@import"https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;500;600;700&display=swap";:root{color-scheme:light;--ground: #f6f7f9;--surface: #ffffff;--line: #e6e9ef;--line-soft: #eef1f5;--ink: #0f172a;--body: #475569;--muted: #94a3b8;--accent: #2563eb;--accent-hover: #1d4ed8;--accent-wash: #eef4ff;--done: #15803d;--done-wash: #ecfdf3;--warning: #92400e;--warning-wash: #fef3c7;--danger: #b91c1c;--danger-wash: #fee2e2;--radius: 10px;--radius-control: 8px;--font: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;font-family:var(--font);line-height:1.55;color:var(--ink);background:var(--ground)}*{box-sizing:border-box}html,body,#root{min-height:100%}body{margin:0;min-width:320px;background:var(--ground);color:var(--ink);-webkit-font-smoothing:antialiased}h1,h2,h3{margin:0;line-height:1.25;letter-spacing:-.01em;color:var(--ink)}p,ul{margin:0}a{color:inherit}button,input,textarea{font:inherit}button{transition:background-color .15s ease,border-color .15s ease,color .15s ease}button:focus-visible,input:focus-visible,textarea:focus-visible,a:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.skip-link{position:absolute;left:16px;top:-60px;z-index:30;padding:10px 14px;border-radius:var(--radius-control);background:var(--surface);border:1px solid var(--line)}.skip-link:focus{top:16px}.center-screen{min-height:100vh;display:grid;place-items:center;padding:24px;color:var(--body)}.page-shell{width:min(1120px,100%);margin:0 auto;min-height:100vh;padding:18px 20px 44px}.page-shell-narrow{width:min(760px,100%)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:var(--radius-control);padding:11px 16px;font-weight:600;font-size:14.5px;cursor:pointer;text-decoration:none;white-space:nowrap}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover{background:var(--accent-hover)}.btn-ghost{background:var(--surface);color:var(--body);border:1px solid 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2px}.lesson-summary{color:var(--muted);font-size:13.5px;margin:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.lesson-bar{height:5px;border-radius:3px;background:var(--line);margin-top:9px;max-width:240px;overflow:hidden}.lesson-bar>i{display:block;height:100%;border-radius:3px;background:var(--accent)}.lesson-actions{display:flex;align-items:center;gap:14px;justify-content:flex-end}.lesson-state{display:inline-flex;align-items:center;gap:6px;font-size:13px;font-weight:600;white-space:nowrap}.lesson-state-done{color:var(--done)}.lesson-state-locked{color:var(--muted)}.lesson-go{color:var(--accent);font-weight:600;font-size:14px;white-space:nowrap}.lesson-row-locked{cursor:default}.lesson-row-locked .lesson-idx{color:var(--muted)}.lesson-row-locked .lesson-title{color:var(--body)}.icon{width:15px;height:15px;flex:0 0 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p{color:var(--body)}.lesson-blocked-tag{font-size:12px;font-weight:700;letter-spacing:.04em;color:var(--muted);text-transform:uppercase}.tutor-panel{display:flex;flex-direction:column;flex:0 0 var(--tutor-width);width:var(--tutor-width);min-width:0;position:sticky;top:16px;align-self:start;height:calc(100vh - 32px);background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden}.tutor-header{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:14px 16px;border-bottom:1px solid var(--line-soft);flex:0 0 auto}.tutor-title{display:flex;align-items:center;gap:8px;font-weight:600;font-size:14px}.tutor-live{width:7px;height:7px;border-radius:50%;background:var(--done)}.tutor-newchat{border:0;background:none;color:var(--muted);font-size:13px;cursor:pointer;padding:4px 6px;border-radius:6px}.tutor-newchat:hover:not(:disabled){color:var(--body);background:var(--ground)}.tutor-newchat:disabled{opacity:.45;cursor:not-allowed}.gate-card{flex:0 0 auto;margin:14px 16px 2px;padding:13px 14px;background:var(--accent-wash);border-radius:9px}.gate-label{font-size:11.5px;font-weight:700;letter-spacing:.04em;color:var(--accent);margin-bottom:5px}.gate-card p{margin:0;font-size:13.5px;line-height:1.5;color:var(--ink)}.chat-list{flex:1;min-height:0;overflow:auto;padding:16px;display:grid;gap:14px;align-content:start;scroll-behavior:smooth}.chat-turn{display:grid;gap:10px}.bubble{max-width:88%;padding:10px 13px;border-radius:14px;font-size:14px;line-height:1.5;white-space:pre-wrap}.bubble-user{justify-self:end;background:var(--accent);color:#fff;border-bottom-right-radius:4px}.bubble-assistant{justify-self:start;background:var(--ground);color:var(--ink);border-bottom-left-radius:4px}.tutor-form{flex:0 