:root{--ink:#18251f;--muted:#66736c;--paper:#f5f4ef;--card:#fff;--line:#dfe4df;--green:#176a45;--green2:#2f8c61;--mint:#dceee4;--amber:#f0b83d;--red:#d85b4a;--shadow:0 18px 50px rgba(22,50,36,.10)}
*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--paper)}button,input,select,textarea{font:inherit}.hidden{display:none!important}.eyebrow{margin:0 0 8px;color:var(--green2);font-size:12px;font-weight:800;letter-spacing:.18em}.login-page{min-height:100vh;display:grid;grid-template-columns:1.1fr .9fr}.brand-panel{position:relative;overflow:hidden;background:#123e2b;color:white;padding:7vw;display:flex;flex-direction:column;justify-content:space-between}.brand-panel:after{content:"";position:absolute;width:520px;height:520px;border:1px solid rgba(255,255,255,.12);border-radius:50%;right:-180px;top:-160px;box-shadow:0 0 0 70px rgba(255,255,255,.025),0 0 0 140px rgba(255,255,255,.02)}.brand-mark,.logo span,.mobile-logo span{display:grid;place-items:center;width:46px;height:46px;background:#f1c65b;color:#173c2c;border-radius:14px;font-family:serif;font-size:25px;font-weight:900}.brand-panel h1{font-family:serif;font-size:clamp(42px,5vw,74px);line-height:1.1;margin:25px 0}.brand-copy{max-width:560px;color:#cadbd2;font-size:17px;line-height:1.8}.signal-art{height:120px;display:flex;align-items:flex-end;gap:14px}.signal-art i{width:16px;border-radius:20px;background:#67b487;animation:pulse 2s ease-in-out infinite}.signal-art i:nth-child(1){height:32px}.signal-art i:nth-child(2){height:60px}.signal-art i:nth-child(3){height:92px}.signal-art i:nth-child(4){height:68px}.signal-art i:nth-child(5){height:105px}.signal-art i:nth-child(6){height:46px}@keyframes pulse{50%{opacity:.4;transform:scaleY(.72)}}.login-card{padding:8vh 10vw;display:flex;flex-direction:column;justify-content:center;background:#fbfaf7}.login-card h2{font-size:34px;margin:0 0 26px}.mobile-logo{display:none}.tabs{display:flex;border-bottom:1px solid var(--line);margin-bottom:24px}.tab{border:0;background:none;padding:12px 4px;margin-right:24px;color:var(--muted);cursor:pointer}.tab.active{color:var(--green);font-weight:800;border-bottom:2px solid var(--green)}.login-form{display:grid;gap:18px}.login-form label,.field{display:grid;gap:8px;font-size:13px;font-weight:700}.hint{float:right;color:var(--muted);font-weight:400}input,select,textarea{border:1px solid #cfd6d1;background:white;border-radius:10px;padding:12px 14px;color:var(--ink);outline:none}input:focus,select:focus,textarea:focus{border-color:var(--green2);box-shadow:0 0 0 3px rgba(47,140,97,.12)}button{cursor:pointer}.primary{border:0;border-radius:10px;background:var(--green);color:white;padding:12px 18px;font-weight:800}.primary:hover{background:#105837}.wide{width:100%}.divider{text-align:center;border-top:1px solid var(--line);margin:26px 0 14px;height:10px}.divider span{position:relative;top:-10px;background:#fbfaf7;padding:0 12px;color:var(--muted);font-size:12px}.oauth-row{display:flex;justify-content:center;gap:12px}.oauth{width:42px;height:42px;border-radius:50%;border:1px solid var(--line);background:#e6f4e9;color:#188444;font-weight:900}.oauth.qq{background:#e8f1f8;color:#3186c1}.demo-accounts{margin-top:28px;padding:14px;border:1px dashed #bdc9c1;border-radius:12px;display:flex;gap:8px;flex-wrap:wrap;font-size:12px}.demo-accounts strong,.demo-accounts span{width:100%;color:var(--muted)}.demo-accounts button{border:0;background:var(--mint);color:var(--green);border-radius:20px;padding:7px 10px}.app{min-height:100vh;display:grid;grid-template-columns:250px 1fr}.sidebar{position:sticky;top:0;height:100vh;background:#123e2b;color:white;padding:24px 18px;display:flex;flex-direction:column}.logo{display:flex;align-items:center;gap:12px;font-size:20px;padding:0 8px 22px}.logo span{width:38px;height:38px;font-size:21px;border-radius:11px}.course-chip{background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.1);border-radius:13px;padding:14px;display:grid;gap:5px;margin-bottom:24px}.course-chip small,.course-chip