@import"https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600&family=Noto+Serif+SC:wght@500;600;700&display=swap";:root{font-family:DM Sans,system-ui,sans-serif;color:#24231f;background:#f4f1e9;font-synthesis:none;--ink: #24231f;--muted: #77736a;--paper: #fbfaf6;--line: #ded9ce;--accent: #d95d3f;--accent-soft: #f8e8df;--green: #355e4b}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh}button,input,textarea{font:inherit}button{color:inherit}.app-shell{min-height:100vh;background:radial-gradient(circle at 84% 9%,rgba(217,93,63,.08),transparent 24rem),#f4f1e9}.rail{position:fixed;top:0;left:0;bottom:0;z-index:10;display:flex;width:66px;flex-direction:column;align-items:center;padding-top:24px;gap:10px;border-right:1px solid var(--line);background:#f4f1e9e6;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}.brand-mark{display:grid;width:38px;height:38px;margin:0;place-items:center;color:#fff;background:var(--ink);border-radius:50%;font-family:"Noto Serif SC",serif;font-size:18px}.rail-home{display:grid;place-items:center;padding:0;color:inherit;background:transparent;border:0;cursor:pointer;order:-1;margin-bottom:18px}.rail-home .rail-label{display:none}.rail-button{position:relative;width:38px;height:38px;padding:0;color:var(--muted);background:transparent;border:0;border-radius:9px;cursor:pointer;font-size:19px}.rail-button+.rail-button{margin-top:0}.rail-button:hover{color:var(--ink);background:#e9e5db}.rail-label{display:none}.rail-badge{position:absolute;top:-4px;right:-5px;display:grid;min-width:17px;height:17px;padding:0 4px;place-items:center;color:#fff;background:var(--accent);border-radius:10px;font-size:10px}.workspace{min-height:100vh;margin-left:66px;transition:margin-right .22s ease}.branch-visible .workspace{margin-right:390px}.topbar{display:flex;height:76px;padding:0 5vw;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}.topbar>div{display:flex;align-items:baseline;gap:12px}.topbar strong{font-family:"Noto Serif SC",serif;font-size:21px}.eyebrow,.chapter-label{color:var(--accent);font-size:10px;font-weight:600;letter-spacing:.18em}.ghost-button,.close-button{padding:7px 10px;background:transparent;border:0;border-radius:6px;cursor:pointer}.ghost-button:hover,.close-button:hover{background:#e9e5db}.welcome{display:grid;width:min(1040px,calc(100% - 10vw));min-height:calc(100vh - 76px);margin:0 auto;grid-template-columns:1.05fr .95fr;align-items:center;gap:8vw}.welcome-copy h1{margin:18px 0 22px;font-family:"Noto Serif SC",serif;font-size:clamp(36px,4.2vw,64px);font-weight:600;line-height:1.28;letter-spacing:-.045em}.welcome-copy p{max-width:520px;color:var(--muted);font-size:16px;line-height:1.9}.topic-form{position:relative;padding:34px;background:var(--paper);border:1px solid var(--line);border-radius:3px 26px 3px 3px;box-shadow:0 24px 70px #3a342a17}.topic-form:before{position:absolute;top:-10px;right:28px;width:58px;height:20px;background:#d95d3f47;content:"";transform:rotate(2deg)}.topic-form label{display:block;margin-bottom:18px;font-family:"Noto Serif SC",serif;font-size:19px;font-weight:600}.topic-input-wrap{border-bottom:1px solid var(--ink)}.topic-input-wrap input{width:100%;padding:11px 0 15px;color:var(--ink);background:transparent;border:0;outline:none;font-family:"Noto Serif SC",serif;font-size:20px}.topic-input-wrap button{width:100%;margin:18px 0;padding:13px 18px;color:#fff;background:var(--ink);border:0;border-radius:5px;cursor:pointer}.topic-input-wrap button:disabled{cursor:not-allowed;opacity:.42}.topic-suggestions{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px}.topic-suggestions