:root { --bg:#f7f9fc; --surface:#fff; --soft:#f1f5f9; --text:#172033; --muted:#64748b; --primary:#2563eb; --primary-soft:#dbeafe; --success:#15803d; --success-soft:#dcfce7; --border:#e2e8f0; --shadow:0 12px 28px rgba(15,23,42,.06); }
* { box-sizing:border-box; } body { margin:0; background:var(--bg); color:var(--text); font:14px/1.55 "PingFang SC","Microsoft YaHei","Segoe UI",sans-serif; } a { color:inherit; }.app-shell{display:flex;min-height:100vh}.sidebar{position:fixed;z-index:2;display:flex;flex-direction:column;width:236px;height:100vh;padding:22px 14px;background:#fff;border-right:1px solid var(--border)}.sidebar-brand{display:flex;align-items:center;gap:10px;padding:0 10px 26px;text-decoration:none;font-size:19px;font-weight:800}.sidebar-brand small,.sidebar-footer small{display:block;color:var(--muted);font-size:11px;font-weight:500}.brand-mark{display:grid;place-items:center;width:35px;height:35px;border-radius:10px;background:var(--primary);color:#fff;font-weight:800}.side-nav{display:grid;gap:5px}.side-nav a,.side-nav-disabled{display:flex;align-items:center;gap:10px;padding:11px 12px;border-radius:9px;color:#64748b;text-decoration:none;font-weight:650}.side-nav a.active{background:var(--primary-soft);color:#1d4ed8}.side-nav-disabled{opacity:.55}.side-nav-disabled small{margin-left:auto;font-size:10px;font-weight:500}.sidebar-footer{display:flex;align-items:center;gap:9px;margin-top:auto;padding:12px 10px;border-top:1px solid var(--border);font-weight:700}.teacher-avatar{display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:#e0e7ff;color:#3730a3}.app-main{width:calc(100% - 236px);margin-left:236px}.topbar{display:flex;align-items:center;justify-content:space-between;height:64px;padding:0 34px;background:#fff;border-bottom:1px solid var(--border)}.topbar-context{font-weight:750}.topbar-actions{display:flex;align-items:center;gap:16px;color:var(--muted)}.notification{font-size:18px}.container{max-width:1280px;margin:0 auto;padding:32px 36px 56px}.login-shell{display:grid;min-height:100vh;place-items:center;padding:24px}.login-card{width:min(420px,100%);padding:28px;border:1px solid var(--border);border-radius:14px;background:#fff;box-shadow:var(--shadow)}
h1,h2,h3,p{margin-top:0}h1{margin-bottom:6px;font-size:29px;letter-spacing:-.035em}h2{font-size:17px}.eyebrow{margin-bottom:5px;color:var(--primary);font-size:12px;font-weight:800;letter-spacing:.08em}.meta,.page-summary{color:var(--muted)}.detail-header,.board-header,.page-heading{display:flex;align-items:flex-start;justify-content:space-between;gap:20px;margin-bottom:22px}.badges{display:flex;flex-wrap:wrap;gap:7px}.badge{display:inline-flex;padding:4px 8px;border-radius:6px;background:var(--soft);font-size:12px;font-weight:750}.badge.ai{background:var(--primary-soft);color:#1d4ed8}.badge.final{background:var(--success-soft);color:#166534}.card,.course-card,.group-card{margin-bottom:18px;padding:20px;border:1px solid var(--border);border-radius:13px;background:var(--surface);box-shadow:var(--shadow)}.tabs{display:flex;gap:8px;margin:25px 0 16px;border-bottom:1px solid var(--border)}.tab-button{padding:11px 13px;border:0;border-bottom:2px solid transparent;background:transparent;color:var(--muted);font:inherit;cursor:pointer}.tab-button.active{border-bottom-color:var(--primary);color:var(--primary);font-weight:800}.tab-panel{display:none}.tab-panel.active{display:block}.review-grid{display:grid;grid-template-columns:180px 1fr;gap:18px}.grade-card p{margin-bottom:3px;color:var(--muted)}.grade{font-size:50px;color:var(--primary)}.dimensions{padding-left:20px}.dimensions li{padding:10px 0;border-bottom:1px solid var(--border)}.dimensions li:last-child{border:0}.dimensions span,.rationale{color:var(--muted)}.metrics-strip{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:15px}.metrics-strip