span{color:#aac3b6;font-size:11px}.sidebar nav{display:grid;gap:5px}.nav-btn{border:0;background:transparent;color:#c8d9d0;border-radius:9px;text-align:left;padding:12px 14px}.nav-btn.active,.nav-btn:hover{background:#f1c65b;color:#173c2c;font-weight:800}.sidebar-bottom{margin-top:auto}.user-badge{display:flex;gap:10px;align-items:center;border-top:1px solid rgba(255,255,255,.12);padding:16px 4px}.avatar{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;background:#dceee4;color:#176a45;font-weight:900}.user-badge small{display:block;color:#aac3b6}.ghost{background:transparent;border:1px solid rgba(255,255,255,.2);color:#dce8e1;border-radius:9px;padding:9px}.workspace{min-width:0}.topbar{height:96px;background:rgba(255,255,255,.8);backdrop-filter:blur(12px);border-bottom:1px solid var(--line);padding:20px 36px;display:flex;justify-content:space-between;align-items:center;position:sticky;top:0;z-index:4}.topbar h2{margin:0;font-size:24px}.live{background:#e8f4ed;color:var(--green);padding:8px 12px;border-radius:20px;font-size:12px;font-weight:800}.live i{display:inline-block;width:7px;height:7px;border-radius:50%;background:#3aa66e;margin-right:6px;box-shadow:0 0 0 4px rgba(58,166,110,.15)}.content{padding:28px 36px 60px;max-width:1400px}.grid{display:grid;gap:18px}.grid.two{grid-template-columns:repeat(2,minmax(0,1fr))}.grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}.grid.four{grid-template-columns:repeat(4,minmax(0,1fr))}.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:22px;box-shadow:0 5px 18px rgba(20,44,32,.035)}.card h3{margin:0 0 18px;font-size:17px}.metric{position:relative;overflow:hidden}.metric b{font-size:31px}.metric span{display:block;color:var(--muted);font-size:12px;margin-top:7px}.metric:after{content:"";position:absolute;width:70px;height:70px;border-radius:50%;background:var(--mint);right:-18px;top:-20px}.hero-feedback{background:linear-gradient(135deg,#174f37,#0f3727);color:white;border:0}.hero-feedback h3{font-size:25px;margin-bottom:5px}.hero-feedback p{color:#bcd3c7;margin-top:0}.emoji-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:10px;margin-top:22px}.emoji-btn{border:1px solid rgba(255,255,255,.14);background:rgba(255,255,255,.08);border-radius:14px;color:white;padding:14px 6px;transition:.18s}.emoji-btn:hover{transform:translateY(-4px);background:#f2c55c;color:#173c2c}.emoji-btn strong{display:block;font-size:30px}.emoji-btn span{font-size:11px}.bars{height:230px;display:flex;align-items:flex-end;justify-content:space-around;gap:10px;border-bottom:1px solid var(--line);padding-top:25px}.bar{flex:1;max-width:54px;min-height:4px;border-radius:8px 8px 0 0;background:linear-gradient(#4ca577,#176a45);position:relative}.bar b{position:absolute;top:-24px;width:100%;text-align:center;font-size:12px}.bar span{position:absolute;bottom:-26px;width:100%;text-align:center;font-size:12px;color:var(--muted)}.pie-wrap{display:flex;align-items:center;justify-content:center;min-height:230px}.pie{width:175px;height:175px;border-radius:50%;position:relative}.pie:after{content:"";position:absolute;inset:33px;background:white;border-radius:50%}.toolbar,.form-row{display:flex;gap:10px;align-items:end;flex-wrap:wrap}.toolbar input,.toolbar select{min-width:160px}.secondary{border:1px solid var(--line);background:white;color:var(--ink);border-radius:9px;padding:10px 14px;font-weight:700}.danger{border:0;background:#fff0ee;color:#af3f32;border-radius:8px;padding:7px 10px}.table-wrap{overflow:auto;margin-top:16px}table{width:100%;border-collapse:collapse;white-space:nowrap}th,td{text-align:left;padding:12px;border-bottom:1px solid var(--line);font-size:13px}th{color:var(--muted);font-size:11px;text-transform:uppercase}.discussion{height:500px;display:grid;grid-template-rows:1fr auto}.messages{overflow:auto;display:flex;flex-direction:column;gap:12px;padding-right:7px}.message{display:grid;grid-template-columns:36px 1fr;gap:10px}.message-body{background:#f1f4f1;border-radius:4px 13px 13px 13px;padding:10px 