:root{color-scheme:light;--navy:#1c3044;--navy-deep:#162839;--ink:#293b4c;--muted:#79818a;--paper:#fffefa;--ground:#eeefeb;--line:#e0e3dd;--brass:#a08a60;--soft:#f3f4f0;--blue-soft:#eef2f5;--serif:"Iowan Old Style","Baskerville","Songti SC","STSong",Georgia,serif;--sans:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-family:var(--sans);font-size:16px;color:var(--ink);background:var(--ground);font-synthesis:none}
*{box-sizing:border-box;min-width:0}
html,body{width:100%;height:100%;margin:0}
body{overflow:hidden;line-height:1.6;-webkit-font-smoothing:antialiased}
button,input,textarea,select{font:inherit;color:inherit}
button{display:inline-flex;align-items:center;justify-content:center;gap:7px;cursor:pointer;transition:background .15s,border-color .15s,color .15s;touch-action:manipulation}
button:disabled{cursor:default;opacity:.42}
button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible,[tabindex]:focus-visible{outline:2px solid #aa936a;outline-offset:3px}
button svg,svg{flex-shrink:0;width:18px;height:18px}
button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}
button{background:none;border:0}
p,h1,h2,h3,h4,figure{margin:0}
a{color:inherit}
[hidden]{display:none!important}
::selection{background:#dfe7e9;color:#152f43}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.study-app{height:100vh;height:100dvh;min-width:1000px;max-width:1920px;margin:0 auto;display:grid;grid-template-rows:68px 112px minmax(0,1fr);overflow:hidden}
.app-header{display:flex;align-items:center;gap:40px;padding:0 26px;background:var(--navy);color:#f4f2e9;border-bottom:1px solid #112334}
.brand{display:flex;align-items:center;gap:12px;flex:none;text-decoration:none}
.brand-mark{width:35px;height:37px;display:grid;place-items:center;border:1px solid #a28e68;border-radius:2px;color:#e4dccb}
.brand-mark svg{width:23px;height:23px}
.brand-name{font-family:var(--serif);font-size:23px;font-weight:600;letter-spacing:2px;line-height:1.25}
.brand-name small{display:block;margin-top:4px;font-family:var(--sans);font-size:8px;letter-spacing:1.6px;color:#b9c0c5;font-weight:400}
.main-nav{display:flex;align-items:stretch;align-self:stretch;gap:28px;font-size:14px;white-space:nowrap}
.main-nav>span,.main-nav>button{display:flex;align-items:center;position:relative;color:#bcc6cc;padding:1px 0 0}
.main-nav>button:hover{color:#fffefa}
.main-nav .nav-current{color:#f4f2e9}
.nav-current:after{content:"";position:absolute;left:0;right:0;bottom:0;height:2px;background:#b69f70}
.header-actions{display:flex;align-items:center;gap:19px;margin-left:auto;white-space:nowrap}
.demo-badge{display:inline-flex;align-items:center;gap:7px;font-size:12px;letter-spacing:.2px;color:#c4cdd2}
.demo-badge>span{width:5px;height:5px;border-radius:50%;background:#bda77b}
.header-info{padding:6px 0;font-size:12px;color:#c4cdd2}
.header-info:hover{color:#fffefa}
.export-preview{display:block;width:calc(100% - 44px);height:min(46vh,400px);margin:0 22px 16px;padding:14px;resize:vertical;border:1px solid var(--line);border-radius:4px;background:var(--paper);font-size:12px;line-height:1.8}
#export-download{text-decoration:none;display:inline-flex}
.button{padding:10px 16px;font-size:14px;font-weight:500;border:1px solid var(--line);border-radius:5px;white-space:nowrap}
.button-header{background:#f3f1e8;color:var(--navy);border-color:#f3f1e8;padding:8px 13px;font-size:13px}
.button-header:hover{background:#fffefa;border-color:#fffefa}
.primary{background:var(--navy);color:#fffefa;border-color:var(--navy)}
.primary:hover{background:#2b455d;border-color:#2b455d}
.course-bar{display:flex;align-items:center;justify-content:space-between;gap:26px;padding:16px 28px 18px}
.course-identity{overflow:hidden}
.course-eyebrow{display:flex;align-items:center;gap:11px;color:#7c857e;font-size:10px;letter-spacing:1.4px;line-height:1.25}
.course-eyebrow>span:first-child{font-size:11px;letter-spacing:.8px;color:#67756e}
.eyebrow-line{width:18px;height:1px;background:#b9c1b8}
h1{font-family:var(--serif);font-weight:600;font-size:26px;letter-spacing:.4px;line-height:1.45;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-top:5px}