span{padding:6px 9px;border-radius:7px;background:var(--soft);color:#475569;font-size:12px}.conversation-list{display:grid;gap:10px}.conversation-card{border:1px solid var(--border);border-radius:11px;background:#fff;overflow:hidden}.conversation-card summary{display:grid;grid-template-columns:28px minmax(0,1fr) 180px 20px;align-items:center;gap:10px;padding:14px 16px;cursor:pointer;list-style:none}.conversation-card summary::-webkit-details-marker{display:none}.conversation-index{display:grid;place-items:center;width:24px;height:24px;border-radius:7px;background:var(--primary-soft);color:#1d4ed8;font-size:12px;font-weight:800}.conversation-prompt{overflow:hidden;white-space:nowrap;text-overflow:ellipsis}.conversation-prompt b{margin-right:8px;color:var(--primary)}.conversation-time{color:var(--muted);font-size:12px;text-align:right}.chevron{color:var(--muted);transition:transform .15s}.conversation-card[open] .chevron{transform:rotate(180deg)}.conversation-answer{padding:0 16px 16px;border-top:1px solid var(--border);background:#f8fbff}.answer-label{padding:11px 0 8px;color:#1d4ed8;font-weight:800;font-size:12px}.conversation-answer pre{margin:0;white-space:pre-wrap;word-break:break-word;font:13px/1.65 ui-monospace,Consolas,monospace}.code-workspace{display:grid;grid-template-columns:278px minmax(0,1fr);min-height:540px;overflow:hidden;border:1px solid var(--border);border-radius:13px;background:#fff;box-shadow:var(--shadow)}.code-explorer{padding:14px 10px;background:#fbfcfe;border-right:1px solid var(--border);overflow:auto}.explorer-title{display:flex;justify-content:space-between;padding:0 8px 10px;color:#475569;font-size:12px;font-weight:800}.explorer-title span{color:var(--muted)}.tree-directory summary,.tree-file{display:block;padding:5px 8px;border-radius:6px;color:#334155;cursor:pointer;text-decoration:none}.tree-directory summary{font-weight:700;list-style:none}.tree-directory summary::-webkit-details-marker{display:none}.tree-children{padding-left:14px}.tree-file{overflow:hidden;white-space:nowrap;text-overflow:ellipsis;font-size:13px}.tree-file:hover,.tree-file.selected{background:var(--primary-soft);color:#1d4ed8}.tree-file span{display:inline-block;width:18px;color:var(--muted)}.code-preview{min-width:0;background:#0f172a;color:#e2e8f0}.code-preview-header{display:flex;justify-content:space-between;gap:12px;padding:12px 16px;background:#172033;color:#cbd5e1;font:12px ui-monospace,Consolas,monospace}.code-preview pre{max-height:510px;overflow:auto;margin:0;padding:17px;white-space:pre-wrap;word-break:break-word;font:13px/1.65 ui-monospace,Consolas,monospace}.truncation-note{margin:0;padding:9px 16px;background:#78350f;color:#fef3c7}.screenshots{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px}.screenshots figure{margin:0;padding:10px;border:1px solid var(--border);border-radius:10px;background:#fff}.screenshots img{width:100%;max-height:260px;object-fit:contain;background:var(--soft)}.screenshots figcaption{overflow:hidden;margin-top:7px;color:var(--muted);font-size:12px;text-overflow:ellipsis;white-space:nowrap}.empty-state{color:var(--muted);text-align:center}.button{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:0 14px;border:1px solid var(--primary);border-radius:8px;background:var(--primary);color:#fff;font:inherit;font-weight:750;text-decoration:none;cursor:pointer}.back-link{display:inline-block;margin-top:20px;color:var(--primary);font-weight:750;text-decoration:none}.flash{margin:12px 36px;padding:10px 13px;border-radius:8px;background:#eff6ff;color:#1d4ed8}label{display:block;margin:10px 0 5px;font-weight:700}input,select{width:100%;padding:9px 10px;border:1px solid var(--border);border-radius:8px;font:inherit}form .button{margin-top:14px}.course-card-head,.group-card-head,.actions,.view-actions{display:flex;align-items:center}.course-card-head,.group-card-head{justify-content:space-between}.assign-table{width:100%;border-collapse:collapse}.assign-table th,.assign-table td{padding:12px 9px;text-align:left;border-top:1px solid var(--border)}.assign-table th{color:var(--muted)}.group-members{display:grid;grid-template-columns:repeat(auto-fill,minmax(218px,1fr));gap:12px}.member-cell{padding:15px;border:1px solid var(--border);border-radius:12px;background:var(--soft)}.member-cell-link{text-decoration:none}.member-info{display:flex;flex-direction:column;margin-bottom:10px}.student-no{color:var(--muted);font-size:12px}.student-name{font-weight:800}.progress-section{margin-bottom:18px;padding:18px;border:1px solid var(--border);border-radius:13px;background:#fff}.progress-bar{display:flex;height:10px;overflow:hidden;border-radius:99px;background:var(--soft)}.progress-fill{height:100%}.progress-fill.evaluated{background:var(--success)}.progress-fill.failed{background:#b91c1c}.progress-label{margin-top:9px;color:var(--muted)}
.session-group{margin:0 0 18px;padding:14px;border:1px solid var(--border);border-radius:13px;background:#fbfdff}.session-heading{display:flex;align-items:center;gap:9px;margin:0 2px 11px;font-weight:800}.session-heading code{max-width:50%;overflow:hidden;color:var(--muted);font:11px ui-monospace,Consolas,monospace;text-overflow:ellipsis;white-space:nowrap}.session-heading span{margin-left:auto;color:var(--muted);font-size:12px;font-weight:600}.text-button{padding:4px 0;border:0;background:transparent;color:var(--primary);font:inherit;font-weight:750;cursor:pointer}.text-button:disabled{opacity:.55;cursor:wait}.analytics-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.metric-card span{display:block;color:var(--muted)}.metric-card strong{display:block;margin-top:8px;color:var(--primary);font-size:44px;line-height:1}.stat-list{margin:0;padding:0;list-style:none}.stat-list li{display:flex;justify-content:space-between;padding:9px 0;border-bottom:1px solid var(--border)}.stat-list li:last-child{border-bottom:0}
@media(max-width:820px){.sidebar{position:static;width:100%;height:auto}.app-shell{display:block}.app-main{width:100%;margin:0}.side-nav{display:flex;overflow:auto}.sidebar-footer{display:none}.topbar{padding:0 18px}.container{padding:24px 16px}.detail-header,.board-header,.page-heading{flex-direction:column}.review-grid,.code-workspace,.analytics-grid{grid-template-columns:1fr}.code-explorer{max-height:240px;border-right:0;border-bottom:1px solid var(--border)}.conversation-card summary{grid-template-columns:28px minmax(0,1fr) 20px}.conversation-time{display:none}}
.dashboard-actions{display:flex;align-items:center;gap:9px}.button-small{min-height:32px;padding:0 11px;font-size:12px}.action-menu{position:relative}.action-menu summary{display:flex;align-items:center;gap:6px;min-height:32px;padding:0 10px;border:1px solid var(--border);border-radius:8px;background:#fff;color:#475569;cursor:pointer;font-size:12px;font-weight:750;list-style:none;white-space:nowrap}.action-menu summary::-webkit-details-marker{display:none}.action-menu[open] summary{border-color:#93c5fd;background:#eff6ff;color:#1d4ed8}.action-menu-popover{position:absolute;z-index:5;top:calc(100% + 6px);right:0;display:grid;min-width:172px;padding:6px;border:1px solid var(--border);border-radius:10px;background:#fff;box-shadow:0 14px 30px rgba(15,23,42,.14)}.action-menu-popover a{padding:8px 9px;border-radius:6px;color:#334155;text-decoration:none;font-size:13px;white-space:nowrap}.action-menu-popover a:hover{background:var(--primary-soft);color:#1d4ed8}@media(max-width:820px){.dashboard-actions{flex-wrap:wrap}.action-menu-popover{right:auto;left:0}}