12px;max-width:680px}.message-meta{font-size:11px;color:var(--muted);margin-bottom:5px}.message-body img{max-width:260px;border-radius:9px;display:block}.composer{border-top:1px solid var(--line);padding-top:14px;display:flex;gap:9px}.composer input[type=text]{flex:1}.file-btn{border:1px solid var(--line);padding:10px 12px;border-radius:9px;background:white}.quiz{border-left:4px solid var(--amber)}.options{display:grid;gap:8px;margin:14px 0}.option{border:1px solid var(--line);border-radius:9px;padding:10px;background:white;text-align:left}.option:hover{border-color:var(--green2);background:#f0f8f3}.option.selected{background:var(--mint);border-color:var(--green)}.result-badge{display:inline-block;background:#edf5ef;color:var(--green);padding:6px 10px;border-radius:20px;font-size:12px;font-weight:800}.modal-form{display:grid;gap:12px}.modal-form textarea{min-height:75px}.section-head{display:flex;justify-content:space-between;align-items:center;margin:4px 0 14px}.section-head h3{margin:0}.empty{text-align:center;color:var(--muted);padding:35px}.toast{position:fixed;right:25px;bottom:25px;background:#172b21;color:white;padding:12px 18px;border-radius:10px;box-shadow:var(--shadow);opacity:0;transform:translateY(10px);transition:.25s;z-index:20}.toast.show{opacity:1;transform:none}.mobile-header{display:none}
@media(max-width:900px){.login-page{grid-template-columns:1fr}.brand-panel{display:none}.login-card{padding:8vh 8vw;min-height:100vh}.mobile-logo{display:flex;align-items:center;gap:10px;margin-bottom:70px;font-size:20px}.app{display:block}.sidebar{position:fixed;left:-270px;z-index:10;width:250px;transition:.2s}.sidebar.open{left:0}.mobile-header{height:58px;display:flex;align-items:center;justify-content:space-between;padding:0 18px;background:#123e2b;color:white;position:sticky;top:0;z-index:5}.mobile-header button{border:0;background:none;color:white;font-size:22px}.topbar{position:static;height:auto;padding:20px}.content{padding:20px}.grid.two,.grid.three,.grid.four{grid-template-columns:1fr}.emoji-grid{grid-template-columns:repeat(3,1fr)}}
@media(max-width:520px){.login-card h2{font-size:28px}.demo-accounts{display:grid}.emoji-btn strong{font-size:27px}.toolbar>*{width:100%}.composer{flex-wrap:wrap}.composer input[type=text]{min-width:100%}}
.class-status{margin-top:18px}
.class-status .section-head{align-items:flex-start}
.class-status .section-head h3{margin:0}
.status-summary{color:var(--muted);font-size:13px;margin:0 0 18px}
.status-overview{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-bottom:16px}
.status-overview>div{background:#f3f8f4;border:1px solid #e2ede5;border-radius:12px;padding:14px}
.status-overview small,.status-overview b{display:block}
.status-overview small{color:var(--muted);font-size:12px;margin-bottom:8px}
.status-overview b{font-size:17px}
.status-counts{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:10px}
.status-count{border:1px solid var(--line);border-radius:12px;padding:12px 10px;display:grid;gap:6px}
.status-count span,.status-count small{font-size:12px}
.status-count b{font-size:22px;color:var(--green)}
.status-count small{color:var(--muted)}
.privacy-note{color:var(--muted);font-size:12px;margin:16px 0 0}
@media(max-width:900px){.status-counts{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:520px){.status-overview{grid-template-columns:1fr}.status-counts{grid-template-columns:repeat(2,minmax(0,1fr))}.class-status .section-head{gap:10px}}
.learning-plans{margin-top:18px}
.learning-plans h3{margin-bottom:8px}
.learning-plans textarea{min-height:100px;resize:vertical}
.plan-actions{display:flex;align-items:center;justify-content:space-between;gap:12px}
.plan-actions small{font-size:12px;color:var(--muted)}
.plan-history{margin-top:26px;border-top:1px solid var(--line);padding-top:18px}
.plan-history h4{margin:0 0 12px}
.plan-entry{border:1px solid var(--line);border-radius:11px;padding:13px 15px;margin-top:10px;background:#fafcf9}
.plan-entry time{font-size:11px;color:var(--muted)}
.plan-entry p{white-space:pre-wrap;margin:8px 0 0;line-height:1.6}