.course-meta{color:var(--muted);font-size:12px;line-height:1.5;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-top:3px}
.mode-control{display:flex;align-items:center;gap:14px;flex:none}
.control-label{font-size:12px;color:#7b837e}
.mode-switch{display:flex;border:1px solid #d4d9d3;border-radius:6px;background:#e7eae4;padding:3px;gap:3px;box-shadow:inset 0 1px 2px #243d4710}
.mode-switch button{padding:8px 13px;border-radius:3px;white-space:nowrap;font-size:13px;color:#67746e}
.mode-switch button.active,.mode-switch button[aria-pressed="true"]{background:var(--paper);color:var(--navy);box-shadow:0 1px 4px #1c304415}
.mode-switch button:hover:not(.active){background:#f7f8f280}
.mode-switch svg{width:17px;height:17px}
.workspace{display:grid;grid-template-columns:minmax(0,1.95fr) minmax(340px,1fr);gap:16px;min-height:0;overflow:hidden;padding:0 20px 18px}
.panel{min-height:0;border:1px solid #d9ded6;border-radius:7px;background:var(--paper);box-shadow:0 2px 7px #26372904;overflow:hidden}
.lecture-panel{display:flex;flex-direction:column}
.lecture-toolbar{display:flex;align-items:center;justify-content:space-between;flex:none;min-height:51px;padding:0 15px 0 25px;border-bottom:1px solid var(--line);background:#fffefa}
.content-tabs{display:flex;align-self:stretch;gap:25px}
.content-tabs>button{position:relative;padding:0 0 1px;font-size:13px;color:#899089;white-space:nowrap}
.content-tabs>button:hover{color:var(--navy)}
.content-tabs>button.active,.content-tabs>button[aria-selected="true"]{color:var(--navy);font-weight:600}
.content-tabs>button.active:after,.content-tabs>button[aria-selected="true"]:after{content:"";height:2px;position:absolute;left:0;right:0;bottom:-1px;background:var(--brass)}
.content-tabs svg{width:16px;height:16px}
.lecture-tools{display:flex;align-items:center;gap:12px}
.lecture-status{font-size:10px;letter-spacing:.4px;color:#858c81;padding-left:11px;position:relative;white-space:nowrap}
.lecture-status:before{content:"";position:absolute;left:0;top:50%;width:4px;height:4px;border-radius:50%;background:#a2906d;transform:translateY(-50%)}
.icon-button{height:32px;width:32px;padding:6px;border-radius:4px;color:#7e898a;flex:none}
.icon-button:hover{background:#edf0ea;color:var(--navy)}
.icon-button svg{width:17px;height:17px}
.reader{overflow:auto;overscroll-behavior:contain;flex:1;min-height:0;scrollbar-gutter:stable;scroll-behavior:auto;background:var(--paper)}
.reader:focus-visible{outline-offset:-4px}
.lecture-content{max-width:900px;padding:33px 43px 65px;margin:0 auto;font-size:16px;line-height:1.95;overflow-wrap:anywhere}
.lecture-content p{margin:14px 0;color:#3c4a54}
.lecture-content h2{font-family:var(--serif);font-weight:600;font-size:29px;line-height:1.45;letter-spacing:.5px;color:#20384d;margin:6px 0 14px}
.lecture-content h3{font-family:var(--serif);font-size:23px;font-weight:600;color:#283e50;line-height:1.5;margin:30px 0 13px}
.lecture-content h4{font-size:16px;font-weight:600;line-height:1.6;margin:23px 0 10px}
.lecture-content strong{font-weight:600;color:#293f4f}
.lecture-content ul,.lecture-content ol{padding-left:23px;margin:12px 0 18px}
.lecture-content li{padding-left:3px;margin:6px 0}
.lecture-content li::marker{color:#8e805e}
.lecture-content blockquote{margin:20px 0;padding:9px 18px;border-left:2px solid var(--brass);background:#f6f5ed;color:#647065}
.lecture-content table{width:100%;border-collapse:collapse;font-size:14px;margin:21px 0}
.lecture-content th,.lecture-content td{text-align:left;padding:10px 12px;border:1px solid #e0e3da;vertical-align:top}
.lecture-content th{background:#f2f3ed;font-weight:600}
.lecture-content code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.88em;background:#edf0eb;border-radius:3px;padding:2px 5px}
.lecture-content pre{overflow:auto;padding:16px 20px;border-radius:5px;background:#eff1ec;font-size:14px;line-height:1.8;white-space:pre}
.lecture-content pre code{padding:0;background:none}
.lecture-content hr{border:0;border-top:1px solid var(--line);margin:35px 0}
.lecture-overview,.course-overview,.overview{padding-bottom:29px;border-bottom:1px solid #dfe3d8;margin-bottom:32px}
