:root{--education-teal:#08786f;--education-ink:#17212b;--education-muted:#596773;--education-border:#dce5e5;--education-surface:#fff;--education-canvas:#fbfcfd;--education-cream:#f7f1e9;color:var(--education-ink);background:var(--education-canvas);font-synthesis:none;font-family:PingFang SC,Microsoft YaHei,system-ui,sans-serif;line-height:1.6}*{box-sizing:border-box}body{min-width:320px;margin:0}button,input,textarea,select{font:inherit}button{cursor:pointer;border:1px solid var(--education-border);color:var(--education-ink);background:#fff;border-radius:8px;min-height:44px;padding:10px 18px;transition:background .15s,transform .15s}button:hover:not(:disabled){background:#edf5f3}button:active:not(:disabled){transform:translateY(1px)}button:disabled{opacity:.55;cursor:not-allowed}button.primary{background:var(--education-teal);border-color:var(--education-teal);color:#fff}button.primary:hover:not(:disabled){background:#065e57}:focus-visible{outline-offset:3px;outline:2px solid #4dbfb4}input,select,textarea{width:100%;color:inherit;background:#fff;border:1px solid #aebcbe;border-radius:8px;padding:11px 12px;display:block}textarea{resize:vertical}label{font-weight:600;display:block}label input,label textarea,label select{margin-top:8px;font-weight:400}form{gap:20px;display:grid}h1,h2,h3,p{margin-top:0}h1{margin-bottom:12px;font-size:clamp(25px,3vw,34px);line-height:1.45}h2{font-size:21px;line-height:1.5}h3{font-size:18px}a{color:var(--education-teal)}.muted{color:var(--education-muted)}.small,small{font-size:13px}.brand{color:var(--education-ink);flex-direction:column;text-decoration:none;display:flex}.brand>span{letter-spacing:.13em;font-size:25px;font-weight:700}.brand>small{color:var(--education-muted);letter-spacing:.06em;margin-top:4px;font-size:11px}.eyebrow{color:var(--education-teal);letter-spacing:.12em;margin-bottom:12px;font-size:12px}.notice{color:#744419;background:#fff3e6;border:1px solid #e9cba6;border-radius:8px;padding:14px 18px}.actions{flex-wrap:wrap;align-items:center;gap:12px;display:flex}.panel{border:1px solid var(--education-border);background:#fff;border-radius:12px;margin-bottom:24px;padding:28px}.brief{white-space:pre-wrap;overflow-wrap:anywhere}.loading{color:var(--education-muted);padding:60px}.access{background:radial-gradient(at 18% 10%,#f6e4e8 0,#0000 40%),#edf6f3;place-items:center;min-height:100dvh;padding:24px;display:grid}.access-card{border:1px solid var(--education-border);background:#fff;border-radius:16px;width:min(100%,480px);padding:40px}.access-card .brand{margin-bottom:40px}.access-card form{margin-top:28px}.access-card .small{margin-top:20px;margin-bottom:0}.teacher-layout{grid-template-columns:240px minmax(0,1fr);min-height:100dvh;display:grid}.sidebar{border-right:1px solid var(--education-border);background:#fff;flex-direction:column;gap:28px;height:100dvh;padding:28px 18px;display:flex;position:sticky;top:0}.sidebar nav{flex-direction:column;flex:1;gap:10px;display:flex;overflow:auto}.sidebar nav button{text-align:left;border-color:#0000;padding:16px}.sidebar nav strong{overflow-wrap:anywhere;display:block}.sidebar nav small{color:var(--education-muted)}.sidebar nav .selected{border-color:#cce4df;border-left:4px solid var(--education-teal);background:#eef7f5}.workspace{width:100%;max-width:1500px;padding:0 40px 40px}.toolbar{border-bottom:1px solid var(--education-border);height:80px;color:var(--education-muted);justify-content:space-between;align-items:center;margin-bottom:32px;display:flex}.page-heading{justify-content:space-between;align-items:center;gap:24px;margin-bottom:28px;display:flex}.status{background:#edf1f3;border-radius:6px;padding:3px 10px;font-size:12px;display:inline-block}.status.open{color:#156344;background:#e7f5ee}.overview{grid-template-columns:minmax(0,1.6fr) minmax(260px,1fr);gap:24px;display:grid}.metrics{gap:50px;margin:36px 0;display:flex}.metrics strong{font-variant-numeric:tabular-nums;font-size:36px;font-weight:600;display:block}.metrics