:root{--bg:#f6f2e9;--paper:#fffdf8;--ink:#221f1a;--muted:#74695c;--line:#e3d7c6;--red:#b5483a;--blue:#315f85;--gold:#b88728;--green:#47745a;--shadow:0 12px 30px rgba(67,45,23,.09)}
*{box-sizing:border-box} body{margin:0;background:linear-gradient(180deg,#fbf7ef 0,#f0e7d9 100%);color:var(--ink);font:16px/1.65 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Noto Sans CJK SC",Arial,sans-serif} a{color:var(--blue);text-decoration:none} a:hover{text-decoration:underline}.shell{max-width:1180px;margin:0 auto;padding:0 22px}.topbar{position:sticky;top:0;z-index:20;background:rgba(255,253,248,.94);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}.topbar .shell{display:flex;align-items:center;justify-content:space-between;gap:20px;padding-top:12px;padding-bottom:12px}.brand{display:flex;align-items:center;gap:10px;font-weight:800}.brand-mark{width:34px;height:34px;border-radius:10px;background:linear-gradient(135deg,var(--red),var(--gold));display:grid;place-items:center;color:#fff}.nav{display:flex;gap:10px;flex-wrap:wrap}.nav a{padding:7px 11px;border:1px solid var(--line);border-radius:999px;background:#fff;color:#4b4035;font-size:14px}.hero{padding:54px 0 30px}.hero-grid{display:grid;grid-template-columns:1.25fr .75fr;gap:28px;align-items:stretch}.hero-card,.panel,.report-card,.qr-card{background:var(--paper);border:1px solid var(--line);border-radius:22px;box-shadow:var(--shadow)}.hero-card{padding:34px}.eyebrow{color:var(--red);font-weight:800;letter-spacing:.04em;font-size:13px}.hero h1{font-size:40px;line-height:1.12;margin:10px 0 14px}.hero p{color:var(--muted);margin:0}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:24px}.btn{display:inline-flex;align-items:center;justify-content:center;border-radius:12px;padding:10px 14px;font-weight:700;border:1px solid var(--line);background:#fff;color:var(--ink)}.btn.primary{background:var(--red);color:#fff;border-color:var(--red)}.panel{padding:22px}.panel h2,.section h2{margin:0 0 12px}.pill-list{display:flex;gap:8px;flex-wrap:wrap}.pill{border:1px solid var(--line);border-radius:999px;background:#fff;padding:5px 9px;font-size:13px;color:#5b4e41}.section{padding:28px 0}.section-head{display:flex;align-items:end;justify-content:space-between;gap:16px;margin-bottom:14px}.section-head p{margin:0;color:var(--muted)}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.report-card{padding:22px}.report-card h3{margin:0 0 8px;font-size:22px}.meta{color:var(--muted);font-size:14px}.status{display:inline-block;border-radius:999px;padding:4px 9px;background:#fff4d8;border:1px solid #ead09a;color:#76551a;font-size:12px;font-weight:700}.card-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:16px}.boundary{margin:14px 0 0;padding-left:1.2em;color:#5d5146}.qr-layout{display:grid;grid-template-columns:330px 1fr;gap:18px}.qr-card{padding:20px}.qr-img{width:100%;aspect-ratio:1;background:#fff;border:1px solid var(--line);border-radius:16px;display:grid;place-items:center;overflow:hidden}.qr-img img{max-width:92%;height:auto}.teacher-steps{background:#fff;border:1px dashed var(--line);border-radius:16px;padding:16px}.teacher-steps li{margin:8px 0}.footer{border-top:1px solid var(--line);padding:24px 0;color:var(--muted);font-size:13px}.warn{background:#fff8e8;border:1px solid #ead19b;border-left:5px solid var(--gold);border-radius:14px;padding:12px 14px;margin:12px 0}.empty{padding:18px;border:1px dashed var(--line);border-radius:16px;color:var(--muted);background:#fff}@media(max-width:820px){.hero-grid,.grid,.qr-layout{grid-template-columns:1fr}.hero h1{font-size:32px}.topbar .shell{align-items:flex-start;flex-direction:column}}

.hero.compact{padding:38px 0 18px}.hero.compact .hero-card{padding:28px}.hero.compact h1{font-size:34px}.report-card h3,.qr-card h3{font-weight:700}.status{background:#eef7f0;border-color:#c7e3cf;color:#2f6b43}.boundary{font-size:14px}.teacher-steps strong{font-size:18px}


/* Workbench */
.term-layout{display:grid;grid-template-columns:1fr 360px;gap:22px;align-items:start}.lesson-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px}.lesson-tile{background:var(--paper);border:1px solid var(--line);border-radius:18px;padding:18px;box-shadow:var(--shadow)}.lesson-tile h3{margin:4px 0 8px}.workbench-shell{max-width:1440px;margin:0 auto;padding:22px}.lesson-workbench{display:grid;grid-template-columns:minmax(0,1fr) 390px;gap:18px}.lesson-frame{height:calc(100vh - 150px);min-height:680px;background:#fff;border:1px solid var(--line);border-radius:20px;overflow:hidden;box-shadow:var(--shadow)}.lesson-frame iframe{width:100%;height:100%;border:0}.chat-panel{position:sticky;top:78px;background:var(--paper);border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow);padding:16px;max-height:calc(100vh - 96px);display:flex;flex-direction:column;gap:12px}.chat-panel h2{margin:0;font-size:20px}.thread-label{font-size:12px;color:var(--muted);word-break:break-all}.chat-messages{border:1px solid var(--line);border-radius:14px;background:#fffaf2;padding:10px;min-height:260px;overflow:auto;flex:1}.msg{border-bottom:1px solid #eee0ce;padding:10px 0}.msg:last-child{border-bottom:0}.msg-meta{font-size:12px;color:var(--muted);margin-bottom:4px}.msg.user .msg-text{font-weight:650}.msg-text{white-space:normal}.chat-input{width:100%;min-height:110px;border:1px solid var(--line);border-radius:14px;padding:10px;background:#fff;font:inherit;resize:vertical}.chat-actions{display:flex;gap:8px;flex-wrap:wrap}.risk-note{font-size:13px;color:var(--muted);background:#f7efe4;border:1px solid var(--line);border-radius:12px;padding:10px}@media(max-width:980px){.term-layout,.lesson-workbench{grid-template-columns:1fr}.chat-panel{position:static;max-height:none}.lesson-frame{height:72vh}}