.article-kicker,.section-kicker,.eyebrow,.overline{font-family:var(--sans);font-size:10px;letter-spacing:1.65px;color:#938261;line-height:1.5;font-weight:500;margin-bottom:8px}
.lecture-content .intro,.lecture-content .overview-intro{color:#798178;font-size:14px;line-height:1.9;margin:10px 0 22px}
.overview-list{list-style:none!important;padding:0!important;margin:22px 0 0!important;display:grid;grid-template-columns:1fr 1fr;column-gap:27px;row-gap:7px;counter-reset:outline}
.overview-list>li{padding:10px 0!important;display:flex;gap:13px;margin:0!important;align-items:flex-start;border-top:1px solid #eceee6;line-height:1.55;counter-increment:outline}
.overview-list>li:before{content:counter(outline,decimal-leading-zero);font-size:11px;color:#a18c66;font-family:var(--serif);padding-top:3px}
.overview-list strong{display:block;font-size:14px;font-weight:500}
.overview-list small,.overview-list .outline-summary,.overview-list li>div>span{display:block;color:#93988d;font-size:11px;line-height:1.65;margin-top:4px}
.overview-list .overview-number{display:none}
.overview-list button{justify-content:flex-start;text-align:left;padding:0;color:inherit;font-size:14px;line-height:1.6}
.overview-list a{text-decoration:none}
.overview-list a:hover,.overview-list button:hover{color:#9a7e4e}
.lecture-section,.lesson-section{position:relative;padding:0 0 30px;scroll-margin-top:23px}
.lecture-section+.lecture-section,.lesson-section+.lesson-section{border-top:1px solid #e5e7de;padding-top:30px;margin-top:10px}
.section-heading,.section-header{display:flex;justify-content:space-between;align-items:center;gap:10px;margin:10px 0 20px}
.section-heading h2,.section-heading h3,.section-header h2,.section-header h3{margin:0}
.quote-button,.ask-paragraph,.ask-section,[data-action="quote"]{color:#8b826c;font-size:11px;white-space:nowrap;gap:5px;border:1px solid #e4e3d9;border-radius:4px;padding:5px 9px;line-height:1.5;flex:none}
.quote-button:hover,.ask-paragraph:hover,.ask-section:hover,[data-action="quote"]:hover{color:var(--navy);background:#f0f2ea;border-color:#cfd7cb}
.quote-button svg{width:13px;height:13px}
.concept-block,.definition-box,.concept-box,.key-concept{padding:16px 21px;background:#f2f4ed;border-left:2px solid #879880;border-radius:0 4px 4px 0;margin:23px 0}
.concept-block p,.definition-box p,.concept-box p,.key-concept p{margin:6px 0}
.concept-label,.box-label{font-size:10px;letter-spacing:1px;color:#7b866f;font-weight:600}
.formula,.formula-block,.equation,.equation-box{padding:17px 20px;margin:20px 0;border:1px solid #e2e5dc;border-radius:4px;text-align:center;background:#f9f9f4;font-family:var(--serif);font-size:21px;color:#233d53;line-height:1.7}
.formula p,.formula-block p,.equation p{margin:0;font-family:var(--serif)}
.formula small,.formula-block small,.equation small{display:block;font-family:var(--sans);font-size:12px;color:var(--muted);margin-top:6px}
.example,.example-box,.example-block{background:#faf7f0;border:1px solid #e9e1d1;border-radius:5px;padding:18px 22px;margin:23px 0}
.example h4,.example-box h4,.example-block h4{margin:0 0 10px;color:#856f46}
.example p,.example-box p,.example-block p{margin:10px 0}
.disclosure,.provenance,.example-disclosure,.source-note{font-size:11px;line-height:1.8;color:#95876b!important}
.pitfall,.pitfall-box,.warning,.note,.note-box,.learning-note,.remember-block,.material-notice,.demo-notice{padding:14px 18px;border:1px solid #e7e4d7;border-radius:4px;background:#f8f7ef;margin:20px 0;color:#7f775f;font-size:14px;line-height:1.85}
.pitfall p,.pitfall-box p,.note p,.note-box p,.learning-note p,.remember-block p,.material-notice p,.demo-notice p{margin:5px 0}
.reading-note,.status-note{font-size:12px;color:#8b917f;padding:10px 0}
.placeholder,.empty-state{padding:36px 18px;text-align:center;font-size:14px;color:#879088}
.empty-state h3{font-family:var(--serif);font-size:22px;color:var(--ink);margin:12px 0}
.empty-state p{margin:8px 0;line-height:1.9}
.source-content{white-space:pre-wrap;overflow-wrap:anywhere;word-break:break-word;max-width:900px;margin:0 auto;padding:32px 40px 64px;font-family:var(--sans);font-size:15px;line-height:2;color:#53616a}
