:root{--primary: #1a73e8;--primary-dark: #1557b0;--primary-light: #e8f0fe;--success: #0d904f;--success-light: #e6f4ea;--warning: #f9ab00;--warning-light: #fef7e0;--danger: #d93025;--danger-light: #fce8e6;--info: #1967d2;--bg: #f0f2f5;--bg-white: #ffffff;--text: #202124;--text-secondary: #5f6368;--text-muted: #9aa0a6;--border: #dadce0;--border-light: #e8eaed;--shadow: 0 1px 3px rgba(0,0,0,.1);--shadow-md: 0 4px 6px rgba(0,0,0,.07);--shadow-lg: 0 10px 25px rgba(0,0,0,.1);--radius: 8px;--radius-sm: 4px;--radius-lg: 12px;--transition: .2s ease}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text);line-height:1.6;-webkit-font-smoothing:antialiased}a{color:var(--primary);text-decoration:none}a:hover{text-decoration:underline}.app-layout{display:flex;min-height:100vh}.sidebar{width:240px;background:linear-gradient(180deg,#1a3a5c,#1a5276);color:#fff;flex-shrink:0;display:flex;flex-direction:column;position:fixed;top:0;left:0;bottom:0;z-index:100}.sidebar-logo{padding:20px 24px;border-bottom:1px solid rgba(255,255,255,.1);display:flex;align-items:center;gap:12px}.sidebar-logo .logo-icon{width:36px;height:36px;background:#fff3;border-radius:8px;display:flex;align-items:center;justify-content:center;font-size:18px}.sidebar-logo h1{font-size:15px;font-weight:600;line-height:1.3}.sidebar-nav{flex:1;padding:12px 0;overflow-y:auto}.sidebar-section{padding:16px 24px 8px;font-size:11px;text-transform:uppercase;color:#ffffff80;letter-spacing:1px}.sidebar-link{display:flex;align-items:center;gap:12px;padding:10px 24px;color:#ffffffbf;font-size:14px;transition:var(--transition);border-left:3px solid transparent;cursor:pointer}.sidebar-link:hover{background:#ffffff14;color:#fff;text-decoration:none}.sidebar-link.active{background:#ffffff1f;color:#fff;border-left-color:#4fc3f7}.sidebar-link .icon{font-size:18px;width:24px;text-align:center}.main-content{flex:1;margin-left:240px;min-height:100vh}.page-header{background:var(--bg-white);padding:16px 32px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:50}.page-header h2{font-size:20px;font-weight:600}.page-body{padding:24px 32px}.card{background:var(--bg-white);border-radius:var(--radius-lg);box-shadow:var(--shadow);border:1px solid var(--border-light);padding:24px;margin-bottom:20px}.card-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px;padding-bottom:16px;border-bottom:1px solid var(--border-light)}.card-header h3{font-size:16px;font-weight:600}.card-grid{display:grid;gap:20px}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;margin-bottom:24px}.stat-card{background:var(--bg-white);border-radius:var(--radius-lg);padding:20px;box-shadow:var(--shadow);border:1px solid var(--border-light);display:flex;align-items:center;gap:16px}.stat-icon{width:48px;height:48px;border-radius:var(--radius);display:flex;align-items:center;justify-content:center;font-size:22px;flex-shrink:0}.stat-icon.blue{background:var(--primary-light);color:var(--primary)}.stat-icon.green{background:var(--success-light);color:var(--success)}.stat-icon.orange{background:var(--warning-light);color:var(--warning)}.stat-icon.red{background:var(--danger-light);color:var(--danger)}.stat-info .stat-value{font-size:24px;font-weight:700;line-height:1.2}.stat-info .stat-label{font-size:13px;color:var(--text-secondary);margin-top:2px}.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;border:1px solid transparent;border-radius:var(--radius-sm);font-size:14px;font-weight:500;cursor:pointer;transition:var(--transition);white-space:nowrap;font-family:inherit;line-height:1.5}.btn:hover{opacity:.9}.btn-primary{background:var(--primary);color:#fff}.btn-success{background:var(--success);color:#fff}.btn-danger{background:var(--danger);color:#fff}.btn-warning{background:var(--warning);color:#fff}.btn-outline{background:transparent;border-color:var(--border);color:var(--text)}.btn-outline:hover{background:var(--bg)}.btn-sm{padding:4px 10px;font-size:12px}.btn-lg{padding:12px 24px;font-size:16px}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-group{display:flex;gap:8px;flex-wrap:wrap}.badge{display:inline-flex;align-items:center;padding:2px 10px;border-radius:12px;font-size:12px;font-weight:500;line-height:1.8}.badge-success{background:var(--success-light);color:var(--success)}.badge-warning{background:var(--warning-light);color:#e37400}.badge-danger{background:var(--danger-light);color:var(--danger)}.badge-info{background:var(--primary-light);color:var(--primary)}.badge-default{background:#f1f3f4;color:var(--text-secondary)}.table-container{overflow-x:auto}table{width:100%;border-collapse:collapse}table th,table td{padding:12px 16px;text-align:left;border-bottom:1px solid var(--border-light);font-size:14px}table th{background:#fafafa;font-weight:600;color:var(--text-secondary);white-space:nowrap}table