/* ==========================================================================
   课堂管理平台 · 公共样式
   ========================================================================== */
:root {
  --primary:#4f46e5; --primary-light:#eef2ff; --success:#10b981;
  --warning:#f59e0b; --danger:#ef4444; --bg:#f8fafc; --card:#fff;
  --text:#1e293b; --text-light:#64748b; --border:#e2e8f0;
  --radius:12px; --shadow:0 1px 3px rgba(0,0,0,.06),0 1px 2px rgba(0,0,0,.04);
  --shadow-lg:0 10px 25px rgba(0,0,0,.08);
}
*{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;min-height:100vh}

/* 按钮 */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:11px 20px;border:none;border-radius:10px;font-size:14px;font-weight:600;font-family:inherit;cursor:pointer;transition:all .2s;text-decoration:none}
.btn-primary{background:linear-gradient(135deg,#6366f1,#8b5cf6);color:#fff;box-shadow:0 4px 12px rgba(99,102,241,.3)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 6px 18px rgba(99,102,241,.4)}
.btn-block{width:100%}
.btn-sm{padding:7px 14px;font-size:13px}
.btn-outline{background:#fff;border:1.5px solid var(--border);color:var(--text)}
.btn-outline:hover{border-color:var(--primary);color:var(--primary);background:var(--primary-light)}
.btn-ghost{background:transparent;color:var(--text-light)}
.btn-ghost:hover{background:#f1f5f9;color:var(--text)}
.btn-ai{background:linear-gradient(135deg,#8b5cf6,#ec4899);color:#fff;box-shadow:0 4px 12px rgba(139,92,246,.3)}
.btn-ai:hover{transform:translateY(-1px);box-shadow:0 6px 18px rgba(139,92,246,.4)}

/* 表单 */
.form-group{margin-bottom:16px}
.form-group label{display:block;font-size:13px;font-weight:600;margin-bottom:6px;color:var(--text)}
.form-group input,.form-group select,.form-group textarea{width:100%;padding:11px 14px;border:1.5px solid var(--border);border-radius:10px;font-size:14px;font-family:inherit;transition:all .2s;background:#fff;color:var(--text)}
.form-group input:focus,.form-group select:focus,.form-group textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(79,70,229,.1)}
.form-group textarea{resize:vertical;min-height:80px}

/* 卡片 */
.card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);border:1px solid var(--border);padding:22px;margin-bottom:18px}
.card-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px;flex-wrap:wrap;gap:10px}
.card-title{font-size:16px;font-weight:700;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.page-title{font-size:24px;font-weight:800;margin-bottom:6px}
.page-sub{font-size:14px;color:var(--text-light);margin-bottom:24px}

/* 顶部导航 */
.topbar{background:#fff;border-bottom:1px solid var(--border);padding:0 24px;height:62px;display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:100}
.topbar-left{display:flex;align-items:center;gap:12px}
.topbar-logo{width:36px;height:36px;border-radius:10px;background:linear-gradient(135deg,#6366f1,#8b5cf6);display:flex;align-items:center;justify-content:center;font-size:18px;cursor:pointer}
.topbar-title{font-size:16px;font-weight:700}
.topbar-right{display:flex;align-items:center;gap:14px}
.user-chip{display:flex;align-items:center;gap:8px;padding:6px 12px 6px 6px;background:#f8fafc;border-radius:999px;font-size:13px;font-weight:600}
.avatar{width:28px;height:28px;border-radius:50%;background:linear-gradient(135deg,#6366f1,#8b5cf6);color:#fff;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700}
.badge-role{font-size:11px;padding:2px 8px;border-radius:999px;background:var(--primary-light);color:var(--primary);font-weight:700}
.main{max-width:1200px;margin:0 auto;padding:28px 24px 80px}

/* 标签 */
.tag{display:inline-flex;align-items:center;gap:4px;padding:3px 10px;border-radius:999px;font-size:12px;font-weight:600;background:#f1f5f9;color:var(--text-light)}
.tag-blue{background:var(--primary-light);color:var(--primary)}
.tag-green{background:#d1fae5;color:#059669}
.tag-orange{background:#fef3c7;color:#d97706}
.tag-red{background:#fee2e2;color:#dc2626}
.tag-purple{background:#f3e8ff;color:#7c3aed}

/* 空状态 */
.empty{text-align:center;padding:48px 20px;color:var(--text-light)}
.empty .icon{font-size:44px;margin-bottom:12px;opacity:.5}
.empty p{font-size:14px}

