:root{
  --bg:#f6f8fc;
  --surface:#ffffff;
  --surface-soft:#f8fafc;
  --text:#0f172a;
  --muted:#64748b;
  --line:#e2e8f0;
  --primary:#2563eb;
  --primary-2:#06b6d4;
  --primary-3:#7c3aed;
  --success:#16a34a;
  --danger:#ef4444;
  --warning:#f59e0b;
  --shadow:0 22px 70px rgba(15,23,42,.09);
  --shadow-soft:0 10px 34px rgba(15,23,42,.07);
  --radius:24px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  min-height:100vh;
  font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;
  color:var(--text);
  background:
    radial-gradient(circle at 8% -4%,rgba(37,99,235,.16),transparent 34%),
    radial-gradient(circle at 92% 0%,rgba(6,182,212,.16),transparent 30%),
    linear-gradient(180deg,#fff 0%,#f8fafc 48%,#eef4ff 100%);
}
body:before{
  content:"";
  position:fixed;
  inset:0;
  pointer-events:none;
  background-image:linear-gradient(rgba(15,23,42,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(15,23,42,.035) 1px,transparent 1px);
  background-size:42px 42px;
  mask-image:linear-gradient(to bottom,black,transparent 82%);
}
a{color:inherit;text-decoration:none}
img,svg{max-width:100%}
button,input,textarea,select{font:inherit}
.container{width:min(1180px,92%);margin:0 auto;position:relative}

/* Shared surfaces */
.glass,.feature,.card,.chat-card,.auth-card,.panel{
  background:rgba(255,255,255,.88);
  border:1px solid rgba(226,232,240,.95);
  box-shadow:var(--shadow);
  backdrop-filter:blur(18px);
  border-radius:var(--radius);
}
.feature,.card{padding:24px}
.feature h2,.feature h3,.card h2,.card h3{margin-top:0;letter-spacing:-.45px}
.feature p,.card p{color:var(--muted);line-height:1.7}
.muted{color:var(--muted)}

/* Logo */
.logo{display:inline-flex;align-items:center;gap:12px;font-weight:950;letter-spacing:-.4px;color:var(--text);min-width:0}
.logo i{
  flex:0 0 auto;
  width:46px;height:46px;border-radius:16px;display:grid;place-items:center;
  background:linear-gradient(135deg,var(--primary),var(--primary-2));
  color:#fff;font-style:normal;font-weight:950;box-shadow:0 16px 36px rgba(37,99,235,.25)
}
.logo span{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}

/* Buttons / pills */
.btn,button{
  appearance:none;border:0;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:46px;padding:13px 18px;border-radius:15px;color:#fff;font-weight:850;
  background:linear-gradient(135deg,var(--primary),var(--primary-2));
  box-shadow:0 14px 30px rgba(37,99,235,.24);transition:transform .2s ease,box-shadow .2s ease,opacity .2s ease;
  white-space:nowrap;
}
.btn:hover,button:hover{transform:translateY(-2px);box-shadow:0 20px 44px rgba(37,99,235,.3)}
.btn.secondary{background:#fff;color:#1d4ed8;border:1px solid #bfdbfe;box-shadow:var(--shadow-soft)}
.btn.danger,.btn-danger{background:linear-gradient(135deg,#ef4444,#f97316)}
.pill{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:10px 14px;border-radius:999px;
  border:1px solid #bfdbfe;background:#eff6ff;color:#1d4ed8;font-weight:850;line-height:1.2
}

/* Forms */
.form{display:grid;gap:14px}
.input,input,textarea,select{
  width:100%;border:1px solid var(--line);background:#fff;color:var(--text);border-radius:16px;
  padding:13px 15px;outline:none;transition:border-color .2s ease,box-shadow .2s ease;font-size:15px;
}
textarea{min-height:124px;resize:vertical;line-height:1.55}
.input::placeholder,input::placeholder,textarea::placeholder{color:#94a3b8}
.input:focus,input:focus,textarea:focus,select:focus{border-color:var(--primary);box-shadow:0 0 0 4px rgba(37,99,235,.12)}
.split{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}
.notice{padding:13px 15px;border-radius:16px;margin:12px 0;background:#eff6ff;border:1px solid #bfdbfe;color:#1d4ed8;font-weight:750}
.notice.danger,.danger{background:#fef2f2!important;border-color:#fecaca!important;color:#b91c1c!important}
.notice.success{background:#f0fdf4;border-color:#bbf7d0;color:#15803d}

/* Public header */
.nav{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:22px 0;position:relative;z-index:5}
.nav .actions{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-top:0}
.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}