tr:hover{background:#f8f9fa}table td .actions{display:flex;gap:6px}.form-group{margin-bottom:16px}.form-group label{display:block;font-size:13px;font-weight:500;color:var(--text-secondary);margin-bottom:6px}.form-control{width:100%;padding:8px 12px;border:1px solid var(--border);border-radius:var(--radius-sm);font-size:14px;font-family:inherit;transition:var(--transition);background:#fff}.form-control:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 2px #1a73e826}select.form-control{cursor:pointer}textarea.form-control{resize:vertical;min-height:80px}.form-row{display:grid;grid-template-columns:1fr 1fr;gap:16px}.form-row-3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:16px}.modal-overlay{position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;display:flex;align-items:center;justify-content:center;z-index:1000;animation:fadeIn .2s ease}.modal{background:var(--bg-white);border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);width:90%;max-width:640px;max-height:85vh;overflow-y:auto}.modal-header{display:flex;align-items:center;justify-content:space-between;padding:16px 24px;border-bottom:1px solid var(--border-light)}.modal-header h3{font-size:16px;font-weight:600}.modal-close{background:none;border:none;font-size:20px;cursor:pointer;color:var(--text-secondary);width:32px;height:32px;display:flex;align-items:center;justify-content:center;border-radius:50%;transition:var(--transition)}.modal-close:hover{background:var(--bg)}.modal-body{padding:24px}.modal-footer{padding:16px 24px;border-top:1px solid var(--border-light);display:flex;justify-content:flex-end;gap:8px}.search-bar{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin-bottom:20px}.search-bar .form-control{max-width:280px}.pagination{display:flex;align-items:center;justify-content:center;gap:8px;margin-top:20px}.pagination button{padding:6px 12px;border:1px solid var(--border);background:#fff;border-radius:var(--radius-sm);cursor:pointer;font-size:13px;transition:var(--transition)}.pagination button:hover{background:var(--bg)}.pagination button.active{background:var(--primary);color:#fff;border-color:var(--primary)}.pagination button:disabled{opacity:.4;cursor:not-allowed}.pagination span{font-size:13px;color:var(--text-secondary)}.tabs{display:flex;border-bottom:2px solid var(--border-light);margin-bottom:20px}.tab{padding:10px 20px;font-size:14px;font-weight:500;cursor:pointer;color:var(--text-secondary);border-bottom:2px solid transparent;margin-bottom:-2px;transition:var(--transition);background:none;border-top:none;border-left:none;border-right:none;font-family:inherit}.tab:hover{color:var(--primary)}.tab.active{color:var(--primary);border-bottom-color:var(--primary)}.empty-state{text-align:center;padding:48px 24px;color:var(--text-secondary)}.empty-state .empty-icon{font-size:48px;margin-bottom:12px;opacity:.5}.empty-state p{font-size:14px}.certificate-preview{width:100%;max-width:700px;margin:0 auto;border:2px solid var(--border);padding:40px;position:relative;background:#fffef5;min-height:450px;border-radius:var(--radius)}.certificate-preview .cert-title{text-align:center;font-size:28px;font-weight:700;color:#c62828;margin-bottom:30px;font-family:SimHei,STHeiti,serif}.certificate-preview .cert-body{text-align:center;font-size:16px;line-height:2.5}.certificate-preview .cert-anti-fake{position:absolute;bottom:20px;right:30px;font-size:12px;color:#999;font-family:monospace;background:#f5f5f5;padding:4px 8px;border-radius:4px}.role-tag{display:inline-block;padding:2px 8px;border-radius:4px;font-size:12px}.role-student{background:#e3f2fd;color:#1565c0}.role-teacher{background:#f3e5f5;color:#7b1fa2}.role-admin{background:#fff3e0;color:#e65100}.role-school-admin{background:#e8f5e9;color:#2e7d32}.loading{text-align:center;padding:40px;color:var(--text-secondary)}.spinner{width:32px;height:32px;border:3px solid var(--border);border-top-color:var(--primary);border-radius:50%;animation:spin .8s linear infinite;margin:0 auto 12px}@keyframes spin{to{transform:rotate(360deg)}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.toast{position:fixed;top:20px;right:20px;z-index:2000;padding:12px 20px;border-radius:var(--radius);color:#fff;font-size:14px;box-shadow:var(--shadow-lg);animation:slideIn .3s ease;max-width:400px}.toast.success{background:var(--success)}.toast.error{background:var(--danger)}.toast.info{background:var(--primary)}@keyframes slideIn{0%{transform:translate(100%);opacity:0}to{transform:translate(0);opacity:1}}@media (max-width: 768px){.sidebar{width:200px}.main-content{margin-left:200px}.page-body{padding:16px}.form-row,.form-row-3{grid-template-columns:1fr}.stats-grid{grid-template-columns:repeat(2,1fr)}.page-header{padding:12px 16px}}