.audio-footer{padding:8px 18px 9px;border-top:1px solid var(--line);background:#f6f7f0;flex:none}
.audio-caption{display:flex;align-items:center;gap:7px;color:#738074;font-size:10px;margin:0 5px 4px}
.audio-caption svg{width:13px;height:13px}
.audio-caption .local-only{margin-left:auto;color:#8e9689}
.audio-footer audio{display:block;width:100%;height:32px}
.chat-panel{display:flex;flex-direction:column;background:#fafbf7}
.chat-header{padding:20px 21px 17px;display:flex;align-items:center;gap:13px;flex:none;background:#fffefa}
.chat-emblem{height:39px;width:39px;display:grid;place-items:center;border:1px solid #d6ddcf;border-radius:4px;color:#51684f;background:#f4f6ef}
.chat-emblem svg{width:22px;height:22px}
.chat-eyebrow{display:block;font-size:8px;letter-spacing:1.7px;line-height:1.5;color:#98a18f;margin-bottom:2px}
.chat-header h2{font-family:var(--serif);font-size:20px;font-weight:600;letter-spacing:.7px;line-height:1.4}
.chat-clear{margin-left:auto;color:#9a9f92}
.chat-scope{display:flex;align-items:center;gap:8px;min-height:32px;padding:5px 23px;border-top:1px solid #edf0e8;border-bottom:1px solid #e6eae0;background:#f1f4ec;color:#718062;font-size:11px;letter-spacing:.25px;flex:none}
.scope-dot{height:4px;width:4px;background:#a2ad91;border-radius:50%}
.chat-messages{min-height:0;flex:1;overflow:auto;overscroll-behavior:contain;scrollbar-gutter:stable;padding:22px 21px 18px;display:flex;flex-direction:column;gap:22px;font-size:15px;line-height:1.9}
.message,.chat-message,.assistant-message,.user-message{max-width:100%;overflow-wrap:anywhere;flex:none}
.message p,.chat-message p,.assistant-message p,.user-message p{margin:8px 0}
.message p:first-child,.chat-message p:first-child,.assistant-message p:first-child,.user-message p:first-child{margin-top:0}
.message p:last-child,.chat-message p:last-child,.assistant-message p:last-child,.user-message p:last-child{margin-bottom:0}
.message.user,.message.student,.chat-message.user,.chat-message.student,.user-message{align-self:flex-end;max-width:93%;padding:12px 16px;border:1px solid #e1e6db;background:#eef2e9;border-radius:6px 6px 1px 6px;color:#3e5443}
.message.assistant,.chat-message.assistant,.assistant-message{padding:0 1px;color:#56616a;white-space:pre-line}
.message-label,.message-meta,.assistant-label{display:flex;align-items:center;gap:6px;margin-bottom:11px;color:#788269;font-size:10px;letter-spacing:.35px;line-height:1.5}
.message-label:before,.assistant-label:before{content:"";width:5px;height:5px;background:#a89974;transform:rotate(45deg)}
.message.system,.chat-message.system,.system-message{align-self:center;border:1px solid #e9e9df;border-radius:4px;padding:9px 12px;color:#929789;font-size:11px;text-align:center;background:#f6f7f0}
.chat-messages code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.9em;padding:2px 4px;background:#eaf0e8;border-radius:3px}
.chat-messages strong{font-weight:600;color:#354d40}
.chat-messages ul,.chat-messages ol{padding-left:20px}
.chat-messages blockquote,.message-quote{border-left:2px solid #b8bea9;margin:0 0 10px;padding:4px 10px;font-size:12px;color:#89927e;background:#f5f7ef}
.citation,.citation-button,[data-action="cite"],[data-action="citation"]{font-size:10px;color:#7e8d77;background:#eff3e9;border:1px solid #e2e8d9;border-radius:3px;line-height:1.5;padding:4px 7px;margin-top:12px;display:inline-flex;gap:5px;align-items:center;text-decoration:none;white-space:normal;text-align:left}
.citation:hover,.citation-button:hover,[data-action="cite"]:hover,[data-action="citation"]:hover{background:#e5ecde;color:#425e3e}
.citation svg{height:12px;width:12px}
.typing,.typing-indicator,.loading{display:inline-flex;align-items:center;gap:5px;color:#919a87;font-size:12px;line-height:1.8}
.typing span,.typing-indicator span,.loading-dot{width:4px;height:4px;border-radius:50%;background:#a6af98;animation:breathe 1.3s infinite ease-in-out}
.typing span:nth-child(2),.typing-indicator span:nth-child(2){animation-delay:.16s}
.typing span:nth-child(3),.typing-indicator span:nth-child(3){animation-delay:.32s}