/* Public landing */
.hero{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(330px,.95fr);gap:34px;align-items:center;padding:42px 0 68px}
.hero h1{font-size:clamp(42px,6vw,78px);line-height:.96;margin:18px 0;letter-spacing:-3.2px;color:#07111f}
.hero h1 span,.gradient-text{background:linear-gradient(135deg,var(--primary),var(--primary-2),var(--primary-3));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p{font-size:18px;line-height:1.75;color:var(--muted);max-width:700px;margin:0}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;padding:20px 0 70px}
.feature{position:relative;overflow:hidden}
.feature:after{content:"";position:absolute;inset:auto -40px -60px auto;width:160px;height:160px;border-radius:999px;background:rgba(37,99,235,.08);pointer-events:none}

/* Chat */
.chat-card{padding:18px;overflow:hidden}
.chat-head{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:8px 8px 16px;color:#334155}
.dots{display:flex;gap:7px;flex:0 0 auto}.dots span{width:11px;height:11px;border-radius:99px;background:#ff5f57}.dots span:nth-child(2){background:#febc2e}.dots span:nth-child(3){background:#28c840}
.chat-box{height:430px;overflow:auto;padding:16px;border-radius:22px;background:#f8fafc;border:1px solid var(--line);scrollbar-width:thin}
.msg{display:flex;margin:12px 0}.msg.user{justify-content:flex-end}.msg.bot{justify-content:flex-start}
.bubble{max-width:84%;padding:13px 15px;border-radius:18px;line-height:1.58;color:#334155;background:#fff;border:1px solid var(--line);white-space:pre-wrap;word-break:break-word;box-shadow:0 8px 24px rgba(15,23,42,.05)}
.user .bubble{background:linear-gradient(135deg,var(--primary),var(--primary-2));border-color:transparent;color:#fff}
.chat-form{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:10px;margin-top:12px}

/* Auth */
.auth-body{min-height:100vh;display:grid;place-items:center;padding:24px}
.auth-card{width:min(460px,94vw);padding:34px}.auth-card h1{font-size:34px;letter-spacing:-1px;margin:26px 0 8px}.auth-card p{margin-top:0;line-height:1.6}

/* Admin layout */
.admin-wrap{display:grid;grid-template-columns:280px minmax(0,1fr);min-height:100vh;position:relative}
.side{position:sticky;top:0;height:100vh;padding:24px;background:rgba(255,255,255,.92);border-right:1px solid var(--line);backdrop-filter:blur(18px);overflow:auto;z-index:10}
.side .logo{margin-bottom:28px}.side nav{display:grid;gap:8px}
.side a{display:flex;align-items:center;gap:10px;padding:12px 14px;border-radius:15px;color:#475569;font-weight:820;transition:.18s ease;white-space:nowrap}
.side a:hover,.side a.active{background:#eff6ff;color:#1d4ed8}
.main{min-width:0;padding:28px;position:relative;z-index:1}
.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:22px}
.topbar h1{font-size:32px;line-height:1.1;margin:0;letter-spacing:-1px}.topbar .pill{flex:0 0 auto}
.cards{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;margin-bottom:18px}
.card b{display:block;font-size:30px;margin-top:6px;line-height:1.1;color:#0f172a}.card span{font-weight:800}

/* Tables */
.table-wrap{width:100%;overflow:auto;border-radius:20px;border:1px solid var(--line);background:#fff;box-shadow:var(--shadow-soft)}
.table{width:100%;min-width:760px;border-collapse:collapse;background:#fff;overflow:hidden;border-radius:0}
.table th,.table td{padding:15px 16px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top;color:#334155;line-height:1.45}
.table th{background:#f8fafc;color:#475569;font-size:12px;text-transform:uppercase;letter-spacing:.55px;white-space:nowrap;font-weight:900}
.table tr:hover td{background:#fbfdff}.table a{color:#1d4ed8;font-weight:800}.table small{line-height:1.5}.table td:last-child{white-space:nowrap}

/* Small helpers */
hr{border:0;border-top:1px solid var(--line);margin:20px 0}
small{font-size:12px}.w-auto{width:auto!important}