button{padding:6px 10px;color:var(--muted);background:transparent;border:1px solid var(--line);border-radius:16px;cursor:pointer;font-size:12px}.topic-suggestions button:hover{color:var(--accent);border-color:var(--accent)}.global-error,.branch-error{padding:11px 13px;color:#9a3529;background:#fce8e3;border:1px solid #efc0b6;border-radius:6px}.global-error{grid-column:1 / -1}.reading-layout{width:min(800px,calc(100% - 12vw));margin:0 auto;padding:78px 0 150px}.course-heading{margin-bottom:58px;padding-bottom:36px;border-bottom:1px solid var(--line)}.course-heading h1{margin:12px 0;font-family:"Noto Serif SC",serif;font-size:clamp(38px,6vw,68px);font-weight:600;line-height:1.2;letter-spacing:-.055em}.course-heading p{color:var(--muted)}.course-stream{display:grid;gap:28px}.qa-interval{display:grid;gap:14px;padding:22px 22px 8px;border-left:3px solid var(--accent);background:#fbf6ef}.qa-question p{margin:8px 0 0;font-family:"Noto Serif SC",serif;font-size:20px;line-height:1.6}.qa-note{display:grid;gap:8px}.qa-note span,.qa-answer>.chapter-label{color:var(--muted);font-size:12px;letter-spacing:.08em}.qa-note textarea{width:100%;min-height:92px;padding:14px 16px;resize:vertical;color:var(--ink);border:1px dashed #c9b8a4;border-radius:12px;outline:none;background:#ffffffb8;line-height:1.7}.qa-note textarea:focus{border-style:solid;border-color:var(--green)}.qa-answer{padding-top:4px}.qa-pending{color:var(--muted)}.course{color:#34312c;font-family:"Noto Serif SC",serif;font-size:17px;line-height:2.05}.course h1,.course h2,.course h3{color:var(--ink);line-height:1.45;scroll-margin-top:24px}.course h2{margin:62px 0 18px;font-size:29px}.course h3{margin-top:36px;font-size:21px}.course p,.course li{margin:0 0 17px}.course blockquote{margin:30px 0;padding:16px 22px;color:var(--green);background:#e9efe9;border-left:3px solid var(--green)}.course code{padding:2px 5px;background:#e9e5db;border-radius:4px;font-family:ui-monospace,monospace;font-size:.88em}.course table{display:block;width:100%;margin:28px 0 36px;overflow-x:auto;border-collapse:collapse;font-family:DM Sans,"Noto Serif SC",sans-serif;font-size:14px;line-height:1.65;scrollbar-width:thin}.course thead,.course tbody{display:table;width:100%;min-width:720px;table-layout:fixed}.course th,.course td{padding:12px 14px;vertical-align:top;text-align:left;border:1px solid var(--line);overflow-wrap:anywhere}.course th{color:var(--ink);background:#e9e5db;font-weight:600}.course tr:nth-child(2n) td{background:#f2eee5b8}.message table,.knowledge-card table{display:block;max-width:100%;overflow-x:auto;border-collapse:collapse;font-size:12px}.message th,.message td,.knowledge-card th,.knowledge-card td{padding:7px 8px;text-align:left;border:1px solid var(--line)}.course ::selection{color:var(--ink);background:#f3be82}.mainline-continuation,.learning-resources{margin-top:70px;padding:30px;background:var(--paper);border:1px solid var(--line);border-radius:4px 22px 4px 4px}.mainline-continuation h2,.learning-resources h2{margin:8px 0;font-family:"Noto Serif SC",serif;font-size:28px}.mainline-continuation>p{margin:0 0 20px;color:var(--muted)}.continue-actions{display:flex;flex-wrap:wrap;gap:8px}.continue-actions button,.resource-heading button{padding:8px 12px;color:var(--green);background:#edf1ec;border:1px solid #cad7cf;border-radius:18px;cursor:pointer}.continue-actions button:disabled{cursor:wait;opacity:.5}.continue-custom{display:flex;margin-top:16px;gap:8px}.continue-custom input{min-width:0;flex:1;padding:11px 13px;color:var(--ink);background:#f7f4ed;border:1px