@keyframes breathe{0%,80%,100%{opacity:.3;transform:translateY(0)}40%{opacity:1;transform:translateY(-2px)}}
.composer-area{padding:12px 17px 10px;background:#fffefa;border-top:1px solid #e2e6dc;flex:none}
.quick-prompts{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:11px}
.quick-prompts button{padding:4px 8px;border:1px solid #e1e5d9;border-radius:4px;color:#6c7a5b;font-size:11px;line-height:1.6;background:#fafbf6;white-space:nowrap}
.quick-prompts button:hover{border-color:#bdc9b1;background:#f1f5eb;color:#4f6647}
.chat-form{border:1px solid #d7decf;border-radius:5px;background:#fdfefa;overflow:hidden;transition:border-color .15s,box-shadow .15s}
.chat-form:focus-within{border-color:#a5b29a;box-shadow:0 0 0 2px #a5b29a12}
#question-input{display:block;border:0;resize:none;outline:none;box-shadow:none;background:transparent;width:100%;min-height:71px;max-height:120px;padding:12px 13px 2px;color:#435342;font-size:14px;line-height:1.75}
#question-input::placeholder{color:#7c8972}
.composer-footer{display:flex;align-items:center;gap:7px;padding:5px 8px 8px 12px}
.composer-footer>span{font-size:10px;letter-spacing:-.15px;color:#859078;white-space:nowrap;margin-right:auto}
.send-button{background:#263f39;color:#f7f9f1;border-radius:4px;font-size:11px;padding:6px 9px;line-height:1.5}
.send-button svg{width:14px;height:14px}
.send-button:not(:disabled):hover{background:#39594d}
.stop-button{background:#f0f2e9;color:#6e7c61;border:1px solid #dbe2d2;font-size:11px;padding:5px 8px;border-radius:4px}
.stop-button>span{width:7px;height:7px;background:#7a876d}
.reading-assurance{display:flex;align-items:center;justify-content:center;gap:5px;margin-top:8px;font-size:10px;color:#7c896d;line-height:1.5;letter-spacing:.3px}
.reading-assurance svg{width:12px;height:12px}
.quote-context{display:flex;align-items:flex-start;gap:8px;margin:10px 11px 0;padding:8px 8px 8px 10px;background:#f0f4e9;border-left:2px solid #a1b08e;max-height:95px;overflow:auto}
.quote-context>div{flex:1;overflow:hidden}
.quote-label{font-size:9px;color:#899b77;letter-spacing:.3px}
.quote-context p{font-size:11px;line-height:1.7;color:#76866a;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;margin-top:2px}
.quote-context .icon-button{height:23px;width:23px;padding:3px;color:#94a185}
.dialog{border:1px solid #d4dacf;border-radius:9px;background:var(--paper);color:var(--ink);padding:0;width:min(660px,calc(100vw - 48px));max-height:calc(100dvh - 56px);overflow:auto;box-shadow:0 22px 100px #0b223b30;scrollbar-gutter:stable}
.dialog::backdrop{background:#172b3e70;backdrop-filter:blur(4px)}
.dialog-heading{display:flex;align-items:flex-start;justify-content:space-between;gap:20px;padding:27px 30px 24px;border-bottom:1px solid var(--line);background:#fbfbf5}
.dialog-kicker{font-size:9px;letter-spacing:1.7px;color:#9e8c66;line-height:1.4}
.dialog-heading h2{font-family:var(--serif);font-size:27px;font-weight:600;line-height:1.4;letter-spacing:.7px;margin-top:7px}
.dialog-heading p{margin-top:8px;font-size:12px;color:#8f9586}
.dialog-heading .close-dialog{margin-top:-3px;margin-right:-9px}
.upload-form{padding:23px 30px 0}
.form-field{margin-bottom:23px}
.form-field>label,.paste-label{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:500;margin-bottom:8px;color:#52614d}
.form-field>label>span,.optional-label{font-size:10px;color:#a4ab9a;font-weight:400}
input[type="text"],select,#pasted-text-input{background:#fffefa;border:1px solid #dbe0d5;border-radius:4px;padding:10px 11px;width:100%;font-size:13px;line-height:1.6}
input::placeholder,textarea::placeholder{color:#a6ad9d}
fieldset{padding:0;margin:0 0 23px;border:0;min-inline-size:0}
legend{display:flex;align-items:center;gap:8px;padding:0;font-size:13px;font-weight:500;color:#52614d}
.field-number{font-family:var(--serif);font-size:13px;color:#a5936b;padding-right:3px}
.field-help{font-size:12px;line-height:1.8;color:#7d896f;margin:5px 0 11px}
.file-drop{display:flex;align-items:center;gap:15px;flex-wrap:wrap;background:#f5f7f0;border:1px dashed #cbd5be;padding:18px 17px;border-radius:5px;cursor:pointer}