0 auto;padding:12px 14px;border-top:1px solid 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reduce){*,*:before,*:after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}}.stat-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:12px;margin-bottom:28px}.stat-tile{display:flex;flex-direction:column;gap:2px;padding:14px 16px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius)}.stat-value{font-size:24px;font-weight:600;color:var(--ink)}.stat-label{font-size:13px;color:var(--muted)}.teacher-block{margin-bottom:32px}.teacher-block h2{font-size:16px;font-weight:600;margin-bottom:12px}.gates{display:flex;flex-direction:column;gap:10px}.gate-row{padding:14px 16px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius)}.gate-head{display:flex;justify-content:space-between;align-items:baseline;gap:12px;margin-bottom:8px}.gate-title{font-weight:500;color:var(--ink)}.gate-rate{font-size:13px;color:var(--body);white-space:nowrap}.gate-bar{display:block;max-width:none;margin-top:0}.gate-meta{display:flex;flex-wrap:wrap;gap:4px 16px;margin-top:8px;font-size:13px;color:var(--muted)}.gate-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}.gate-summary{margin-top:12px;padding:12px;background:var(--accent-wash);border-radius:var(--radius-control);font-size:14px;color:var(--body);white-space:pre-wrap}.failures{list-style:none;padding:0;margin-top:12px;display:flex;flex-direction:column;gap:10px}.failures li{display:flex;flex-direction:column;gap:2px;padding:10px 12px;background:var(--ground);border-radius:var(--radius-control)}.failure-who{font-size:12px;color:var(--muted)}.failure-answer{font-size:14px;color:var(--ink);white-space:pre-wrap}.failure-note{font-size:13px;color:var(--warning)}.students-wrap{overflow-x:auto}.students{width:100%;border-collapse:collapse;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden}.students th,.students td{padding:10px 14px;text-align:left;font-size:14px;border-bottom:1px solid var(--line-soft)}.students th{font-size:12px;font-weight:500;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}.students tr:last-child td{border-bottom:none}.student-name{display:block;color:var(--ink)}.student-email{display:block;font-size:12px;color:var(--muted)}.student-alias-sub{display:block;font-size:11.5px;font-weight:500;color:var(--body);margin-top:2px}.student-email-sub{display:block;font-size:11px;color:var(--muted);margin-top:1px}.student-duration-badges{display:flex;align-items:center;flex-wrap:wrap;gap:6px}.lesson-dur-badge{display:inline-flex;align-items:center;padding:2px 7px;border-radius:6px;font-size:12px;font-weight:600;background:var(--ground);border:1px solid var(--line);color:var(--ink);white-space:nowrap}.lesson-dur-total{font-size:12px;font-weight:600;color:var(--muted);margin-left:2px;white-space:nowrap}.teacher-toolbar{margin-bottom:24px;padding:12px 16px;background:var(--surface);border:1px solid 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.failure-answer{font-size:15px;line-height:1.5;font-weight:500}.presentation-mode .failure-who{font-size:13px;font-weight:600;color:var(--accent)}.class-context-info h1{font-size:20px;font-weight:700;color:var(--ink);margin:0}.class-title-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.class-badge{font-size:11px;font-weight:700;padding:3px 8px;border-radius:6px;background:var(--ink);color:#fff;letter-spacing:.05em;text-transform:uppercase}.live-pill{font-size:12px;font-weight:600;padding:3px 10px;border-radius:12px;background:#10b9811a;color:#059669}.presentation-pill{background:#2563eb1f;color:#2563eb}.class-context-sub{font-size:13px;color:var(--muted);margin-top:4px;display:flex;gap:8px;align-items:center}.presentation-alert-bar{display:flex;align-items:center;gap:10px;padding:10px 16px;margin-bottom:20px;background:#eff6ff;border:1px solid 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ease}.teacher-tab-btn:hover{color:var(--ink)}.teacher-tab-btn.active{color:var(--accent);border-bottom-color:var(--accent)}.teacher-tab-badge{font-size:11px;padding:2px 7px;border-radius:10px;background:var(--line);color:var(--body)}.teacher-tab-btn.active .teacher-tab-badge{background:var(--accent-wash);color:var(--accent)}.lesson-filter-pills{display:flex;gap:6px;flex-wrap:wrap;align-items:center}.filter-pill{padding:5px 