:root{--primary:#0052d9;--primary-light:#e8f0fe;--success:#00b42a;--success-light:#e8f8ec;--danger:#e34d59;--warning:#ff7d00;--text-primary:#1d2129;--text-secondary:#4e5969;--text-tertiary:#86909c;--bg-page:#f5f6f8;--bg-white:#fff;--border:#e5e6eb;--border-light:#f2f3f5;--radius:8px;--radius-lg:12px;--shadow-sm:0 1px 2px #0000000a;--shadow:0 2px 8px #0000000f;--shadow-lg:0 4px 16px #00000014;--transition:all .2s ease}*{box-sizing:border-box;margin:0;padding:0}body{color:var(--text-primary);background:var(--bg-page);-webkit-font-smoothing:antialiased;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;font-size:14px}a{color:var(--primary);text-decoration:none}.app-header{background:var(--bg-white);border-bottom:1px solid var(--border);z-index:100;align-items:center;height:56px;padding:0 24px;display:flex;position:fixed;top:0;left:0;right:0}.header-left{align-items:center;display:flex}.logo{color:var(--text-primary);letter-spacing:-.3px;font-size:16px;font-weight:700}.header-nav{flex:1;gap:4px;margin-left:48px;display:flex}.nav-link{color:var(--text-secondary);transition:var(--transition);border-radius:6px;padding:6px 16px;font-size:14px}.nav-link:hover{background:var(--bg-page);color:var(--text-primary)}.nav-link.active{background:var(--primary-light);color:var(--primary);font-weight:500}.header-right{align-items:center;gap:16px;display:flex}.teacher-name{color:var(--text-secondary);font-size:13px}.logout-btn{border:1px solid var(--border);background:var(--bg-white);color:var(--text-secondary);cursor:pointer;transition:var(--transition);border-radius:6px;padding:5px 14px;font-size:13px}.logout-btn:hover{border-color:var(--danger);color:var(--danger)}main.has-header{padding-top:56px}.page{max-width:960px;margin:0 auto;padding:24px}.page-wide{max-width:1200px}.card{background:var(--bg-white);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);border:1px solid var(--border-light);margin-bottom:16px;padding:24px}.card-title{color:var(--text-primary);border-bottom:1px solid var(--border-light);margin-bottom:16px;padding-bottom:12px;font-size:16px;font-weight:600}.btn{cursor:pointer;transition:var(--transition);border:1px solid #0000;border-radius:6px;justify-content:center;align-items:center;gap:6px;padding:8px 20px;font-size:14px;font-weight:500;display:inline-flex}.btn-primary{background:var(--primary);color:#fff;border-color:var(--primary)}.btn-primary:hover{background:#0042b0}.btn-primary:disabled{cursor:not-allowed;background:#b4cbf0;border-color:#b4cbf0}.btn-success{background:var(--success);color:#fff;border-color:var(--success)}.btn-success:hover{background:#009a23}.btn-outline{background:var(--bg-white);color:var(--text-primary);border-color:var(--border)}.btn-outline:hover{border-color:var(--primary);color:var(--primary)}.btn-danger{background:var(--bg-white);color:var(--danger);border-color:var(--danger)}.btn-danger:hover{background:var(--danger);color:#fff}.btn-sm{padding:4px 12px;font-size:12px}.btn-lg{padding:12px 32px;font-size:16px}.form-group{margin-bottom:20px}.form-label{color:var(--text-primary);margin-bottom:8px;font-size:14px;font-weight:500;display:block}.form-input{border:1px solid var(--border);width:100%;height:44px;color:var(--text-primary);background:var(--bg-white);transition:var(--transition);border-radius:6px;outline:none;padding:0 14px;font-size:14px}.form-input:focus{border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-light)}.form-input::placeholder{color:var(--text-tertiary)}.form-hint{color:var(--text-tertiary);margin-top:6px;font-size:12px}.form-error{color:var(--danger);margin-top:6px;font-size:12px}.tag{background:var(--primary-light);color:var(--primary);border-radius:4px;align-items:center;padding:2px 10px;font-size:12px;font-weight:500;display:inline-flex}.tag-success{background:var(--success-light);color:var(--success)}.tag-sm{padding:1px 6px;font-size:11px}.empty-state{text-align:center;color:var(--text-tertiary);padding:60px 20px}.empty-state-icon{opacity:.4;margin-bottom:12px;font-size:48px}.empty-state-text{font-size:15px}.loading-spinner{justify-content:center;padding:60px 20px;display:flex}.spinner{border:3px solid var(--border);border-top-color:var(--primary);border-radius:50%;width:32px;height:32px;animation:.7s linear infinite spin}@keyframes spin{to{transform:rotate(360deg)}}.student-card{background:var(--bg-white);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);border:1px solid var(--border-light);cursor:pointer;transition:var(--transition);align-items:center;margin-bottom:12px;padding:20px 24px;display:flex}.student-card:hover{box-shadow:var(--shadow);border-color:var(--primary)}.student-avatar{background:var(--primary-light);width:44px;height:44px;color:var(--primary);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;margin-right:16px;font-size:18px;font-weight:600;display:flex}.student-info{flex:1;min-width:0}.student-name{color:var(--text-primary);font-size:16px;font-weight:600}.student-meta{color:var(--text-tertiary);margin-top:2px;font-size:13px}.student-subjects{flex-wrap:wrap;gap:6px;margin-top:6px;display:flex}.student-badge{flex-shrink:0;align-items:center;gap:6px;margin-left:16px;display:flex}.five-badge{background:var(--success-light);color:var(--success);border-radius:20px;align-items:center;padding:4px 