solid var(--line);border-radius:6px;outline:none}.continue-custom input:focus{border-color:var(--green)}.continue-custom button{padding:10px 15px;color:#fff;background:var(--ink);border:0;border-radius:6px;cursor:pointer}.continue-custom button:disabled{cursor:not-allowed;opacity:.42}.resource-heading{display:flex;margin-bottom:20px;align-items:flex-start;justify-content:space-between;gap:16px}.resource-list{display:grid;gap:10px}.resource-list>a{display:grid;padding:15px;color:inherit;text-decoration:none;background:#f5f2ea;border:1px solid transparent;border-radius:8px;grid-template-columns:38px 1fr;gap:10px;transition:border-color .12s ease,transform .12s ease}.resource-list>a:hover{border-color:#a6b7ac;transform:translateY(-1px)}.resource-list>a>b{color:var(--accent);font-size:11px;letter-spacing:.08em}.resource-list h3{margin:0 0 5px;font-family:"Noto Serif SC",serif;font-size:16px}.resource-list p{margin:0 0 6px;color:var(--muted);font-size:12px;line-height:1.6}.resource-list span{color:var(--green);font-size:11px}.resource-empty{width:100%;padding:18px;color:var(--muted);background:#f5f2ea;border:1px dashed var(--line);border-radius:8px;cursor:pointer}.library-overlay{position:fixed;top:0;right:0;bottom:0;left:0;z-index:90;background:#23201b38;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px)}.course-library{position:absolute;inset:0 auto 0 66px;width:310px;padding:0 18px 24px;overflow-y:auto;background:var(--paper);border-right:1px solid var(--line);box-shadow:20px 0 55px #23201b21;animation:library-in .16s ease-out}@keyframes library-in{0%{opacity:0;transform:translate(-18px)}}.course-library>header{display:flex;margin:0 -18px 18px;padding:22px 20px;align-items:flex-start;justify-content:space-between;border-bottom:1px solid var(--line)}.course-library h2{margin:4px 0 0;font-family:"Noto Serif SC",serif}.new-course-button{width:100%;padding:10px;color:#fff;background:var(--ink);border:0;border-radius:6px;cursor:pointer}.course-list{display:grid;margin-top:15px;gap:8px}.course-list>p{color:var(--muted);text-align:center}.course-list-item{display:flex;align-items:stretch;background:#f3f0e8;border:1px solid transparent;border-radius:8px}.course-list-item.active{border-color:var(--green)}.course-list-item>button:first-child{min-width:0;padding:12px;flex:1;text-align:left;background:transparent;border:0;cursor:pointer}.course-list-item strong,.course-list-item span{display:block}.course-list-item strong{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.course-list-item span{margin-top:4px;color:var(--muted);font-size:10px}.delete-course{width:36px;color:var(--muted);background:transparent;border:0;cursor:pointer}.selection-action{position:fixed;z-index:50;padding:9px 13px;color:#fff;background:var(--ink);border:0;border-radius:7px;box-shadow:0 8px 24px #231f1938;cursor:pointer;animation:pop-in .12s ease-out}.selection-action span{margin-right:5px;color:#f5ad72}@keyframes pop-in{0%{opacity:0;transform:translateY(5px) scale(.97)}}.branch-panel{position:fixed;inset:0 0 0 auto;z-index:20;display:flex;width:390px;flex-direction:column;background:var(--paper);border-left:1px solid var(--line);box-shadow:-18px 0 50px #3a342a12;animation:slide-in .18s ease-out}@keyframes slide-in{0%{transform:translate(25px);opacity:0}}.branch-panel>header,.cards-drawer>header{display:flex;padding:22px 24px;align-items:flex-start;justify-content:space-between;border-bottom:1px solid var(--line)}.branch-panel h2,.cards-drawer h2{margin:4px 0 0;font-family:"Noto Serif