:root{
  --primary:#1a56db;
  --primary-dark:#1e40af;
  --primary-light:#dbeafe;
  --bg:#f8fafc;
  --card:#fff;
  --text:#1e293b;
  --text-muted:#64748b;
  --border:#e2e8f0;
  --danger:#dc2626;
  --warning:#f59e0b;
  --success:#16a34a;
  --radius:10px;
  --shadow:0 1px 3px rgba(0,0,0,.08),0 1px 2px rgba(0,0,0,.06);
  --shadow-lg:0 4px 12px rgba(0,0,0,.1);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--text);line-height:1.6;min-height:100vh}
a{color:var(--primary);text-decoration:none}
.container{max-width:1100px;margin:0 auto;padding:0 16px}

/* ============ 顶部导航 ============ */
.top-bar{background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:100}
.top-bar-inner{display:flex;align-items:center;justify-content:space-between;height:56px}
.brand{font-size:18px;font-weight:700;color:var(--primary-dark)}
.main-nav{display:flex;gap:4px;flex-wrap:wrap}
.main-nav a{padding:6px 14px;border-radius:8px;font-size:14px;color:var(--text-muted);transition:all .15s}
.main-nav a:hover,.main-nav a.on{background:var(--primary-light);color:var(--primary-dark)}
.admin-link{font-size:12px!important;opacity:.6}
@media(max-width:600px){
  .top-bar-inner{flex-direction:column;height:auto;padding:8px 0}
  .main-nav{justify-content:center;margin-top:4px}
}

/* ============ 通用卡片 ============ */
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px;margin-bottom:16px}
.card h2{font-size:18px;margin-bottom:12px}
.btn{display:inline-block;padding:10px 24px;border-radius:8px;font-size:15px;font-weight:600;border:none;cursor:pointer;transition:all .15s}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-dark)}
.btn-outline{background:#fff;color:var(--primary);border:1px solid var(--primary)}
.btn-outline:hover{background:var(--primary-light)}
.btn-danger{background:var(--danger);color:#fff}
.btn-sm{padding:5px 14px;font-size:13px}

/* ============ 首页 ============ */
.hero{background:linear-gradient(135deg,#eff6ff 0%,#dbeafe 100%);padding:60px 16px;text-align:center}
.hero h1{font-size:32px;color:var(--primary-dark);margin-bottom:12px}
.hero p{color:var(--text-muted);max-width:600px;margin:0 auto 24px;font-size:16px}
.disclaimer-box{background:#fef3c7;border:1px solid #fbbf24;border-radius:var(--radius);padding:16px;margin:24px auto;max-width:600px;font-size:14px;color:#92400e}
.cat-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(160px,1fr));gap:16px;margin-top:20px}
.cat-item{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:20px 16px;text-align:center;cursor:pointer;transition:all .15s;box-shadow:var(--shadow)}
.cat-item:hover{border-color:var(--primary);box-shadow:var(--shadow-lg);transform:translateY(-2px)}
.cat-item .icon{font-size:36px;margin-bottom:8px}
.cat-item .name{font-size:15px;font-weight:600}

/* ============ 聊天页 ============ */
.chat-wrap{display:flex;flex-direction:column;height:calc(100vh - 56px - 60px);max-height:calc(100vh - 116px)}
.chat-area{flex:1;overflow-y:auto;padding:16px;scroll-behavior:smooth}
.msg-row{display:flex;margin-bottom:16px;animation:fadeUp .3s ease}
@keyframes fadeUp{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.msg-row.user{justify-content:flex-end}
.msg-row.assistant{justify-content:flex-start}
.bubble{max-width:78%;padding:12px 16px;border-radius:var(--radius);font-size:15px;white-space:pre-wrap;word-break:break-word;box-shadow:var(--shadow)}
.msg-row.user .bubble{background:var(--primary);color:#fff;border-bottom-right-radius:4px}
.msg-row.assistant .bubble{background:#fff;color:var(--text);border:1px solid var(--border);border-bottom-left-radius:4px}
.ai-note{font-size:12px;color:var(--text-muted);margin-top:6px;padding:4px 12px;background:#f1f5f9;border-radius:6px}
.chat-input-bar{display:flex;gap:8px;padding:12px 16px;background:#fff;border-top:1px solid var(--border);position:sticky;bottom:0}
.chat-input-bar textarea{flex:1;padding:10px 14px;border:1px solid var(--border);border-radius:8px;font-size:15px;resize:none;height:44px;min-height:44px;max-height:120px;transition:height .15s;font-family:inherit}
.chat-input-bar textarea:focus{border-color:var(--primary);outline:none}
.send-btn{width:44px;height:44px;border-radius:8px;background:var(--primary);color:#fff;border:none;cursor:pointer;font-size:20px;display:flex;align-items:center;justify-content:center;flex-shrink:0}
.send-btn:disabled{background:#94a3b8;cursor:not-allowed}
.chat-toolbar{display:flex;align-items:center;gap:12px;padding:8px 16px;background:#f8fafc;border-bottom:1px solid var(--border);flex-wrap:wrap}
.chip{padding:4px 12px;border-radius:20px;font-size:13px;border:1px solid var(--border);background:#fff;cursor:pointer;transition:all .15s;color:var(--text-muted)}
.chip:hover,.chip.on{border-color:var(--primary);color:var(--primary-dark);background:var(--primary-light)}
.loading-dots span{display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--primary);margin:0 3px;animation:bounce .6s infinite alternate}
.loading-dots span:nth-child(2){animation-delay:.2s}
.loading-dots span:nth-child(3){animation-delay:.4s}
@keyframes bounce{to{transform:translateY(-4px)}}
.session-bar{display:flex;justify-content:space-between;align-items:center;padding:8px 16px;background:#fff;border-bottom:1px solid var(--border);flex-wrap:wrap;gap:8px}
.session-bar .title{font-size:13px;color:var(--text-muted)}