12px;font-size:13px;font-weight:600;display:inline-flex}.subject-grid{grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:10px;display:grid}.subject-btn{border:1px solid var(--border);border-radius:var(--radius);background:var(--bg-white);color:var(--text-primary);cursor:pointer;transition:var(--transition);text-align:left;padding:10px 14px;font-size:13px;line-height:1.4;position:relative}.subject-btn:hover{border-color:var(--primary)}.subject-btn.selected{background:var(--success);color:#fff;border-color:var(--success);font-weight:600}.count-btn{border-radius:var(--radius);border:1px solid var(--border);background:var(--bg-white);width:48px;height:48px;color:var(--text-primary);cursor:pointer;transition:var(--transition);font-size:18px;font-weight:600;position:relative}.count-btn:hover{border-color:var(--primary)}.count-btn.selected{background:var(--success);color:#fff;border-color:var(--success)}.category-tabs{flex-wrap:wrap;gap:6px;margin-bottom:16px;display:flex}.category-tab{border:1px solid var(--border);background:var(--bg-white);color:var(--text-secondary);cursor:pointer;transition:var(--transition);border-radius:20px;padding:5px 14px;font-size:13px}.category-tab:hover{border-color:var(--primary);color:var(--primary)}.category-tab.active{background:var(--primary);color:#fff;border-color:var(--primary)}.stats-row{grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;margin-bottom:24px;display:grid}.stat-card{background:var(--bg-white);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);border:1px solid var(--border-light);text-align:center;padding:24px}.stat-value{color:var(--text-primary);font-size:36px;font-weight:700}.stat-label{color:var(--text-tertiary);margin-top:4px;font-size:13px}.bar-chart{flex-direction:column;gap:8px;display:flex}.bar-row{align-items:center;gap:12px;display:flex}.bar-label{width:160px;color:var(--text-secondary);text-align:right;flex-shrink:0;font-size:13px}.bar-track{background:var(--bg-page);border-radius:4px;flex:1;height:24px;overflow:hidden}.bar-fill{background:var(--success);border-radius:4px;align-items:center;height:100%;padding:0 8px;transition:width .5s;display:flex}.bar-value{color:#fff;font-size:12px;font-weight:600}.data-table{border-collapse:collapse;width:100%}.data-table th{text-align:left;color:var(--text-tertiary);border-bottom:1px solid var(--border);background:var(--bg-page);padding:12px 16px;font-size:13px;font-weight:500}.data-table td{border-bottom:1px solid var(--border-light);padding:12px 16px;font-size:14px}.data-table tr:hover td{background:var(--bg-page)}.upload-zone{border:2px dashed var(--border);border-radius:var(--radius-lg);text-align:center;color:var(--text-tertiary);cursor:pointer;transition:var(--transition);padding:40px}.upload-zone:hover{border-color:var(--primary);color:var(--primary);background:var(--primary-light)}.upload-grid{grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:12px;margin-top:16px;display:grid}.upload-item{border:1px solid var(--border);border-radius:var(--radius);position:relative;overflow:hidden}.upload-item img{object-fit:cover;width:100%;height:140px}.upload-item-info{color:var(--text-secondary);padding:8px 12px;font-size:12px}.upload-item-del{color:#fff;cursor:pointer;background:#00000080;border:none;border-radius:50%;justify-content:center;align-items:center;width:24px;height:24px;font-size:14px;display:flex;position:absolute;top:4px;right:4px}.login-page{background:linear-gradient(135deg,#f5f6f8 0%,#e8f0fe 100%);justify-content:center;align-items:center;min-height:100vh;display:flex}.login-card{background:var(--bg-white);width:400px;box-shadow:var(--shadow-lg);border-radius:16px;padding:48px 40px}.login-logo{text-align:center;margin-bottom:32px}.login-logo h1{color:var(--text-primary);font-size:22px;font-weight:700}.login-logo p{color:var(--text-tertiary);margin-top:6px;font-size:13px}.steps{border-bottom:1px solid var(--border-light);gap:24px;margin-bottom:24px;padding-bottom:16px;display:flex}.step{color:var(--text-tertiary);align-items:center;gap:8px;font-size:14px;display:flex}.step-num{background:var(--bg-page);border-radius:50%;justify-content:center;align-items:center;width:24px;height:24px;font-size:12px;font-weight:600;display:flex}.step.active{color:var(--primary);font-weight:500}.step.active .step-num{background:var(--primary);color:#fff}.step.done{color:var(--success)}.step.done .step-num{background:var(--success);color:#fff}.toast{z-index:200;border-radius:6px;padding:10px 24px;font-size:14px;animation:.2s fadeIn;position:fixed;top:72px;left:50%;transform:translate(-50%)}.toast-success{background:var(--success);color:#fff}.toast-error{background:var(--danger);color:#fff}@keyframes fadeIn{0%{opacity:0;transform:translate(-50%)translateY(-8px)}to{opacity:1;transform:translate(-50%)translateY(0)}}