:root{color-scheme:light;--bg:#f4f6fb;--surface:#fff;--surface-soft:#f8fafc;--text:#1f2937;--muted:#64748b;--line:#e2e8f0;--primary:#5a67d8;--primary-dark:#434ab8;--accent:#14b8a6;--warning:#f59e0b;--radius:8px;font-family:Inter,Segoe UI,PingFang SC,Microsoft YaHei,Arial,sans-serif}*{box-sizing:border-box}[hidden]{display:none!important}html{background:var(--bg)}body{color:var(--text);background:var(--bg);margin:0}a{color:inherit;text-decoration:none}.app-shell{grid-template-columns:248px minmax(0,1fr);min-height:100vh;display:grid}.sidebar{background:var(--surface);border-right:1px solid var(--line);height:100vh;padding:22px 18px;position:sticky;top:0}.brand{align-items:center;gap:12px;padding:10px 8px 22px;display:flex}.brand-mark{border-radius:var(--radius);color:#fff;background:var(--primary);place-items:center;width:38px;height:38px;font-weight:800;display:grid}.brand strong,.brand small{display:block}.brand small{color:var(--muted);margin-top:3px;font-size:12px}.side-nav{gap:6px;display:grid}.side-nav a{border-radius:var(--radius);color:#526173;padding:12px 14px;font-weight:650}.side-nav a:hover,.side-nav a.active{color:var(--primary);background:#eef2ff}.main{min-width:0}.topbar{color:#fff;background:var(--primary);justify-content:space-between;align-items:center;gap:18px;min-height:116px;padding:28px 32px;display:flex}.topbar h1{letter-spacing:0;margin:0;font-size:38px;line-height:1.15}.eyebrow{color:#ffffffbf;margin:0 0 8px;font-size:13px;font-weight:700}.top-link,.button{border-radius:var(--radius);border:1px solid #0000;justify-content:center;align-items:center;min-height:40px;padding:9px 15px;font-weight:750;display:inline-flex}.top-link{color:#fff;background:#ffffff1f;border-color:#ffffff59}.content{width:min(1180px,100% - 40px);margin:0 auto;padding:28px 0 56px}.grid{gap:20px;display:grid}.grid.cols-2{grid-template-columns:minmax(0,1fr) minmax(300px,.45fr);align-items:start}.grid.cols-3{grid-template-columns:repeat(3,minmax(0,1fr))}.card,.panel{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:0 10px 26px #0f172a0d}.card{padding:20px}.panel-header{border-bottom:1px solid var(--line);padding:18px 20px}.panel-body{padding:20px}.stat{align-items:center;gap:14px;display:flex}.stat-icon{border-radius:var(--radius);color:#fff;background:var(--primary);flex:none;place-items:center;width:44px;height:44px;font-weight:800;display:grid}.stat h3,.card h2,.card h3,.panel h2,.panel h3{margin:0}.stat p,.muted{color:var(--muted)}.stat p{margin:2px 0 0}.searchbar{width:100%;min-height:44px;color:var(--text);border:1px solid var(--line);border-radius:var(--radius);font:inherit;background:#fff;padding:10px 13px}.filter-row{flex-wrap:wrap;align-items:center;gap:10px;margin-bottom:18px;display:flex}.tag,.pill{color:#475569;background:#f1f5f9;border-radius:999px;align-items:center;gap:6px;padding:5px 9px;font-size:12px;font-weight:700;display:inline-flex}.course-list{gap:14px;display:grid}.course-card{border:1px solid var(--line);border-radius:var(--radius);background:#fff;gap:12px;padding:18px;display:grid}.course-card:hover{border-color:#c7d2fe}.admin-course-button{width:100%;color:inherit;text-align:left;font:inherit;cursor:pointer}.admin-course-button[data-active=true]{background:#eef2ff;border-color:#a5b4fc}.course-card h2{margin:0;font-size:22px}.course-meta{flex-wrap:wrap;gap:8px;display:flex}.course-summary{color:#475569;margin:0;line-height:1.75}.button{color:#fff;background:var(--primary)}.button.secondary{color:var(--primary);background:#eef2ff;border-color:#c7d2fe}.section-stack{gap:12px;display:grid}details.resource-section{border:1px solid var(--line);border-radius:var(--radius);background:#fff;overflow:hidden}details.resource-section summary{cursor:pointer;padding:15px 17px;font-weight:800;list-style:none}details.resource-section summary::-webkit-details-marker{display:none}.section-note{color:var(--muted);margin:-6px 17px 14px}.file-list{background:var(--line);gap:1px;display:grid}.file-row{background:#fff;grid-template-columns:minmax(0,1fr) auto;gap:12px;padding:13px 16px;display:grid}.file-row strong{overflow-wrap:anywhere;display:block}.file-row small{color:var(--muted);margin-top:4px;display:block}.empty{color:var(--muted);background:var(--surface-soft);border-radius:var(--radius);padding:18px}.admin-form,.admin-section-body,.admin-file-list{gap:12px;display:grid}.admin-field{color:#475569;gap:6px;font-size:13px;font-weight:750;display:grid}.admin-field input,.admin-field textarea{width:100%;min-height:40px;color:var(--text);border:1px solid var(--line);border-radius:var(--radius);font:inherit;background:#fff;padding:9px 11px;font-weight:500}.admin-field textarea{resize:vertical;min-height:96px}.admin-section-body{padding:0 16px 16px}.admin-file-row{border:1px solid var(--line);border-radius:var(--radius);background:var(--surface-soft);gap:10px;padding:12px;display:grid}.hero-note{color:#fff;background:var(--primary-dark);border-radius:var(--radius);margin:-18px 0 24px;padding:14px 18px}@media (width<=900px){.app-shell{display:block}.sidebar{height:auto;padding:14px;position:static}.side-nav{grid-template-columns:repeat(4,minmax(0,1fr))}.side-nav a{text-align:center;padding:10px 6px}.topbar{padding:24px 20px}.topbar h1{font-size:28px}.content{width:min(100% - 28px,1180px)}.grid.cols-2,.grid.cols-3{grid-template-columns:1fr}}