@import "https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@400;500;600;700;800&display=swap";
:root{--ink:#183535;--muted:#71817b;--green:#176551;--green-dark:#124d40;--line:#dfe7e0;--paper:#fbfcf8;--wash:#f0f4ed;--font:"Noto Sans KR",Arial,sans-serif}*{box-sizing:border-box}html{scroll-behavior:smooth}body{font-family:var(--font);color:var(--ink);background:var(--paper);margin:0;font-size:14px}a{color:inherit;text-decoration:none}button,input,textarea,select{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{opacity:.5;cursor:not-allowed}button{color:inherit}button:focus-visible,a:focus-visible{outline-offset:4px;outline:3px solid #dbb76a}input:focus,textarea:focus,select:focus{outline-offset:2px;outline:2px solid #72a794}input,textarea,select{max-width:100%}button svg,a svg{flex-shrink:0}.brand{letter-spacing:-1px;align-items:center;gap:10px;font-size:24px;font-weight:800;line-height:1;display:inline-flex}.brand-icon{background:var(--green);color:#fff;border-radius:14px;place-items:center;width:43px;height:43px;display:grid}.brand-ai{color:#5c8e77}.brand small{letter-spacing:1.8px;color:var(--muted);margin-top:7px;font-size:10px;font-weight:500;display:block}.button{background:var(--green);color:#fff;border:1px solid #0000;border-radius:8px;justify-content:center;align-items:center;gap:14px;padding:15px 23px;font-size:14px;font-weight:600;transition:background .2s;display:inline-flex}.button:hover{background:var(--green-dark)}.button.small{padding:11px 17px;font-size:12px}.button.secondary{border-color:var(--line);color:var(--green);background:#fff}.button.full{width:100%}.text-link{color:var(--green);background:0 0;border:0;align-items:center;gap:8px;padding:0;font-size:13px;display:inline-flex}.topbar{border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;max-width:1232px;height:102px;margin:auto;padding:0 24px;display:flex}.topbar nav{align-items:center;gap:35px;font-size:13px;display:flex}.landing main{max-width:1232px;margin:auto;padding:0 24px}.hero{grid-template-columns:1.12fr 1fr;align-items:center;gap:62px;padding:90px 0 95px;display:grid}.eyebrow{color:#5a806e;letter-spacing:2px;align-items:center;gap:8px;font-size:10px;font-weight:700;display:flex}.eyebrow span{background:#5c9175;border-radius:50%;width:6px;height:6px}h1,h2,h3,p{margin-top:0}h1{letter-spacing:-2.8px;margin:25px 0 22px;font-size:49px;font-weight:700;line-height:1.42}h1 em{color:var(--green);font-style:normal}.hero-description{color:var(--muted);letter-spacing:-.4px;font-size:16px;line-height:1.9}.hero-actions{align-items:center;gap:25px;margin-top:34px;display:flex}.hero-note{color:#89968b;align-items:center;gap:7px;margin-top:20px;font-size:11px;display:flex}.study-card{background:#fff;border:1px solid #d8e2d6;border-radius:17px;padding:25px 29px;transform:rotate(1deg);box-shadow:0 20px 65px #355b3420}.card-top{color:var(--muted);border-bottom:1px solid #e9eee7;align-items:center;gap:7px;padding-bottom:18px;font-size:11px;display:flex}.dot{background:#83a58e;border-radius:50%;width:6px;height:6px}.sample-badge{background:var(--wash);border-radius:4px;margin-left:auto;padding:4px 7px;font-size:10px}.sample-question{background:#f1f4ee;border-radius:12px 12px 2px;margin:22px 0 20px 52px;padding:14px 18px;font-size:16px;font-weight:500;line-height:1.7}.sample-answer{gap:12px;font-size:12px;line-height:1.9;display:flex}.sample-answer strong{font-size:12px}.sample-answer p{color:#6b7a72;margin:7px 0}.tiny-icon{width:28px;height:28px;color:var(--green);background:#e9f1e8;border-radius:8px;flex-shrink:0;place-items:center;display:grid}.stars-diagram{background:#fafaf4;border-radius:10px;justify-content:center;align-items:center;gap:36px;margin:18px 0 16px 40px;padding:20px;display:flex}.stars-diagram>div{flex-direction:column;align-items:center;gap:5px;font-size:10px;display:flex}.stars-diagram b{margin-top:6px;font-weight:500}.stars-diagram small{color:#7d8678}.star{background:radial-gradient(circle at 40% 35%,#fae6a5,#e6af50);border-radius:50%;display:block;box-shadow:0 0 18px #f5d49450}.star-small{width:34px;height:34px;margin:17px 0}.star-large{width:68px;height:68px}.diagram-arrow{color:#a3aea0}.concept-line{color:#75836d;align-items:center;gap:10px;margin-left:40px;font-size:10px;display:flex}.concept-line strong{color:#55754f}.concept-line>span{background:#f1f4ec;border-radius:3px;margin-left:auto;padding:3px 6px;font-size:9px}.how-section{border-top:1px solid var(--line);padding-top:42px}.section-heading h2{letter-spacing:-1px;margin:13px 0 8px;font-size:27px}.section-heading>p{color:var(--muted);font-size:13px}.feature-grid{grid-template-columns:repeat(3,1fr);gap:22px;margin-top:26px;display:grid}.feature-grid article{border:1px solid var(--line);background:#fff;border-radius:11px;padding:24px;position:relative}.feature-grid svg{color:#628572;width:22px}.feature-grid h3{letter-spacing:-.3px;margin:20px 0 10px;font-size:15px}.feature-grid p{color:var(--muted);margin:0;font-size:12px;line-height:1.9}.step{color:#afbdae;font-size:13px;position:absolute;top:22px;right:25px}.early-note{color:var(--muted);margin:27px 0 45px;font-size:11px;line-height:1.8}.early-note span{color:#668472;margin-right:13px;font-weight:600}footer{border-top:1px solid var(--line);align-items:center;gap:30px;max-width:1184px;margin:auto;padding:27px 0;display:flex}footer .brand{font-size:17px}footer .brand-icon{border-radius:10px;width:32px;height:32px}footer .brand small{font-size:8px}footer p{color:var(--muted);margin:0;font-size:11px}footer>small{color:var(--muted);margin-left:auto;font-size:10px}.auth-page{grid-template-columns:1fr 1fr;min-height:100dvh;display:grid}.auth-intro{background:#edf2e8;flex-direction:column;justify-content:space-between;padding:55px 70px;display:flex}.auth-intro h1{font-size:48px}.auth-intro p{color:var(--muted);font-size:17px;line-height:1.9}.auth-form{width:100%;max-width:440px;margin:auto;padding:60px 35px}.auth-icon{color:var(--green);width:30px;height:30px;margin-bottom:22px}.auth-form h2{letter-spacing:-1px;margin-bottom:12px;font-size:27px}.auth-form>p{color:var(--muted);font-size:12px;line-height:1.8}.auth-form form{margin-top:26px}.auth-form label{margin-bottom:18px;font-size:12px;font-weight:600;display:block}.auth-form input{border:1px solid var(--line);background:#fff;border-radius:7px;width:100%;margin-top:9px;padding:13px 14px;font-weight:400;display:block}.auth-switch{justify-content:space-between;margin-top:10px;display:flex}.auth-switch button{color:var(--muted);background:0 0;border:0;font-size:11px}.form-status{color:var(--green);margin:14px 0;font-size:12px;line-height:1.8}.notice{color:#637653;background:#eff4e9;border:1px solid #dce6d3;border-radius:8px;padding:13px 15px;font-size:12px;line-height:1.8}.notice.compact{padding:8px 13px}.muted{color:var(--muted);font-size:12px;line-height:1.8}.center-state{text-align:center;flex-direction:column;justify-content:center;align-items:center;gap:18px;min-height:100dvh;padding:30px;display:flex}.center-state h1{letter-spacing:-1px;margin:12px 0;font-size:28px}.center-state p{color:var(--muted);line-height:1.8}.workspace{grid-template-columns:267px minmax(0,1fr);height:100dvh;display:grid;overflow:hidden}.sidebar{border-right:1px solid var(--line);background:#f0f3ec;flex-direction:column;min-height:0;padding:27px 19px 17px;display:flex}.sidebar .brand{font-size:22px}.sidebar .brand-icon{width:37px;height:37px}.new-chat{justify-content:flex-start;width:100%;margin:34px 0 25px;padding:12px 15px}.sidebar-label{color:#83907c;justify-content:space-between;align-items:center;margin-bottom:12px;padding:0 7px;font-size:11px;display:flex}.sidebar-label button,.account>button{color:#7a8b77;background:0 0;border:none;padding:3px}.thread-list{flex:1;min-height:0;overflow:auto}.thread{text-align:left;background:0 0;border:none;border-radius:7px;align-items:flex-start;gap:8px;width:100%;margin-bottom:4px;padding:12px 8px;font-size:12px;display:flex}.thread.active{color:#285639;background:#e1e9da}.thread:hover{background:#e6ecdf}.thread>svg{color:#849580;flex-shrink:0;margin-top:2px}.thread>span{text-overflow:ellipsis;white-space:nowrap;flex:1;min-width:0;overflow:hidden}.thread