/* 课程卡片 */
.lesson-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.lesson-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:20px;cursor:pointer;transition:all .2s;position:relative;overflow:hidden}
.lesson-card::before{content:'';position:absolute;top:0;left:0;right:0;height:4px;background:linear-gradient(90deg,#6366f1,#8b5cf6);opacity:0;transition:opacity .2s}
.lesson-card:hover{box-shadow:var(--shadow-lg);transform:translateY(-3px);border-color:#c7d2fe}
.lesson-card:hover::before{opacity:1}
.lesson-card h3{font-size:16px;font-weight:700;margin-bottom:8px}
.lesson-card .desc{font-size:13px;color:var(--text-light);margin-bottom:14px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;min-height:40px}
.lesson-meta{display:flex;gap:8px;flex-wrap:wrap;font-size:12px;color:var(--text-light)}

/* 任务项 */
.task-item{border:1px solid var(--border);border-radius:10px;padding:16px;margin-bottom:12px;transition:all .2s;background:#fff}
.task-item:hover{border-color:#c7d2fe;box-shadow:var(--shadow)}
.task-item-header{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:8px}
.task-item-title{font-size:15px;font-weight:700;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.task-desc{font-size:13px;color:var(--text-light);margin-bottom:10px}
.task-actions{display:flex;gap:8px;flex-wrap:wrap;align-items:center}

/* 资料项 */
.material-item{display:flex;align-items:center;gap:12px;padding:12px 14px;border:1px solid var(--border);border-radius:10px;margin-bottom:8px;background:#fff;transition:all .2s}
.material-item:hover{background:#f8fafc;border-color:#c7d2fe}
.material-icon{width:38px;height:38px;border-radius:9px;display:flex;align-items:center;justify-content:center;font-size:18px;flex-shrink:0;background:var(--primary-light)}
.material-info{flex:1;min-width:0}
.material-name{font-size:14px;font-weight:600;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.material-meta{font-size:12px;color:var(--text-light)}

/* 弹窗 */
.modal-mask{display:none;position:fixed;inset:0;background:rgba(15,23,42,.5);backdrop-filter:blur(2px);z-index:1000;align-items:center;justify-content:center;padding:20px}
.modal-mask.show{display:flex}
.modal{background:#fff;border-radius:16px;width:100%;max-width:620px;max-height:88vh;overflow-y:auto;box-shadow:0 25px 60px rgba(0,0,0,.3);animation:slideUp .25s ease}
.modal-header{padding:20px 24px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;background:#fff;border-radius:16px 16px 0 0;z-index:10}
.modal-header h3{font-size:17px;font-weight:700}
.modal-close{background:none;border:none;font-size:22px;cursor:pointer;color:var(--text-light);width:32px;height:32px;border-radius:8px;display:flex;align-items:center;justify-content:center;transition:all .2s;line-height:1}
.modal-close:hover{background:#f1f5f9;color:var(--text)}
.modal-body{padding:22px 24px}
.modal-footer{padding:16px 24px;border-top:1px solid var(--border);display:flex;justify-content:flex-end;gap:10px;position:sticky;bottom:0;background:#fff;border-radius:0 0 16px 16px}

@keyframes slideUp{from{opacity:0;transform:translateY(24px)}to{opacity:1;transform:translateY(0)}}

/* 数据大屏 */
.dashboard{background:linear-gradient(160deg,#0f172a 0%,#1e293b 100%);border-radius:16px;padding:26px;color:#fff;min-height:300px}
.dashboard-title{font-size:22px;font-weight:800;text-align:center;margin-bottom:22px;background:linear-gradient(90deg,#60a5fa,#a78bfa,#f472b6);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;letter-spacing:1px}
.kpi-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:14px;margin-bottom:22px}
.kpi-card{background:rgba(255,255,255,.05);border:1px solid rgba(255,255,255,.1);border-radius:12px;padding:16px;text-align:center;backdrop-filter:blur(10px)}
.kpi-value{font-size:28px;font-weight:800;background:linear-gradient(90deg,#60a5fa,#a78bfa);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;line-height:1.2}
.kpi-label{font-size:12px;color:#94a3b8;margin-top:6px}
.kpi-hint{font-size:11px;color:#64748b;margin-top:3px}
.chart-grid{display:grid;grid-template-columns:repeat(12,1fr);gap:16px;margin-bottom:18px}
.chart-box{background:rgba(255,255,255,.04);border:1px solid rgba(255,255,255,.08);border-radius:12px;padding:14px}
.chart-box h4{font-size:13px;font-weight:600;color:#cbd5e1;margin-bottom:8px;padding-left:8px;border-left:3px solid #6366f1}
.insight-list{background:rgba(99,102,241,.1);border:1px solid rgba(99,102,241,.25);border-radius:12px;padding:16px 20px}
.insight-list h4{font-size:13px;color:#a5b4fc;margin-bottom:10px;font-weight:700}
.insight-list li{font-size:13px;color:#cbd5e1;margin-bottom:6px;list-style:none;padding-left:20px;position:relative}
.insight-list li::before{content:'▸';position:absolute;left:6px;color:#6366f1}