SC",serif;font-size:22px}.close-button{width:34px;height:34px;font-size:24px;line-height:1}.branch-panel>blockquote{margin:18px 24px 4px;padding:12px 14px;color:#5f594f;background:var(--accent-soft);border:0;border-left:3px solid var(--accent);border-radius:4px;font-family:"Noto Serif SC",serif;font-size:13px;line-height:1.65}.branch-messages{flex:1;overflow-y:auto;padding:18px 24px}.message{margin-bottom:16px;line-height:1.7}.message p:first-child{margin-top:0}.message.assistant{padding:15px 16px;background:#f1eee6;border:1px solid #e5dfd3;border-radius:3px 14px 14px}.message.user{margin-left:38px;padding:11px 13px;color:#fff;background:var(--green);border-radius:12px 3px 12px 12px}.save-button{padding:6px 0 0;color:var(--accent);background:transparent;border:0;cursor:pointer;font-size:12px}.save-button.saved{color:var(--green);cursor:default;opacity:.85}.thinking{display:flex;align-items:center;gap:5px;color:var(--muted);font-size:12px}.thinking i{width:5px;height:5px;background:var(--accent);border-radius:50%;animation:pulse .9s infinite alternate}.thinking i:nth-child(2){animation-delay:.2s}.thinking i:nth-child(3){animation-delay:.4s;margin-right:4px}@keyframes pulse{to{opacity:.2;transform:translateY(-3px)}}.follow-up{padding:16px 20px 20px;border-top:1px solid var(--line)}.follow-up textarea{width:100%;padding:10px 12px;resize:none;color:var(--ink);background:#f6f3ec;border:1px solid var(--line);border-radius:7px;outline:none}.follow-up textarea:focus{border-color:#8c877c}.follow-up>div{display:flex;margin-top:8px;align-items:center;justify-content:space-between}.follow-up span{color:var(--muted);font-size:10px}.follow-up button{padding:7px 13px;color:#fff;background:var(--ink);border:0;border-radius:5px;cursor:pointer}.follow-up button:disabled{opacity:.4}.cards-dock{position:fixed;right:24px;bottom:20px;z-index:15;display:flex;padding:10px 14px;align-items:center;gap:8px;color:#fff;background:var(--green);border:0;border-radius:22px;box-shadow:0 9px 28px #22423338;cursor:pointer}.branch-visible .cards-dock{right:414px}.cards-dock b{display:grid;min-width:20px;height:20px;padding:0 5px;place-items:center;color:var(--green);background:#fff;border-radius:10px;font-size:11px}.toast{position:fixed;right:28px;bottom:78px;z-index:120;padding:10px 15px;color:#fff;background:var(--green);border-radius:7px;box-shadow:0 10px 30px #22423340;font-size:13px;animation:pop-in .14s ease-out}.branch-visible .toast{right:414px}.cards-overlay{position:fixed;top:0;right:0;bottom:0;left:0;z-index:100;background:#23201b52;-webkit-backdrop-filter:blur(3px);backdrop-filter:blur(3px)}.cards-drawer{position:absolute;inset:auto 0 0;max-height:76vh;overflow-y:auto;background:var(--paper);border-radius:24px 24px 0 0;box-shadow:0 -20px 70px #23201b29;animation:drawer-up .18s ease-out}@keyframes drawer-up{0%{transform:translateY(30px);opacity:0}}.cards-drawer>header{position:sticky;top:0;z-index:2;background:var(--paper)}.card-grid{display:grid;padding:26px;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px}.knowledge-card{padding:20px;background:#f3f0e8;border:1px solid var(--line);border-radius:4px 18px 4px 4px;line-height:1.65}.knowledge-card small{color:var(--accent)}.knowledge-card h3{margin:8px 0 14px;font-family:"Noto Serif SC",serif}.knowledge-card footer{display:flex;margin-top:16px;padding-top:10px;align-items:center;justify-content:space-between;color:var(--muted);border-top:1px solid var(--line);font-size:11px}.knowledge-card footer button{color:var(--muted);background:transparent;border:0;cursor:pointer}.empty-cards{padding:70px 24px;color:var(--muted);text-align:center}@media(max-width:900px){.welcome{padding:70px 