12px;border-radius:20px;font-size:12px;font-weight:500;background:var(--surface);border:1px solid var(--line);color:var(--body);cursor:pointer;transition:all .15s ease}.filter-pill:hover{border-color:var(--muted);color:var(--ink)}.filter-pill.active{background:var(--ink);border-color:var(--ink);color:#fff}.student-search-box{width:260px}.student-search-input{width:100%;font-size:13px;padding:7px 12px}.group-title-with-btn{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.btn-artifact-link{background:var(--accent-wash);color:var(--accent);border:1px solid 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4px;font-size:17px;font-weight:600;color:var(--ink)}.modal-subtitle{margin:0;font-size:13px;color:var(--muted)}.btn-modal-close{background:transparent;border:none;font-size:20px;line-height:1;color:var(--muted);cursor:pointer;padding:4px 8px;border-radius:var(--radius-control);transition:all .12s ease}.btn-modal-close:hover{background:var(--line);color:var(--ink)}.artifact-task-tabs{display:flex;gap:8px;padding:12px 20px;border-bottom:1px solid var(--line-soft);background:var(--surface);flex-wrap:wrap}.artifact-image-container{padding:20px;overflow-y:auto;display:flex;flex-direction:column;gap:16px;align-items:center;background:#0f172a05}.artifact-img-wrap{width:100%;display:flex;flex-direction:column;align-items:center;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:12px}.artifact-img{max-width:100%;max-height:65vh;object-fit:contain;border-radius:6px;box-shadow:0 4px 6px -1px 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12px;border-radius:8px}.chat-gate-turns{display:flex;flex-direction:column;gap:14px}.chat-log-exchange{display:flex;flex-direction:column;gap:10px}.chat-log-user-wrap{display:flex;flex-direction:column;align-items:flex-end;gap:4px}.chat-log-ai-wrap{display:flex;flex-direction:column;align-items:flex-start;gap:4px}.chat-log-ai-header{display:flex;align-items:center;gap:8px}.chat-log-meta{font-size:11.5px;font-weight:500;color:var(--muted)}.chat-log-bubble{max-width:85%;font-size:13.5px}.turn-decision-badge{font-size:11px;font-weight:600;padding:2px 7px;border-radius:6px}.turn-badge-pass{background:var(--done-wash);color:var(--done)}.turn-badge-fail{background:var(--danger-wash);color:var(--danger)}.turn-badge-clarify{background:var(--warning-wash);color:var(--warning)}.turn-badge-extend{background:var(--accent-wash);color:var(--accent)}.chat-log-eval-note{font-size:12px;color:var(--body);font-style:italic;padding-left:4px}@keyframes modal-fade{0%{opacity:0}to{opacity:1}}@keyframes 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2px}.landing-title{font-size:clamp(1.45rem,2.5vw,2.15rem);font-weight:700;line-height:1.32;letter-spacing:-.02em;color:var(--ink);max-width:34ch;text-wrap:balance}.landing-title-main{display:block;color:#1e3a8a}.landing-title-sub{display:block;color:var(--ink)}.landing-grade-tabs{display:inline-flex;align-items:center;flex-wrap:wrap;justify-content:center;gap:8px;padding:6px;background:#fffffff0;border:1px solid rgba(37,99,235,.16);border-radius:13px;box-shadow:0 10px 28px #0f172a12}.landing-grade-tab{display:inline-flex;align-items:center;gap:8px;padding:9px 20px;border-radius:9px;font-size:14.5px;font-weight:600;color:var(--body);text-decoration:none;white-space:nowrap;background:transparent;transition:background-color .15s ease,color .15s ease,transform .15s ease}.landing-grade-tab:hover{color:var(--ink);background:var(--ground)}.landing-grade-tab-featured{background:var(--accent);color:#fff;box-shadow:0 2px 8px #2563eb47}.landing-grade-tab-featured:hover{background:var(--accent-hover);color:#fff}.landing-grade-cta{font-size:12px;font-weight:600;padding:2px 8px;border-radius:6px;background:#fff3;color:#fff;white-space:nowrap}.landing-artwork-stage{width:min(1000px,100%);margin:0 auto;overflow:hidden;pointer-events:none;-webkit-user-select:none;user-select:none}.landing-artwork{display:block;width:100%;height:auto;margin-top:-15%;margin-bottom:-11.5%;-webkit-mask-image:radial-gradient(ellipse 49% 47% at 50% 51%,#000 78%,transparent 100%);mask-image:radial-gradient(ellipse 49% 47% at 50% 51%,#000 78%,transparent 100%)}.grade-empty-box{margin-top:14px;padding:28px 24px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;color:var(--body);font-size:14.5px}.auth-logo-link{display:block;margin:0 auto 18px;width:46px;height:46px}.auth-logo-link 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