small{color:#909a8b;margin-top:5px;font-size:10px;display:block}.thread i{background:#bd9148;border-radius:50%;flex-shrink:0;width:6px;height:6px;margin-top:5px}.account{border-top:1px solid var(--line);align-items:center;gap:10px;padding-top:17px;display:flex}.avatar{color:#4c6744;background:#dde7d3;border-radius:50%;flex-shrink:0;place-items:center;width:33px;height:33px;font-size:12px;display:grid}.account strong{font-size:11px}.account small{color:#8a9683;margin-top:3px;font-size:10px;display:block}.account>button{margin-left:auto}.chat-main{background:#fdfefb;flex-direction:column;min-width:0;min-height:0;display:flex}.chat-header{border-bottom:1px solid #e9ede5;justify-content:space-between;align-items:center;gap:20px;padding:24px 40px;display:flex}.chat-header h2{letter-spacing:-.5px;white-space:nowrap;text-overflow:ellipsis;max-width:65vw;margin:8px 0 0;font-size:16px;overflow:hidden}.chat-header .eyebrow{font-size:8px}.status-pill{white-space:nowrap;color:#7f9075;border:1px solid #e2e8dc;border-radius:20px;align-items:center;gap:6px;padding:6px 10px;font-size:10px;display:flex}.status-pill>span{background:#91a875;border-radius:50%;width:5px;height:5px}.chat-scroll{flex:1;min-height:0;padding:25px 34px;overflow:auto}.chat-welcome{text-align:center;flex-direction:column;align-items:center;max-width:650px;margin:35px auto 0;display:flex}.welcome-icon{color:#709362;background:#edf2e6;border-radius:21px;place-items:center;width:64px;height:64px;margin-bottom:28px;display:grid}.chat-welcome h1{letter-spacing:-1.7px;margin:17px 0;font-size:37px;line-height:1.45}.chat-welcome p{color:#8a9583;font-size:13px;line-height:1.9}.chat-welcome .eyebrow{font-size:8px}.suggestions{flex-direction:column;gap:8px;width:100%;max-width:425px;margin-top:20px;display:flex}.suggestions button{text-align:left;color:#65765b;background:#fff;border:1px solid #e4eadf;border-radius:8px;justify-content:space-between;align-items:center;gap:15px;padding:13px 16px;font-size:12px;display:flex}.suggestions svg{color:#9dac92;flex-shrink:0;transform:rotate(45deg)}.composer-wrap{width:100%;max-width:865px;margin:auto;padding:10px 34px 18px}.composer{background:#fff;border:1px solid #d4dfcb;border-radius:12px;padding:12px 17px;box-shadow:0 4px 16px #274d1910}.composer-top{color:#87977b;align-items:center;gap:7px;display:flex}.composer-top select{color:#617653;background:0 0;border:none;padding:4px 6px;font-size:11px}.composer-top>span{color:#a0aa98;margin-left:auto;font-size:9px}.composer textarea{resize:vertical;width:100%;min-height:72px;max-height:220px;color:var(--ink);border:0;padding:14px 0 3px;font-size:13px;line-height:1.7}.composer textarea:focus{outline:none}.composer textarea::placeholder{color:#a1ac99}.composer-bottom{justify-content:space-between;align-items:center;display:flex}.composer-bottom small{color:#a1ac99;font-size:9px}.send-button{background:var(--green);color:#fff;border:none;border-radius:9px;place-items:center;width:34px;height:34px;display:grid}.composer-hint{color:#9ba690;text-align:center;margin:12px 0 0;font-size:10px;line-height:1.7}.message-list{max-width:755px;margin:auto}.message{margin-bottom:26px;font-size:14px;line-height:1.95}.message-label{color:#71876b;margin-bottom:8px;font-size:10px;font-weight:600}.message-content{white-space:pre-wrap;overflow-wrap:anywhere}.message.user{background:#eff3e9;border-radius:12px 12px 2px;margin-left:15%;padding:16px 20px}.message.assistant,.message.teacher{padding:12px 8px}.message.teacher{background:#f4f7ef;border-left:3px solid #a0b587;padding-left:18px}.source-line{color:#839477;flex-wrap:wrap;align-items:center;gap:6px;margin-top:12px;font-size:10px;display:flex}.review-note{color:#a08145;background:#fcf8ec;border-radius:7px;align-items:center;gap:8px;padding:12px;font-size:11px;display:flex}.thinking{color:#849574;align-items:center;gap:9px;max-width:755px;margin:20px auto;font-size:12px;display:flex}.spin{animation:1s linear infinite