.file-drop>svg{width:29px;height:29px;color:#8d9e7a}
.file-drop strong{font-size:13px;display:block;font-weight:500;color:#5f7451}
.file-drop small{font-size:10px;color:#a3ae97;display:block;margin-top:3px}
.file-choose{margin-left:auto;border:1px solid #d4ddc9;border-radius:4px;padding:5px 9px;color:#8b9b79;font-size:11px;background:#fffefa}
.file-drop:hover{border-color:#aabf95;background:#eff5e9}
.file-drop input{width:100%;font-size:11px;color:#8c9c7a;line-height:1.6}
input[type="file"]::file-selector-button{border:1px solid #d4ddc9;background:#fffefa;color:#7d9068;border-radius:4px;padding:5px 10px;margin-right:10px;font:inherit;cursor:pointer}
#main-file-input{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}
.file-drop:focus-within{outline:2px solid #aa936a;outline-offset:3px}
.selected-file-info{font-size:11px;color:#8b987d;line-height:1.8;overflow-wrap:anywhere}
.selected-file-info:not(:empty){padding:7px 1px 4px}
.paste-label{font-size:11px;font-weight:400;color:#929d87;margin-top:11px;margin-bottom:6px}
#pasted-text-input{display:block;resize:vertical;min-height:85px;max-height:190px;font-size:12px;line-height:1.8}
.supplementary-field{padding-top:17px;border-top:1px solid #eceee5}
#supplement-file-input{width:100%;font-size:11px;color:#929e86}
.subject-field .field-help{margin-bottom:0}
.subject-field select{font-size:12px}
.mode-fieldset legend{margin-bottom:10px}
.upload-mode-options{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.mode-option{display:flex;align-items:flex-start;gap:9px;border:1px solid #e0e5d7;padding:13px;border-radius:4px;cursor:pointer;background:#fbfcf6}
.mode-option:has(input:checked){border-color:#9aac88;background:#f1f5e9}
.mode-option input{margin:3px 0 0;accent-color:#5b7450;width:14px;height:14px;flex:none}
.mode-option strong{display:block;font-size:12px;font-weight:500;color:#667d55;line-height:1.5}
.mode-option small{display:block;font-size:10px;color:#7d8e6b;line-height:1.7;margin-top:4px}
.upload-note{display:flex;gap:9px;padding:12px 14px;background:#f6f4eb;border:1px solid #e8e3d2;border-radius:4px;color:#88784f;font-size:12px;line-height:1.8}
.upload-note svg{width:15px;height:15px;margin-top:2px;color:#b3a57f}
.upload-status{font-size:12px;line-height:1.8;color:#8a7854;overflow-wrap:anywhere}
.upload-status:not(:empty){margin-top:12px}
.dialog-footer{display:flex;align-items:center;justify-content:space-between;gap:15px;padding:21px 30px;border-top:1px solid var(--line);margin-top:23px;background:#fbfcf6}
.upload-form>.dialog-footer{margin-left:-30px;margin-right:-30px}
.text-button{font-size:11px;color:#93a07f;padding:5px 0}
.text-button:hover{color:#536f43}
.library-list{padding:18px 24px 6px;display:flex;flex-direction:column;gap:10px}
.library-item,.course-card,.saved-course{padding:15px 17px;border:1px solid #e2e7d9;border-radius:5px;background:#fcfdf7;display:flex;gap:13px;align-items:center;text-align:left;width:100%;color:#6f7e61}
.library-item:hover,.course-card:hover,.saved-course:hover{border-color:#bacaaa;background:#f3f8eb}
.library-item>div,.course-card>div,.saved-course>div{flex:1}
.library-item strong,.course-card strong,.saved-course strong{display:block;font-size:14px;font-weight:500;color:#4e6543;line-height:1.7}
.library-item small,.course-card small,.saved-course small,.library-meta{display:block;font-size:10px;line-height:1.7;color:#a4b194;margin-top:5px}
.library-item .button,.course-card .button{font-size:11px;padding:6px 9px}
.library-item .icon-button{color:#aab69b}
.library-item.current,.course-card.current{border-color:#a9bd96;background:#f0f6e7}
.library-note{padding:6px 28px 0;font-size:10px;color:#a8b299;line-height:1.8}
.library-dialog .dialog-footer{margin-top:18px}
.about-dialog{width:min(590px,calc(100vw - 48px))}
.about-content{padding:22px 30px 0}
.about-intro{font-size:14px;line-height:1.9;color:#718268;margin-bottom:24px}
.about-item{display:flex;gap:17px;margin:20px 0}
.about-item>span{font-family:var(--serif);color:#b3a17a;font-size:15px;padding-top:1px}
.about-item h3{font-size:13px;color:#627957;font-weight:500;line-height:1.8}
