottom:1px solid var(--line);background:#fff;justify-content:space-between;align-items:center;padding:16px 21px;display:flex}.map-shell h2{margin:4px 0 0;font-family:Songti SC,serif;font-size:19px}.map-scroll{background-color:#f1f3f0;background-image:radial-gradient(#c8ceca 1px,#0000 1px);background-size:25px 25px;flex:1;overflow:auto}.map-edge{fill:none;stroke:#93a29f;stroke-width:1.3px}.map-edge-label{fill:#788583;text-anchor:middle;font-size:9px}.map-node{cursor:pointer}.map-node rect{fill:#fff;stroke:#b8c3c0;stroke-width:1.2px;filter:drop-shadow(0 5px 7px #27353214)}.map-node:hover rect,.map-node.active rect{fill:#e8f1ef;stroke:var(--accent);stroke-width:2px}.map-node-title{fill:var(--ink);font-size:12px;font-weight:700}.map-node-meta{fill:var(--muted);font-size:8px}@media (max-width:900px){.app-shell,.app-shell.nav-open{grid-template-columns:56px minmax(0,1fr)}.sidebar{width:56px;transition:width .24s;position:fixed;inset:0 auto 0 0}.nav-open .sidebar{width:292px;box-shadow:15px 0 45px #1c262526}.sidebar-rail{width:56px;min-width:56px}.reader{grid-column:2}.reading-scroll{padding-inline:clamp(22px,7vw,65px)}.drawer-backdrop{z-index:65;background:#1f272726;border:0;display:block;position:fixed;inset:0}.deep-indicator{right:20px}}@media (max-width:620px){.login-page{padding:18px}.login-card{padding:31px 25px 25px}.login-background{width:88vw;top:8%}.app-shell,.app-shell.nav-open{grid-template-columns:48px minmax(0,1fr)}.sidebar{width:48px}.nav-open .sidebar{width:min(292px,100vw - 32px)}.sidebar-rail{width:48px;min-width:48px}.brand-mini,.rail-action,.nav-toggle{width:33px;height:33px}.reader-toolbar{min-height:59px;padding:0 13px}.reader-title span{display:none}.reader-title strong{text-overflow:ellipsis;white-space:nowrap;max-width:120px;display:block;overflow:hidden}.reader-actions button{padding:7px 8px;font-size:9px}.reading-scroll{padding:38px 19px 75px}.lesson h1,.empty-state h1{font-size:36px}.lead{font-size:17px}.prose p{font-size:16px;line-height:1.95}.lesson-meta span:first-child{display:none}.lesson-footer{gap:8px;display:grid}.knowledge-drawer{width:calc(100vw - 24px)}.definition-popover{left:12px!important}.suggestion-list{grid-template-columns:1fr 1fr;display:grid}.suggestion-chip{border-radius:8px;min-width:0}.suggestion-chip span{text-overflow:ellipsis;white-space:nowrap;overflow:hidden}.map-backdrop{padding:7px}}