:root{--bg: #f8fafc;--card: #ffffff;--text: #0f172a;--muted: #64748b;--primary: #4f46e5;--border: #e2e8f0;--danger: #dc2626;--success: #16a34a}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text);line-height:1.6}a{color:var(--primary);text-decoration:none}.container{max-width:1100px;margin:0 auto;padding:0 16px}.nav{background:var(--card);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:50}.nav-inner{max-width:1100px;margin:0 auto;padding:12px 16px;display:flex;align-items:center;gap:16px;flex-wrap:wrap}.nav a{color:var(--text);font-weight:500}.nav .brand{font-weight:700;color:var(--primary);font-size:1.1rem}.nav .spacer{flex:1}.btn{display:inline-flex;align-items:center;gap:6px;background:var(--primary);color:#fff!important;border:none;border-radius:10px;padding:8px 16px;cursor:pointer;font-size:14px;font-weight:500}.btn:hover{opacity:.9}.btn.secondary{background:var(--card);color:var(--text)!important;border:1px solid var(--border)}.btn.danger{background:var(--danger)}.btn:disabled{opacity:.5;cursor:not-allowed}.card{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:20px}.grid{display:grid;gap:16px}.grid.cols-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}.grid.cols-3{grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}.grid.cols-4{grid-template-columns:repeat(auto-fit,minmax(180px,1fr))}.input,select,textarea{width:100%;border:1px solid var(--border);border-radius:10px;padding:10px 12px;font-size:14px;background:var(--card)}textarea{min-height:120px;resize:vertical}label{display:block;font-size:14px;font-weight:500;margin-bottom:6px}.field{margin-bottom:14px}.muted{color:var(--muted);font-size:14px}.error{background:#fef2f2;color:var(--danger);border:1px solid #fecaca;border-radius:10px;padding:10px 12px;margin-bottom:12px;font-size:14px}.success{background:#f0fdf4;color:var(--success);border:1px solid #bbf7d0;border-radius:10px;padding:10px 12px;margin-bottom:12px;font-size:14px}.hero{padding:64px 0 40px;text-align:center}.hero h1{font-size:2.4rem;margin:0 0 12px}.hero p{color:var(--muted);font-size:1.05rem;max-width:640px;margin:0 auto 24px}.footer{margin-top:48px;padding:24px;text-align:center;color:var(--muted);border-top:1px solid var(--border);font-size:14px}.chat-layout{display:grid;grid-template-columns:280px 1fr;gap:16px;min-height:70vh}.chat-list{max-height:70vh;overflow:auto}.chat-item{padding:12px;border-radius:12px;cursor:pointer;border:1px solid transparent}.chat-item:hover,.chat-item.active{background:#eef2ff;border-color:#c7d2fe}.msg{max-width:70%;padding:10px 14px;border-radius:14px;margin:6px 0;background:#e2e8f0}.msg.mine{margin-left:auto;background:#e0e7ff}.admin-layout{display:grid;grid-template-columns:200px 1fr;gap:20px;padding:20px 0}.admin-nav a{display:block;padding:10px 12px;border-radius:10px;color:var(--text);margin-bottom:4px}.admin-nav a.active,.admin-nav a:hover{background:#eef2ff;color:var(--primary)}table{width:100%;border-collapse:collapse;font-size:14px}th,td{text-align:left;padding:10px 8px;border-bottom:1px solid var(--border)}.badge{display:inline-block;padding:2px 8px;border-radius:999px;font-size:12px;background:#eef2ff;color:var(--primary)}@media(max-width:768px){.chat-layout,.admin-layout{grid-template-columns:1fr}}