@media(max-width:1080px){
  .hero{grid-template-columns:1fr}.grid{grid-template-columns:repeat(2,minmax(0,1fr))}.cards{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:820px){
  .container{width:min(94%,1180px)}
  .nav{align-items:flex-start;flex-direction:column;padding:16px 0}.nav .actions{width:100%;overflow:auto;flex-wrap:nowrap;padding-bottom:2px}.nav .actions .pill,.nav .actions .btn{flex:0 0 auto}
  .hero{padding:34px 0 42px;gap:22px}.hero h1{font-size:42px;letter-spacing:-2px}.hero p{font-size:16px}.grid,.split{grid-template-columns:1fr}.grid{padding-bottom:42px}
  .chat-box{height:360px}.chat-form{grid-template-columns:1fr}.chat-form .btn,.chat-form button{width:100%}.bubble{max-width:92%}
  .admin-wrap{display:block}.side{position:relative;height:auto;border-right:0;border-bottom:1px solid var(--line);padding:16px}.side .logo{margin-bottom:14px}.side nav{display:flex;gap:8px;overflow:auto;padding-bottom:4px}.side nav a{flex:0 0 auto}
  .main{padding:16px}.topbar{align-items:flex-start;flex-direction:column}.topbar h1{font-size:27px}.topbar .pill{width:100%}.cards{grid-template-columns:1fr}
  .feature,.card,.chat-card{padding:18px;border-radius:20px}.auth-card{padding:24px}.auth-card h1{font-size:29px}
}
@media(max-width:520px){
  .logo i{width:42px;height:42px}.logo span{font-size:16px}.btn,button{width:100%;white-space:normal}.actions{flex-direction:column}.actions .btn,.actions .pill{width:100%}
  .hero h1{font-size:38px}.pill{width:100%}.chat-head{align-items:flex-start;flex-direction:column}.table{min-width:720px}
}
input[type="hidden"]{
  display:none !important;
}

.editor-toolbar{
  display:flex;
  gap:8px;
  flex-wrap:wrap;
  margin:10px 0;
}

.editor-toolbar button{
  width:auto;
  padding:10px 16px;
}

.rich-editor{
  min-height:180px;
  border:1px solid #dbe3ef;
  border-radius:16px;
  padding:14px;
  background:#fff;
  outline:none;
  line-height:1.6;
}

.rich-editor:focus{
  border-color:#168fe3;
  box-shadow:0 0 0 3px rgba(22,143,227,.12);
}
.rich-editor{
  display:block !important;
  min-height:180px !important;
  width:100% !important;
  border:1px solid #dbe3ef !important;
  border-radius:16px !important;
  padding:14px !important;
  background:#fff !important;
  outline:none !important;
  line-height:1.6 !important;
  color:#0f172a !important;
  margin-bottom:16px !important;
}

.rich-editor:empty:before{
  content:"Nhập nội dung knowledge...";
  color:#94a3b8;
}

.rich-editor:focus{
  border-color:#168fe3 !important;
  box-shadow:0 0 0 3px rgba(22,143,227,.12) !important;
}
.bubble b,
.bubble strong{
  font-weight:700;
}

.bubble i,
.bubble em{
  font-style:italic;
}

.bubble ul{
  padding-left:20px;
  margin-top:8px;
}

.bubble li{
  margin-bottom:6px;
}

/* ===== Rich Knowledge Editor ===== */
input[type="hidden"]{display:none !important;}
.editor-toolbar{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0 12px;}
.editor-toolbar button{width:auto !important;padding:10px 16px !important;border-radius:12px;}
.rich-editor{display:block !important;min-height:180px !important;width:100% !important;box-sizing:border-box !important;border:1px solid #dbe3ef !important;border-radius:16px !important;padding:14px !important;background:#fff !important;outline:none !important;line-height:1.6 !important;color:#0f172a !important;margin-bottom:16px !important;}
.rich-editor:empty:before{content:"Nhập nội dung knowledge...";color:#94a3b8;}
.rich-editor:focus{border-color:#168fe3 !important;box-shadow:0 0 0 3px rgba(22,143,227,.12) !important;}
.rich-editor ul,.rich-editor ol{padding-left:22px;margin:8px 0;}
.rich-editor li{margin:4px 0;}
.bubble b,.bubble strong{font-weight:700;}
.bubble i,.bubble em{font-style:italic;}
.bubble ul,.bubble ol{padding-left:20px;margin:8px 0;}
.bubble li{margin-bottom:6px;}
.bubble pre{font-family:inherit;font-size:14px;}