/* 进度条 */
.progress-bar{height:6px;background:#e2e8f0;border-radius:999px;overflow:hidden;margin-top:6px}
.progress-fill{height:100%;background:linear-gradient(90deg,#6366f1,#8b5cf6);border-radius:999px;transition:width .5s ease}

/* Toast */
#toast{position:fixed;top:20px;left:50%;transform:translateX(-50%) translateY(-100px);background:#1e293b;color:#fff;padding:12px 24px;border-radius:10px;font-size:14px;font-weight:600;z-index:9999;box-shadow:0 10px 30px rgba(0,0,0,.3);transition:transform .3s cubic-bezier(.34,1.56,.64,1);display:flex;align-items:center;gap:8px;max-width:calc(100vw - 40px)}
#toast.show{transform:translateX(-50%) translateY(0)}
#toast.success{background:#059669}
#toast.error{background:#dc2626}

/* Tabs */
.tabs{display:flex;gap:4px;border-bottom:1.5px solid var(--border);margin-bottom:20px;overflow-x:auto}
.tab{padding:10px 18px;border:none;background:none;font-size:14px;font-weight:600;color:var(--text-light);cursor:pointer;border-bottom:2.5px solid transparent;margin-bottom:-1.5px;transition:all .2s;font-family:inherit;white-space:nowrap}
.tab:hover{color:var(--text)}
.tab.active{color:var(--primary);border-bottom-color:var(--primary)}

/* 表格 */
.table-wrap{overflow-x:auto}
table{width:100%;border-collapse:collapse;font-size:13px}
th{text-align:left;padding:10px 12px;background:#f8fafc;font-weight:700;color:var(--text-light);font-size:12px;text-transform:uppercase;letter-spacing:.5px;border-bottom:1.5px solid var(--border);white-space:nowrap}
td{padding:12px;border-bottom:1px solid var(--border);vertical-align:middle}
tr:last-child td{border-bottom:none}
tr:hover td{background:#f8fafc}

/* 选项 */
.option-item{display:flex;align-items:center;gap:10px;padding:12px 14px;border:1.5px solid var(--border);border-radius:10px;margin-bottom:8px;cursor:pointer;transition:all .2s;font-size:14px;background:#fff}
.option-item:hover{border-color:#c7d2fe;background:#f8fafc}
.option-item.selected{border-color:var(--primary);background:var(--primary-light)}
.option-item input[type="radio"],.option-item input[type="checkbox"]{width:18px;height:18px;accent-color:var(--primary);cursor:pointer;flex-shrink:0}
.option-key{width:26px;height:26px;border-radius:7px;background:#f1f5f9;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;color:var(--text-light);flex-shrink:0}
.option-item.selected .option-key{background:var(--primary);color:#fff}

/* 上传区 */
.upload-zone{border:2px dashed var(--border);border-radius:10px;padding:22px;text-align:center;cursor:pointer;transition:all .2s;background:#f8fafc}
.upload-zone:hover{border-color:var(--primary);background:var(--primary-light)}
.upload-zone .icon{font-size:26px;margin-bottom:6px}
.upload-zone p{font-size:13px;color:var(--text-light)}

/* 工具类 */
.flex{display:flex}.items-center{align-items:center}.justify-between{justify-content:space-between}
.gap-2{gap:8px}.gap-3{gap:12px}.mt-2{margin-top:8px}.mt-3{margin-top:12px}.mb-2{margin-bottom:8px}.mb-3{margin-bottom:12px}
.text-sm{font-size:13px}.text-light{color:var(--text-light)}.font-bold{font-weight:700}.hidden{display:none!important}
.row-2{display:grid;grid-template-columns:1fr 1fr;gap:12px}

/* 班级块 */
.class-block{background:#fff;border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:16px;overflow:hidden}
.class-block-head{display:flex;align-items:center;justify-content:space-between;padding:16px 20px;background:linear-gradient(135deg,#f8fafc,#eef2ff);border-bottom:1px solid var(--border);flex-wrap:wrap;gap:10px}
.class-block-head .name{font-size:15px;font-weight:700;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.class-block-body .table-wrap{padding:0}
.class-block-body th{background:#fff}
.class-block-body td{padding:10px 12px}
.pwd-cell{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;color:var(--text-light)}
.import-tip{font-size:12px;color:var(--text-light);padding:12px 14px;background:#f8fafc;border-radius:10px;line-height:1.8}
.import-tip b{color:var(--text)}

/* 成长曲线 */
.growth-chart-wrap{width:100%;height:440px;background:#fff;border-radius:12px;padding:8px}
.growth-stat{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:12px;margin-bottom:18px}
.growth-stat-item{background:linear-gradient(135deg,#f8fafc,#eef2ff);border:1px solid var(--border);border-radius:12px;padding:14px 16px}
.growth-stat-item .label{font-size:12px;color:var(--text-light);margin-bottom:4px}
.growth-stat-item .value{font-size:22px;font-weight:800;background:linear-gradient(90deg,#6366f1,#8b5cf6);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}