.about-item p{font-size:13px;line-height:1.9;color:#79886b;margin-top:4px}
.privacy-note{background:#f3f6ec;border:1px solid #e2e8d7;border-radius:4px;padding:11px 14px;color:#768866;font-size:12px;line-height:1.9;margin-top:23px}
.about-dialog .dialog-footer{justify-content:flex-end}
.toast{position:fixed;left:50%;bottom:25px;transform:translateX(-50%);max-width:min(600px,calc(100vw - 36px));padding:11px 19px;background:#203a35;color:#f0f5e9;border:1px solid #446053;border-radius:5px;box-shadow:0 5px 20px #18302f18;font-size:12px;line-height:1.8;z-index:20;overflow-wrap:anywhere}
.lecture-intro{padding:0 0 29px;margin:0 0 34px;border-bottom:1px solid #dfe3d8}
.lecture-intro>.eyebrow{display:block;margin-bottom:9px;color:#917b52;font-size:10px;letter-spacing:1.6px;line-height:1.5}
.lecture-intro>h2{margin:0 0 11px;font-size:30px;letter-spacing:1px}
.lecture-intro>p{font-size:14px;color:#7b8575;line-height:1.9;margin:0 0 22px}
.lecture-content .knowledge-outline{counter-reset:knowledge;list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));column-gap:25px;row-gap:0}
.lecture-content .knowledge-outline>li{counter-increment:knowledge;position:relative;display:grid;grid-template-columns:23px minmax(0,1fr);column-gap:7px;align-content:start;padding:13px 0 12px;margin:0;border-top:1px solid #e7eade;line-height:1.6}
.knowledge-outline>li:before{content:counter(knowledge,decimal-leading-zero);grid-column:1;grid-row:1/span 2;font-family:var(--serif);font-size:12px;color:#a38c61;padding-top:2px}
.knowledge-outline>li>strong{grid-column:2;font-family:var(--sans);font-size:14px;font-weight:500;color:#455b44;line-height:1.65}
.knowledge-outline>li>span{grid-column:2;margin-top:5px;font-size:11px;line-height:1.75;color:#89937d}
.knowledge-outline>li:last-child:nth-child(odd){grid-column:1/-1}
.lesson-section .section-header{margin:0 0 12px;min-height:27px}
.section-number{display:block;font-size:10px;font-weight:500;color:#978359;letter-spacing:1.25px;line-height:1.5;font-family:var(--sans)}
.lesson-section>.section-number{margin-bottom:14px}
.lesson-section>h2{font-size:27px;line-height:1.5;margin:0 0 20px;letter-spacing:.2px}
.lecture-content .section-lead{font-size:16px;line-height:1.95;color:#7a866f;margin:0 0 26px;padding:0 0 17px;border-bottom:1px solid #edf0e5}
.lecture-content .note-box{border-color:#e1e5d5;border-left:2px solid #a5ae8f;background:#f5f6ed;padding:14px 18px;margin:24px 0}
.note-box>strong:first-child{display:block;font-size:11px;font-weight:500;letter-spacing:.6px;color:#8c926d;margin-bottom:6px}
.lecture-content .note-box>p{font-size:14px;line-height:1.9;color:#737e66;margin:6px 0 0}
.example-card{margin:25px 0;padding:18px 21px;border:1px solid #e8e0cc;border-left:2px solid #b49a66;border-radius:0 4px 4px 0;background:#fbf8ef}
.example-card>strong:first-child{display:block;font-size:11px;line-height:1.8;letter-spacing:.3px;font-weight:500;color:#a08b60;margin-bottom:10px}
.lecture-content .example-card>p{font-size:14px;line-height:1.95;color:#716e5c;margin:12px 0}
.lecture-content .example-card>p:last-child{margin-bottom:0;padding-top:10px;border-top:1px solid #ebe5d6;font-size:11px;line-height:1.9;color:#9a8d70}
.material-summary{display:grid;grid-template-columns:83px minmax(0,1fr);margin:24px 0 27px;border-top:1px solid #e2e8d9;border-bottom:1px solid #e2e8d9;font-size:14px;line-height:1.85;background:#fafbf5}
.material-summary dt,.material-summary dd{margin:0;padding:13px 16px;border-bottom:1px solid #e9ede1;overflow-wrap:anywhere}
.material-summary dt{font-size:11px;color:#8c9c7b;font-weight:500;padding-right:3px}
.material-summary dd{color:#5e7450;font-size:13px;padding-left:11px}
.material-summary dt:nth-last-of-type(1),.material-summary dd:last-child{border-bottom:0}
.notice{background:#f4f7ec;border:1px solid #dde6cd;border-radius:4px;margin:23px 0;padding:17px 20px;font-size:14px;line-height:1.9;color:#7e906b}
.notice>strong{display:block;font-size:13px;font-weight:500;color:#6b8257;margin-bottom:6px}
.lecture-content .notice>p{font-size:13px;line-height:1.9;color:#8b9c78;margin:6px 0 0}