/* =========================
   Admin AI UI Optimized 2026
   ========================= */
body.admin-body{
  background:
    radial-gradient(circle at 0% 0%, rgba(37,99,235,.18), transparent 34%),
    radial-gradient(circle at 100% 10%, rgba(124,58,237,.13), transparent 30%),
    linear-gradient(135deg,#f8fbff 0%,#eef4ff 48%,#f8fafc 100%);
}
.admin-shell{display:grid;grid-template-columns:292px minmax(0,1fr);min-height:100vh;position:relative;z-index:1}
.admin-sidebar{position:sticky;top:0;height:100vh;padding:22px;background:rgba(255,255,255,.82);border-right:1px solid rgba(226,232,240,.9);backdrop-filter:blur(24px);overflow:auto;z-index:20}
.admin-brand{display:flex;align-items:center;gap:12px;margin-bottom:22px;padding:10px;border-radius:20px;color:#0f172a}
.admin-brand i{width:48px;height:48px;border-radius:18px;display:grid;place-items:center;background:linear-gradient(135deg,#2563eb,#06b6d4);color:#fff;font-weight:950;font-style:normal;box-shadow:0 16px 38px rgba(37,99,235,.28)}
.admin-brand span{display:grid;line-height:1.15}.admin-brand small{color:#64748b;font-size:12px;font-weight:800}.admin-brand b{font-size:15px;letter-spacing:-.2px}
.admin-nav{display:grid;gap:8px}.admin-nav a{display:flex;align-items:center;gap:11px;padding:12px 13px;border-radius:16px;color:#475569;font-weight:850;transition:.18s ease;border:1px solid transparent}.admin-nav a em{font-style:normal;width:28px;height:28px;display:grid;place-items:center;border-radius:11px;background:#f1f5f9}.admin-nav a:hover,.admin-nav a.active{background:#eff6ff;color:#1d4ed8;border-color:#bfdbfe;transform:translateX(2px)}.admin-nav a.active em{background:#dbeafe}
.admin-side-card{margin:22px 0;padding:16px;border-radius:20px;background:linear-gradient(135deg,#eff6ff,#eef2ff);border:1px solid #bfdbfe;color:#1e3a8a}.admin-side-card p{margin:6px 0 0;color:#475569;font-size:13px;line-height:1.5}.admin-logout{display:flex;align-items:center;justify-content:center;margin-top:12px;padding:12px;border-radius:15px;background:#fff;border:1px solid #fecaca;color:#b91c1c;font-weight:900}
.admin-main{min-width:0;padding:28px}.admin-topbar{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:22px}.admin-topbar h1{font-size:34px;line-height:1;margin:0 0 8px;letter-spacing:-1.3px}.admin-eyebrow{margin:0 0 8px;color:#2563eb;font-size:12px;font-weight:950;text-transform:uppercase;letter-spacing:.14em}.admin-top-actions{display:flex;gap:10px;flex-wrap:wrap}
.admin-panel{background:rgba(255,255,255,.88);border:1px solid rgba(226,232,240,.96);box-shadow:0 18px 55px rgba(15,23,42,.08);backdrop-filter:blur(18px);border-radius:26px;padding:22px;overflow:hidden}.panel-head{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;margin-bottom:18px}.panel-head h2{margin:0 0 6px;font-size:22px;letter-spacing:-.6px}.panel-head a{color:#2563eb;font-weight:900}.count-pill{display:inline-flex;align-items:center;white-space:nowrap;border-radius:999px;background:#f1f5f9;border:1px solid #e2e8f0;padding:8px 12px;color:#334155;font-weight:900;font-size:12px}
.admin-stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin-bottom:18px}.stat-card{position:relative;overflow:hidden;background:rgba(255,255,255,.9);border:1px solid #e2e8f0;border-radius:24px;padding:20px;box-shadow:0 16px 45px rgba(15,23,42,.07)}.stat-card:after{content:"";position:absolute;right:-42px;bottom:-48px;width:130px;height:130px;border-radius:999px;background:rgba(37,99,235,.08)}.stat-card span{display:block;color:#64748b;font-weight:900}.stat-card b{display:block;margin:8px 0 5px;font-size:34px;letter-spacing:-1.2px;color:#0f172a;line-height:1}.stat-card small{color:#64748b;font-weight:750}
.admin-grid-2,.settings-layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(360px,.82fr);gap:18px;margin-bottom:18px}.quick-actions{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.quick-card{display:block;padding:16px;border-radius:20px;background:#f8fafc;border:1px solid #e2e8f0;transition:.18s ease}.quick-card:hover{transform:translateY(-2px);box-shadow:0 14px 32px rgba(15,23,42,.08);border-color:#bfdbfe;background:#eff6ff}.quick-card b{display:block;color:#0f172a;margin-bottom:5px}.quick-card small,.mini-item small{color:#64748b;line-height:1.5}.admin-steps{margin:0;padding-left:22px;color:#334155;line-height:1.85}.admin-steps li{margin:6px 0}.mini-list{display:grid;gap:10px}.mini-item{padding:13px 14px;border-radius:17px;background:#f8fafc;border:1px solid #e2e8f0}.mini-item b{display:block;margin-bottom:5px;color:#0f172a;line-height:1.4}