spin}@keyframes spin{to{transform:rotate(360deg)}}.teacher-nav{flex-direction:column;gap:7px;margin-bottom:20px;display:flex}.teacher-nav button{text-align:left;background:0 0;border:0;border-radius:7px;align-items:center;gap:10px;padding:10px;font-size:12px;display:flex}.teacher-nav .selected{background:#e1e9da}.teacher-nav span{margin-left:auto;font-size:10px}.review-filter{color:#7f8d75;align-items:center;gap:7px;margin:0 7px 15px;font-size:10px;display:flex}.students{padding:35px 40px;overflow:auto}.students h2{font-size:22px}.students>p{color:var(--muted);font-size:12px;line-height:1.8}.student-row{border-bottom:1px solid var(--line);align-items:center;gap:14px;padding:19px 0;display:flex}.student-row strong{font-size:13px}.student-row small{color:var(--muted);margin-top:5px;font-size:10px;display:block}.student-row .badge{margin-left:auto}.badge{color:#738960;background:#e9f1e4;border-radius:5px;padding:5px 9px;font-size:10px}.badge.amber{color:#9c874c;background:#f8f1df}.empty-panel{text-align:center;color:var(--muted);border:1px dashed var(--line);border-radius:10px;margin-top:25px;padding:70px 20px}.error-banner{color:#a35d47;background:#fff2ee;padding:12px 30px;font-size:12px;line-height:1.8}.sr-only{clip:rect(0,0,0,0);white-space:nowrap;border:0;width:1px;height:1px;margin:-1px;padding:0;position:absolute;overflow:hidden}@media (min-width:1500px){.hero{padding:120px 0}.chat-welcome{margin-top:70px}}@media (max-width:900px){.hero{gap:28px;padding:60px 0}h1{font-size:37px}.study-card{padding:20px}.hero-actions{flex-wrap:wrap;gap:15px}.auth-intro{padding:45px 35px}.auth-intro h1{font-size:37px}.workspace{grid-template-columns:225px minmax(0,1fr)}.chat-header{padding:22px}.chat-scroll{padding:20px}.composer-wrap{padding:10px 20px 15px}.chat-welcome h1{font-size:30px}.sample-answer strong{font-size:11px}.stars-diagram{gap:24px;margin-left:0}.concept-line{margin-left:0}}@media (max-width:640px){.topbar{height:82px;padding:0 20px}.topbar nav>a:first-child{display:none}.topbar .brand{font-size:21px}.landing main{padding:0 22px}.hero{grid-template-columns:1fr;gap:40px;padding:48px 0 50px}.hero-copy h1{font-size:36px}.hero-description{font-size:14px}.hero-actions{margin-top:26px}.study-card{padding:23px;transform:none}.sample-question{font-size:14px}.sample-answer{font-size:12px}.stars-diagram{margin-left:40px}.feature-grid{grid-template-columns:1fr;gap:12px}.feature-grid article{padding:22px}.feature-grid h3{margin-top:15px}.section-heading h2{font-size:24px}.early-note span{display:block}footer{flex-wrap:wrap;gap:16px;margin:0 22px}footer p{display:none}.auth-page{flex-direction:column;display:flex}.auth-intro{gap:20px;padding:24px}.auth-intro>div,.auth-intro>.text-link{display:none}.auth-form{padding:36px 27px}.workspace{flex-direction:column;height:auto;min-height:100dvh;display:flex;overflow:visible}.sidebar{border-right:0;border-bottom:1px solid var(--line);grid-template-columns:1fr auto;gap:15px;padding:15px 18px;display:grid}.sidebar .brand{font-size:18px}.sidebar .brand-icon{width:32px;height:32px}.sidebar .new-chat{width:auto;margin:0;padding:9px 12px;font-size:11px}.sidebar-label{grid-column:1/-1;margin:0}.thread-list{grid-column:1/-1;max-height:140px}.thread{padding:8px}.account{grid-column:1/-1;padding-top:9px}.teacher-nav{flex-direction:row;grid-column:1/-1;margin:0}.review-filter{grid-column:1/-1;margin:0}.chat-main{min-height:78dvh}.chat-header{padding:18px}.chat-header h2{max-width:62vw;font-size:14px}.chat-scroll{padding:20px 18px;overflow:visible}.chat-welcome{margin-top:16px}.chat-welcome h1{font-size:30px}.chat-welcome p{font-size:12px}.suggestions button{font-size:11px}.composer-wrap{background:#fdfefbf2;padding:15px;position:sticky;bottom:0}.composer-hint{font-size:9px}.students{padding:22px 18px}.student-row{flex-wrap:wrap;gap:9px}.student-row .button{padding:8px 11px;font-size:10px}.message{font-size:13px}.message.user{margin-left:8%}.status-pill{font-size:9px}.composer-top>span{font-size:8px}}@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}