span{color:var(--education-muted);font-size:13px}.invite img{margin:12px auto;display:block}.invite input{margin-bottom:12px;font-size:12px}.gallery{grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:24px;display:grid}.gallery figure{margin:0}.gallery img{aspect-ratio:1;object-fit:contain;background:#f6f7f5;border-radius:8px;width:100%}.gallery figcaption{overflow-wrap:anywhere;margin-top:8px;font-size:14px}.empty{text-align:center;color:var(--education-muted);padding:60px 24px}.create{max-width:760px}.watercolor-backdrop{background:var(--watercolor-image) center / cover fixed no-repeat;min-height:100dvh}.student-shell{max-width:800px;margin:auto;padding:28px 24px 60px}.student-header{justify-content:space-between;align-items:center;gap:20px;display:flex}.course-welcome{padding:56px 6px 28px}.student-shell .panel{background:#fffffff5}.student-shell .consent{align-items:flex-start;gap:12px;margin:26px 0 12px;font-size:14px;font-weight:400;display:flex}.consent input{width:20px;height:20px;accent-color:var(--education-teal);flex-shrink:0;margin-top:3px}.student-artwork{object-fit:contain;background:#f7f7f4;border-radius:8px;width:100%;max-height:430px;margin-bottom:20px;display:block}.student-footer{text-align:center;color:#544d49;margin-top:40px;font-size:13px}.finish{border-style:dashed}.assistant-dialog{border:1px solid var(--education-border);width:min(640px,100% - 32px);max-height:calc(100dvh - 40px);color:var(--education-ink);background:#fbfcfb;border-radius:16px;padding:0}.assistant-dialog[open]{flex-direction:column;display:flex}.assistant-dialog::backdrop{background:#17212b73}.assistant-dialog>header{border-bottom:1px solid var(--education-border);background:#fff;justify-content:space-between;align-items:center;gap:16px;padding:20px 24px;display:flex}.assistant-dialog h2,.assistant-dialog header p{margin-bottom:0}.chat-body{overscroll-behavior:contain;min-height:180px;padding:24px;overflow-y:auto}.chat-intro{color:var(--education-muted);padding:12px 0}.turn{margin-bottom:24px}.turn p{white-space:pre-wrap;overflow-wrap:anywhere;border-radius:12px;padding:16px;font-size:15px}.turn p>span{color:var(--education-muted);margin-bottom:7px;font-size:11px;display:block}.student-message{background:#e7f2ee;margin-left:40px}.assistant-message{border:1px solid var(--education-border);background:#fff;margin-right:16px}.thinking{color:var(--education-teal)}.composer{border-top:1px solid var(--education-border);background:#fff;gap:12px;padding:20px 24px}.composer-options{grid-template-columns:1fr 1fr;gap:12px;font-size:12px;display:grid}.composer label select{margin-top:4px;padding:7px 10px}.composer .actions{justify-content:space-between}.attachment{align-items:center;gap:12px;font-size:12px;display:flex}.attachment img{object-fit:contain;width:44px;height:44px}.attachment span{overflow-wrap:anywhere}.sr-only{clip-path:inset(50%);width:1px;height:1px;position:absolute;overflow:hidden}@media (width<=1000px){.overview{grid-template-columns:1fr}.workspace{padding:0 24px 28px}.metrics{gap:36px}}@media (width<=700px){.teacher-layout{display:block}.sidebar{border-right:0;gap:16px;height:auto;padding:20px;position:static}.sidebar nav{flex-direction:row;max-height:150px}.sidebar nav button{flex-shrink:0;max-width:220px}.workspace{padding:0 16px 24px}.toolbar{height:60px;margin-bottom:24px}.page-heading{flex-direction:column;align-items:flex-start}.panel{padding:22px}.student-shell{padding:24px 16px 40px}.course-welcome{padding-top:40px}.watercolor-backdrop{background-image:var(--watercolor-image-portrait);background-attachment:scroll}.assistant-dialog{border-radius:18px 18px 0 0;width:100%;max-height:94dvh;margin:auto auto 0}.assistant-dialog>header,.composer,.chat-body{padding:16px}.assistant-dialog h2{font-size:19px}.composer{padding-bottom:max(16px, env(safe-area-inset-bottom))}.access-card{padding:28px}}@media (prefers-reduced-motion:reduce){*,:before,:after{scroll-behavior:auto!important;transition:none!important}}