*{margin:0;padding:0;box-sizing:border-box}:root{--primary: #4f46e5;--primary-light: #818cf8;--primary-dark: #3730a3;--success: #10b981;--warning: #f59e0b;--danger: #ef4444;--bg: #f8fafc;--card: #ffffff;--text: #1e293b;--text-light: #64748b;--border: #e2e8f0;--radius: 8px;--shadow: 0 1px 3px rgba(0,0,0,.08)}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text);line-height:1.6}.app-layout{display:flex;min-height:100vh}.sidebar{width:220px;background:var(--primary-dark);color:#fff;padding:20px 0;display:flex;flex-direction:column}.sidebar-logo{padding:0 20px 20px;font-size:18px;font-weight:700;border-bottom:1px solid rgba(255,255,255,.15);margin-bottom:10px}.sidebar-nav{flex:1}.sidebar-nav a{display:block;padding:10px 20px;color:#fffc;text-decoration:none;font-size:14px;transition:all .2s}.sidebar-nav a:hover,.sidebar-nav a.active{background:#ffffff1f;color:#fff}.main-content{flex:1;padding:24px;overflow-y:auto}.main-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:24px;padding-bottom:16px;border-bottom:1px solid var(--border)}.main-header h1{font-size:22px}.card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px;margin-bottom:16px}.stats-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:16px;margin-bottom:24px}.stat-card{background:var(--card);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);text-align:center}.stat-card .value{font-size:32px;font-weight:700;color:var(--primary)}.stat-card .label{font-size:13px;color:var(--text-light);margin-top:4px}.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;border:none;border-radius:var(--radius);cursor:pointer;font-size:14px;font-weight:500;transition:all .2s;text-decoration:none}.btn-primary{background:var(--primary);color:#fff}.btn-primary:hover{background:var(--primary-dark)}.btn-success{background:var(--success);color:#fff}.btn-danger{background:var(--danger);color:#fff}.btn-outline{background:transparent;color:var(--text-light);border:1px solid var(--border)}.btn-outline:hover{border-color:var(--primary);color:var(--primary)}.btn-sm{padding:4px 10px;font-size:13px}.form-group{margin-bottom:16px}.form-group label{display:block;margin-bottom:6px;font-weight:500;font-size:14px}.form-control{width:100%;padding:8px 12px;border:1px solid var(--border);border-radius:var(--radius);font-size:14px;outline:none;transition:border .2s}.form-control:focus{border-color:var(--primary)}textarea.form-control{min-height:100px;resize:vertical}select.form-control{-webkit-appearance:auto;-moz-appearance:auto;appearance:auto}.table-container{overflow-x:auto}table{width:100%;border-collapse:collapse}th,td{padding:10px 12px;text-align:left;border-bottom:1px solid var(--border);font-size:14px}th{font-weight:600;color:var(--text-light);font-size:13px}.progress-bar{height:8px;background:var(--border);border-radius:4px;overflow:hidden}.progress-bar .fill{height:100%;background:var(--primary);transition:width .3s}.badge{display:inline-block;padding:2px 8px;border-radius:12px;font-size:12px;font-weight:500}.badge-success{background:#d1fae5;color:#065f46}.badge-warning{background:#fef3c7;color:#92400e}.badge-info{background:#dbeafe;color:#1e40af}.login-page{display:flex;align-items:center;justify-content:center;min-height:100vh;background:linear-gradient(135deg,var(--primary) 0%,var(--primary-dark) 100%)}.login-card{background:#fff;border-radius:12px;padding:40px;width:380px;box-shadow:0 20px 60px #00000026}.login-card h2{text-align:center;margin-bottom:24px;color:var(--text)}.login-card .btn{width:100%;justify-content:center;padding:10px}.quiz-option{display:flex;align-items:center;gap:10px;padding:12px 16px;border:2px solid var(--border);border-radius:var(--radius);margin-bottom:8px;cursor:pointer;transition:all .2s}.quiz-option:hover{border-color:var(--primary-light)}.quiz-option.selected{border-color:var(--primary);background:#eef2ff}.quiz-option.correct{border-color:var(--success);background:#d1fae5}.quiz-option.wrong{border-color:var(--danger);background:#fee2e2}.quiz-option input{display:none}.media-container{width:100%;aspect-ratio:16/9;background:#000;border-radius:var(--radius);overflow:hidden;margin-bottom:16px}.media-container iframe{width:100%;height:100%;border:none}.flex{display:flex}.flex-between{display:flex;justify-content:space-between;align-items:center}.gap-8{gap:8px}.gap-16{gap:16px}.mt-16{margin-top:16px}.mb-16{margin-bottom:16px}.text-center{text-align:center}.text-muted{color:var(--text-light)}.error-msg{color:var(--danger);font-size:13px;margin-top:4px}.loading,.empty-state{text-align:center;padding:40px;color:var(--text-light)}.dialog-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#0006;display:flex;align-items:center;justify-content:center;z-index:100}.dialog{background:#fff;border-radius:12px;padding:24px;width:480px;max-width:90vw;max-height:80vh;overflow-y:auto}.dialog h3{margin-bottom:16px}