.secondary-button{padding:9px 14px;min-height:39px;border:1px solid #cad8bb;border-radius:4px;background:#f2f7e9;color:#698453;font-size:12px;font-weight:500;line-height:1.6;white-space:nowrap}
.secondary-button:hover{background:#eaf3dc;border-color:#afc596;color:#506f39}
.library-course{position:relative;display:flex;flex-direction:column;align-items:stretch;justify-content:center;gap:6px;width:100%;padding:17px 42px 17px 19px;border:1px solid #dce5d1;border-radius:5px;background:#fcfdf7;text-align:left;line-height:1.7}
.library-course:after{content:"↗";position:absolute;right:18px;top:50%;transform:translateY(-50%);color:#a9ba94;font-size:17px}
.library-course>strong{display:block;color:#567647;font-size:15px;font-weight:500;line-height:1.7}
.library-course>span{display:block;color:#91a27f;font-size:11px;line-height:1.75}
.library-course:hover{border-color:#b4c99c;background:#f2f8e9}
.library-course:hover:after{color:#6f8d56}
.welcome-message{padding:0 0 18px!important;border-bottom:1px solid #e8ecdf;color:#7a8a6c!important}
.welcome-message>p{font-size:14px;line-height:1.95}
.assistant-message blockquote,.user-message blockquote{white-space:pre-wrap;font-size:12px;line-height:1.8;overflow-wrap:anywhere}
.user-message blockquote{background:#e8eede;border-left-color:#a2b18b;color:#809369;margin:0 0 10px;padding:6px 10px}
.lecture-content blockquote>p{font-size:14px;line-height:1.9;margin:5px 0;color:#7e866f}
::-webkit-scrollbar{width:6px;height:6px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:#d6dbcf;border-radius:5px;border:1px solid transparent;background-clip:padding-box}
::-webkit-scrollbar-thumb:hover{background:#b8c3ab}
@media(min-width:1550px){.workspace{grid-template-columns:minmax(0,2fr) minmax(400px,1fr);padding-left:28px;padding-right:28px;gap:20px}.lecture-content{padding:40px 60px 80px;font-size:17px}.course-bar{padding-left:37px;padding-right:37px}.chat-messages{font-size:15px;padding-left:26px;padding-right:26px}.composer-area{padding-left:23px;padding-right:23px}.chat-header{padding-left:26px;padding-right:26px}}
@media(max-width:1150px){.app-header{gap:28px;padding-left:21px;padding-right:21px}.header-actions{gap:13px}.main-nav{gap:21px}.brand-name{font-size:21px}.header-info{display:none}.course-bar{padding-left:24px;padding-right:24px;gap:16px}h1{font-size:24px}.control-label{display:none}.workspace{gap:12px;padding-left:14px;padding-right:14px}.lecture-content{padding-left:31px;padding-right:31px}.lecture-toolbar{padding-left:21px}.content-tabs{gap:19px}.lecture-status{font-size:9px}.chat-messages{padding-left:17px;padding-right:17px}.composer-area{padding-left:13px;padding-right:13px}.quick-prompts{gap:5px}.quick-prompts button{font-size:9px}.composer-footer>span{font-size:8px}}
@media(max-height:760px){.study-app{grid-template-rows:60px 100px minmax(0,1fr)}.app-header{padding-top:0;padding-bottom:0}.brand-name{font-size:21px}.brand-name small{font-size:7px}.brand-mark{height:32px;width:31px}.course-bar{padding-top:12px;padding-bottom:13px}h1{font-size:25px}.lecture-content{padding-top:27px}.chat-header{padding-top:15px;padding-bottom:14px}.composer-area{padding-top:10px;padding-bottom:8px}.quick-prompts{margin-bottom:8px}#question-input{min-height:65px}.dialog{max-height:calc(100dvh - 32px)}}
@media(max-height:620px){.study-app{grid-template-rows:54px 86px minmax(0,1fr)}.course-bar{padding-top:9px;padding-bottom:10px}.course-eyebrow{font-size:8px}.course-meta{font-size:10px}h1{font-size:22px}.chat-header{padding-top:12px;padding-bottom:11px}.chat-eyebrow{display:none}.chat-header h2{font-size:18px}.chat-emblem{width:31px;height:31px}.lecture-toolbar{min-height:45px}.chat-scope{min-height:28px;font-size:9px}.reading-assurance{display:none}.quick-prompts{display:none}.composer-area{padding:9px 13px}#question-input{min-height:54px}.workspace{padding-bottom:11px}}
@media(max-width:999px){body{overflow-x:auto}.study-app{width:1000px;margin:0}.dialog{position:fixed;width:min(660px,calc(100vw - 32px));min-width:0}.toast{left:16px;transform:none;max-width:calc(100vw - 32px)}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation:none!important;transition:none!important}}