/* ============ 历史页 ============ */
.session-item{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:16px;margin-bottom:12px;cursor:pointer;transition:all .15s;box-shadow:var(--shadow)}
.session-item:hover{border-color:var(--primary);box-shadow:var(--shadow-lg)}
.session-item h3{font-size:15px;margin-bottom:6px;color:var(--text)}
.session-item .meta{font-size:12px;color:var(--text-muted);display:flex;gap:16px}
.session-item .msgs-preview{font-size:13px;color:var(--text-muted);margin-top:8px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}

/* ============ 后台 ============ */
.admin-layout{display:flex;min-height:100vh}
.admin-sidebar{width:220px;background:#1e293b;color:#fff;padding:20px 0;flex-shrink:0}
.admin-sidebar .logo{padding:0 20px 20px;font-size:16px;font-weight:700;border-bottom:1px solid #334155;margin-bottom:16px}
.admin-sidebar a{display:block;padding:10px 20px;color:#94a3b8;font-size:14px;transition:all .15s}
.admin-sidebar a:hover,.admin-sidebar a.on{background:#334155;color:#fff;border-left:3px solid var(--primary)}
.admin-main{flex:1;padding:24px;overflow-x:auto;min-width:0}
.admin-main h1{font-size:22px;margin-bottom:20px}
.form-group{margin-bottom:16px}
.form-group label{display:block;font-size:13px;font-weight:600;color:var(--text-muted);margin-bottom:6px}
.form-group input,.form-group textarea,.form-group select{width:100%;padding:10px 14px;border:1px solid var(--border);border-radius:8px;font-size:14px;font-family:inherit}
.form-group input:focus,.form-group textarea:focus{border-color:var(--primary);outline:none}
.form-group textarea{min-height:120px;resize:vertical}
.table-wrap{overflow-x:auto}
table.data-table{width:100%;border-collapse:collapse;font-size:14px}
table.data-table th{background:#f8fafc;padding:10px 12px;text-align:left;border-bottom:2px solid var(--border);font-weight:600;font-size:13px;color:var(--text-muted)}
table.data-table td{padding:10px 12px;border-bottom:1px solid var(--border);vertical-align:top}
table.data-table tr:hover td{background:#f8fafc}
.badge{display:inline-block;padding:2px 8px;border-radius:4px;font-size:12px;font-weight:600}
.badge-danger{background:#fef2f2;color:var(--danger)}
.badge-success{background:#f0fdf4;color:var(--success)}
.badge-warn{background:#fefce8;color:#92400e}
.stat-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:16px;margin-bottom:24px}
.stat-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow)}
.stat-card .num{font-size:28px;font-weight:700;color:var(--primary)}
.stat-card .label{font-size:13px;color:var(--text-muted);margin-top:4px}
.bar-row{display:flex;align-items:center;gap:8px;margin-bottom:8px}
.bar-label{width:80px;font-size:13px;color:var(--text-muted);text-align:right;flex-shrink:0}
.bar-track{flex:1;height:20px;background:#f1f5f9;border-radius:4px;overflow:hidden}
.bar-fill{height:100%;background:var(--primary);border-radius:4px;min-width:2px;transition:width .3s}
.bar-val{width:40px;font-size:12px;color:var(--text-muted)}

/* ============ 登录页 ============ */
.login-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:16px}
.login-card{background:#fff;border-radius:12px;box-shadow:var(--shadow-lg);padding:40px;width:100%;max-width:380px}
.login-card h1{font-size:22px;text-align:center;margin-bottom:24px;color:var(--primary-dark)}

/* ============ 通用响应式 ============ */
@media(max-width:768px){
  .admin-layout{flex-direction:column}
  .admin-sidebar{width:100%;padding:0}
  .admin-sidebar a{display:inline-block;padding:8px 16px}
  .admin-main{padding:16px}
  .bubble{max-width:90%}
  .hero{padding:40px 16px}
  .hero h1{font-size:24px}
}

/* ============ 文件上传 ============ */
.upload-area{border:2px dashed var(--border);border-radius:var(--radius);padding:20px;text-align:center;color:var(--text-muted);cursor:pointer;transition:all .15s}
.upload-area:hover,.upload-area.drag{border-color:var(--primary);background:var(--primary-light)}
.upload-area .icon{font-size:32px;margin-bottom:8px}
.img-preview{display:flex;gap:8px;flex-wrap:wrap;margin-top:8px}
.img-preview img{width:60px;height:60px;object-fit:cover;border-radius:6px;border:2px solid var(--border)}
.img-remove{position:relative;width:60px;height:60px}
.img-remove .del{position:absolute;top:-4px;right:-4px;width:20px;height:20px;background:var(--danger);color:#fff;border-radius:50%;font-size:12px;display:flex;align-items:center;justify-content:center;cursor:pointer;border:none}

/* ============ Toast ============ */
.toast{position:fixed;top:70px;left:50%;transform:translateX(-50%);padding:10px 24px;border-radius:8px;font-size:14px;z-index:9999;opacity:0;transition:opacity .2s;pointer-events:none;background:#1e293b;color:#fff}
.toast.show{opacity:1}
.toast.error{background:var(--danger)}
.toast.success{background:var(--success)}

/* ============ Modal ============ */
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.5);z-index:200;display:flex;align-items:center;justify-content:center;padding:16px}
.modal{background:#fff;border-radius:12px;padding:24px;max-width:560px;width:100%;max-height:90vh;overflow-y:auto}
.modal h3{margin-bottom:16px}
.msg-detail{background:#f8fafc;border-radius:8px;padding:16px;max-height:400px;overflow-y:auto;font-size:14px}