0;grid-template-columns:1fr;gap:48px}.branch-visible .workspace{margin-right:0}.branch-panel{width:min(390px,calc(100vw - 30px))}.branch-visible .cards-dock{display:none}.branch-visible .toast{right:20px;bottom:20px}}@media(max-width:900px){.rail{top:auto;left:0;right:0;bottom:0;z-index:100;width:100%;height:calc(56px + env(safe-area-inset-bottom,0px));padding:4px 8px env(safe-area-inset-bottom,0px);flex-direction:row;justify-content:space-around;align-items:center;gap:0;border-right:0;border-top:1px solid var(--line);background:#fbfaf6fa;box-shadow:0 -8px 24px #24231f0f}.rail-home{display:flex;order:0;min-width:72px;height:48px;margin-bottom:0;flex-direction:column;align-items:center;justify-content:center;gap:2px}.rail-home .brand-mark{width:28px;height:28px;font-size:13px}.rail-home .rail-label,.rail-label{display:block;color:var(--muted);font-size:11px;line-height:1}.rail-button{width:auto;min-width:72px;height:48px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;margin:0;font-size:16px}.rail-badge{top:2px;right:10px}.workspace{margin-left:0;padding-bottom:calc(72px + env(safe-area-inset-bottom,0px))}.topbar{padding:0 20px}.reading-layout{width:calc(100% - 38px);padding-top:50px}.welcome{width:calc(100% - 38px)}.topic-form{padding:24px}.course-library{left:0;width:min(310px,88vw)}.mainline-continuation,.learning-resources{padding:22px 18px}.continue-custom{flex-direction:column}.cards-dock{display:none}.branch-panel{bottom:calc(56px + env(safe-area-inset-bottom,0px));height:auto;max-height:calc(100vh - 56px - env(safe-area-inset-bottom,0px))}.branch-visible .workspace{margin-right:0}}.auth-loading{display:grid;min-height:100vh;place-items:center;color:var(--muted);background:#f4f1e9}.auth-page{display:grid;min-height:100vh;padding:clamp(28px,7vw,96px);grid-template-columns:minmax(0,1fr) minmax(340px,460px);align-items:center;gap:clamp(48px,9vw,140px);background:radial-gradient(circle at 78% 20%,rgba(217,93,63,.1),transparent 25rem),#f4f1e9}.auth-intro .brand-mark{margin:0 0 40px}.auth-intro h1{max-width:760px;margin:18px 0 22px;font-family:"Noto Serif SC",serif;font-size:clamp(42px,5.5vw,74px);line-height:1.16}.auth-intro p{max-width:560px;color:var(--muted);font-size:18px;line-height:1.8}.auth-card{padding:42px;border:1px solid var(--line);border-radius:22px;background:#fbfaf6f0;box-shadow:0 24px 70px #24231f1a}.auth-tabs{display:grid;margin-bottom:34px;grid-template-columns:1fr 1fr;border-bottom:1px solid var(--line)}.auth-tabs button{padding:14px;border:0;border-bottom:2px solid transparent;background:transparent;cursor:pointer}.auth-tabs button.active{color:var(--accent);border-bottom-color:var(--accent);font-weight:600}.auth-card form,.auth-card label{display:grid;gap:10px}.auth-card form{gap:22px}.auth-card label{color:var(--muted);font-size:13px;font-weight:600}.auth-card input{width:100%;padding:14px 16px;color:var(--ink);border:1px solid var(--line);border-radius:10px;outline:none;background:#fff;font-size:15px}.auth-card input:focus{border-color:var(--green);box-shadow:0 0 0 3px #355e4b1a}.auth-submit{padding:15px 18px;color:#fff;border:0;border-radius:10px;background:var(--green);cursor:pointer;font-weight:600}.auth-submit:disabled{opacity:.55;cursor:wait}.auth-error,.save-error{color:#b54832;font-size:13px}.account-actions{display:flex;align-items:center;gap:10px}.account-name{color:var(--muted);font-size:13px}@media(max-width:860px){.auth-page{grid-template-columns:1fr;gap:42px}.auth-intro h1{font-size:42px}.auth-card{padding:28px}.account-name{display:none}}