/* AI 出题 */
.ai-header{background:linear-gradient(135deg,#8b5cf6,#ec4899);border-radius:12px;padding:16px 18px;color:#fff;margin-bottom:18px;display:flex;align-items:center;gap:12px}
.ai-header .ai-icon{font-size:28px}
.ai-header h4{font-size:15px;font-weight:700;margin-bottom:2px}
.ai-header p{font-size:12px;opacity:.9}
.ai-loading{text-align:center;padding:40px 20px}
.ai-loading .spinner{width:44px;height:44px;border:3px solid #e2e8f0;border-top-color:#8b5cf6;border-radius:50%;margin:0 auto 16px;animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.ai-step-list{text-align:left;max-width:320px;margin:0 auto}
.ai-step-list .st{font-size:13px;color:#94a3b8;padding:4px 0;transition:color .3s}
.ai-step-list .st.done{color:#059669}
.ai-step-list .st.active{color:#8b5cf6;font-weight:600}
.ai-preview-card{border:1.5px solid var(--border);border-radius:12px;padding:14px 16px;margin-bottom:10px;background:#fff;position:relative;transition:all .2s}
.ai-preview-card:hover{border-color:#c4b5fd;box-shadow:0 4px 14px rgba(139,92,246,.08)}
.ai-preview-card .pc-head{display:flex;align-items:flex-start;justify-content:space-between;gap:10px;margin-bottom:6px}
.ai-preview-card .pc-title{font-size:14px;font-weight:700;display:flex;align-items:center;gap:6px;flex-wrap:wrap}
.ai-preview-card .pc-desc{font-size:13px;color:var(--text-light);margin-bottom:8px}
.ai-preview-card .pc-options{display:flex;flex-wrap:wrap;gap:6px}
.ai-preview-card .pc-opt{font-size:12px;padding:3px 10px;border-radius:8px;background:#f8fafc;border:1px solid var(--border);color:var(--text-light)}
.ai-preview-card .pc-del{background:none;border:none;color:#cbd5e1;cursor:pointer;font-size:16px;line-height:1;padding:2px 6px;border-radius:6px;transition:all .2s}
.ai-preview-card .pc-del:hover{background:#fee2e2;color:#dc2626}

/* 链接框 */
.link-box{display:flex;gap:8px;align-items:center;margin-top:6px}
.link-box input{flex:1;padding:10px 12px;border:1.5px solid var(--border);border-radius:10px;font-size:13px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;background:#f8fafc;color:var(--text)}
.link-box input:focus{outline:none;border-color:var(--primary);background:#fff}
.qr-wrap{display:flex;justify-content:center;padding:14px;background:#f8fafc;border-radius:12px;margin-top:12px}
.qr-placeholder{width:140px;height:140px;background:#fff;border:1px solid var(--border);border-radius:10px;display:flex;align-items:center;justify-content:center;color:#cbd5e1;font-size:12px;text-align:center;padding:10px}

/* 登录页 */
.login-page{display:flex;align-items:center;justify-content:center;min-height:100vh;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);padding:20px}
.login-card{background:#fff;border-radius:20px;box-shadow:0 25px 60px rgba(0,0,0,.25);width:100%;max-width:420px;padding:40px 36px;animation:slideUp .5s ease}
.login-logo{text-align:center;margin-bottom:28px}
.login-logo .icon{width:64px;height:64px;border-radius:18px;background:linear-gradient(135deg,#6366f1,#8b5cf6);display:inline-flex;align-items:center;justify-content:center;font-size:30px;margin-bottom:14px;box-shadow:0 8px 20px rgba(99,102,241,.35)}
.login-logo h1{font-size:22px;font-weight:700}
.login-logo p{font-size:13px;color:var(--text-light);margin-top:4px}
.role-switch{display:flex;background:#f1f5f9;border-radius:10px;padding:4px;margin-bottom:22px}
.role-switch button{flex:1;border:none;background:transparent;padding:10px;border-radius:8px;font-size:14px;font-weight:600;color:var(--text-light);cursor:pointer;transition:all .2s;font-family:inherit}
.role-switch button.active{background:#fff;color:var(--primary);box-shadow:var(--shadow)}

/* 响应式 */
@media (max-width:600px){
  .row-2{grid-template-columns:1fr}
  .main{padding:18px 14px 60px}
  .topbar{padding:0 14px}
  .chart-grid{grid-template-columns:1fr!important}
  .chart-box{grid-column:span 12!important}
  .login-card{padding:30px 22px}
  .topbar-title{display:none}
  .growth-chart-wrap{height:360px}
}