.knowledge-layout{display:grid;grid-template-columns:minmax(380px,.72fr) minmax(0,1.28fr);gap:18px;align-items:start}.knowledge-form{position:sticky;top:22px}.field-label{display:block;margin:4px 0 8px;color:#334155;font-size:13px;font-weight:950}.form-row{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:end;gap:12px}.btn-save{min-width:170px}.admin-search-box{margin-bottom:14px}.admin-table-wrap{border-radius:22px;max-height:680px}.admin-table thead th{position:sticky;top:0;z-index:3}.admin-table td{font-size:14px}.status-badge{display:inline-flex;align-items:center;border-radius:999px;padding:7px 10px;font-weight:900;font-size:12px;background:#f1f5f9;color:#475569;border:1px solid #e2e8f0}.status-badge.ok{background:#f0fdf4;color:#15803d;border-color:#bbf7d0}.status-badge.off{background:#f8fafc;color:#64748b}.action-links{display:flex;gap:10px;align-items:center}.action-links a{display:inline-flex;padding:8px 10px;border-radius:12px;background:#eff6ff;color:#1d4ed8;font-weight:950}.action-links .danger-link{background:#fef2f2;color:#b91c1c}
.editor-toolbar{display:flex!important;gap:8px!important;flex-wrap:wrap!important;margin:4px 0 10px!important}.editor-toolbar button{width:auto!important;min-height:38px!important;padding:8px 12px!important;border-radius:12px!important;background:#fff!important;color:#1e293b!important;border:1px solid #cbd5e1!important;box-shadow:none!important}.editor-toolbar button:hover{background:#eff6ff!important;color:#1d4ed8!important;transform:translateY(-1px)!important}.rich-editor{display:block!important;min-height:220px!important;width:100%!important;border:1px solid #dbe3ef!important;border-radius:18px!important;padding:15px!important;background:#fff!important;outline:none!important;line-height:1.7!important;color:#0f172a!important;margin-bottom:16px!important;box-shadow:inset 0 1px 0 rgba(15,23,42,.02)!important;overflow:auto!important}.rich-editor:empty:before{content:"Nhập nội dung knowledge / note tại đây...";color:#94a3b8}.rich-editor:focus{border-color:#2563eb!important;box-shadow:0 0 0 4px rgba(37,99,235,.12)!important}.rich-editor ul,.rich-editor ol{padding-left:22px}.rich-editor li{margin:4px 0}input[type="hidden"]{display:none!important}
.upload-drop{display:grid;place-items:center;text-align:center;min-height:190px;border:2px dashed #bfdbfe;border-radius:24px;background:linear-gradient(135deg,#eff6ff,#f8fafc);cursor:pointer;padding:24px;color:#1e3a8a}.upload-drop input{display:none}.upload-drop b{font-size:20px;margin-bottom:6px}.upload-drop small{color:#64748b;font-weight:800}.admin-login-bg{background:radial-gradient(circle at 0 0,rgba(37,99,235,.2),transparent 35%),linear-gradient(135deg,#f8fafc,#eef4ff)}.admin-login-card{border-radius:28px;box-shadow:0 24px 80px rgba(15,23,42,.12)}
.bubble b,.bubble strong{font-weight:800}.bubble i,.bubble em{font-style:italic}.bubble ul,.bubble ol{padding-left:22px;margin:8px 0}.bubble li{margin-bottom:6px}.bubble pre{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:12px;line-height:1.55;background:#0f172a;color:#e2e8f0;border-radius:14px;padding:12px;overflow:auto}
@media(max-width:1180px){.admin-stats{grid-template-columns:repeat(2,minmax(0,1fr))}.knowledge-layout,.admin-grid-2,.settings-layout{grid-template-columns:1fr}.knowledge-form{position:relative;top:0}}
@media(max-width:860px){.admin-shell{display:block}.admin-sidebar{position:relative;height:auto;border-right:0;border-bottom:1px solid #e2e8f0}.admin-nav{display:flex;overflow:auto;padding-bottom:4px}.admin-nav a{flex:0 0 auto}.admin-side-card,.admin-logout{display:none}.admin-main{padding:16px}.admin-topbar{display:block}.admin-stats{grid-template-columns:1fr}.quick-actions{grid-template-columns:1fr}.form-row{grid-template-columns:1fr}.btn-save{width:100%}.admin-panel{padding:18px;border-radius:22px}.admin-table{min-width:780px}}