/* ============================================================
   BillFlow — Design System (light, clean, professional)
   ============================================================ */
:root{
  /* Brand */
  --brand:#2563eb; --brand-600:#2563eb; --brand-700:#1d4ed8; --brand-50:#eff6ff;
  --brand-100:#dbeafe;
  /* Semantic */
  --success:#059669; --success-50:#ecfdf5;
  --warning:#d97706; --warning-50:#fffbeb;
  --danger:#dc2626;  --danger-50:#fef2f2;
  /* Surfaces */
  --bg:#f1f5f9; --surface:#ffffff; --surface-2:#f8fafc;
  --border:#e2e8f0; --border-strong:#cbd5e1;
  /* Text */
  --text:#0f172a; --text-2:#475569; --text-3:#94a3b8;
  /* Effects */
  --radius:12px; --radius-sm:8px; --radius-lg:16px;
  --shadow-sm:0 1px 2px rgba(15,23,42,.06);
  --shadow:0 1px 3px rgba(15,23,42,.08),0 1px 2px rgba(15,23,42,.04);
  --shadow-md:0 4px 12px rgba(15,23,42,.08);
  --shadow-lg:0 12px 32px rgba(15,23,42,.12);
  --sidebar-w:248px;
  --font:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px}
body{font-family:var(--font);background:var(--bg);color:var(--text);
  line-height:1.5;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none;background:none}
input,select,textarea{font-family:inherit;font-size:1rem}
.tabular{font-variant-numeric:tabular-nums}

/* ---------- Layout ---------- */
.app{display:flex;min-height:100dvh}
.sidebar{width:var(--sidebar-w);background:var(--surface);border-right:1px solid var(--border);
  position:fixed;top:0;left:0;height:100dvh;display:flex;flex-direction:column;z-index:40}
.main{margin-left:var(--sidebar-w);flex:1;min-width:0;display:flex;flex-direction:column}
.content{padding:28px 32px;max-width:1400px;width:100%;margin:0 auto}

/* ---------- Brand / Sidebar ---------- */
.brand{display:flex;align-items:center;gap:10px;padding:20px 20px;border-bottom:1px solid var(--border)}
.brand-mark{width:34px;height:34px;border-radius:9px;background:linear-gradient(135deg,var(--brand),#4f46e5);
  display:grid;place-items:center;color:#fff;flex-shrink:0}
.brand-name{font-weight:700;font-size:1.15rem;letter-spacing:-.02em}
.nav{padding:12px 12px;flex:1;overflow-y:auto}
.nav-label{font-size:.7rem;font-weight:600;text-transform:uppercase;letter-spacing:.06em;
  color:var(--text-3);padding:14px 12px 6px}
.nav-item{display:flex;align-items:center;gap:11px;padding:10px 12px;border-radius:var(--radius-sm);
  color:var(--text-2);font-weight:500;font-size:.925rem;transition:background .15s,color .15s;margin-bottom:2px}
.nav-item svg{width:19px;height:19px;flex-shrink:0}
.nav-item:hover{background:var(--surface-2);color:var(--text)}
.nav-item.active{background:var(--brand-50);color:var(--brand-700);font-weight:600}
.nav-foot{padding:14px;border-top:1px solid var(--border)}
.user-chip{display:flex;align-items:center;gap:10px;padding:8px;border-radius:var(--radius-sm)}
.avatar{width:34px;height:34px;border-radius:50%;background:var(--brand-100);color:var(--brand-700);
  display:grid;place-items:center;font-weight:600;font-size:.85rem}

/* ---------- Topbar ---------- */
.topbar{height:64px;background:var(--surface);border-bottom:1px solid var(--border);
  display:flex;align-items:center;justify-content:space-between;padding:0 32px;position:sticky;top:0;z-index:30}
.topbar h1{font-size:1.25rem;font-weight:700;letter-spacing:-.02em}
.topbar .sub{color:var(--text-3);font-size:.85rem;font-weight:500}
.menu-btn{display:none}

/* ---------- Cards ---------- */
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-sm)}
.card-pad{padding:20px}
.card-head{display:flex;align-items:center;justify-content:space-between;padding:18px 20px;border-bottom:1px solid var(--border)}
.card-head h3{font-size:1rem;font-weight:650}
.grid{display:grid;gap:18px}
.grid-4{grid-template-columns:repeat(4,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}

/* ---------- Stat cards ---------- */
.stat{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:20px;box-shadow:var(--shadow-sm);position:relative;overflow:hidden}
.stat-ico{width:42px;height:42px;border-radius:11px;display:grid;place-items:center;margin-bottom:14px}
.stat-ico svg{width:21px;height:21px}
.stat-label{color:var(--text-2);font-size:.82rem;font-weight:550;margin-bottom:4px}
.stat-value{font-size:1.7rem;font-weight:750;letter-spacing:-.02em}
.stat-sub{font-size:.78rem;color:var(--text-3);margin-top:4px}
.ico-blue{background:var(--brand-50);color:var(--brand-700)}
.ico-green{background:var(--success-50);color:var(--success)}
.ico-amber{background:var(--warning-50);color:var(--warning)}
.ico-red{background:var(--danger-50);color:var(--danger)}

/* ---------- Buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;
  padding:10px 16px;border-radius:var(--radius-sm);font-weight:600;font-size:.9rem;
  transition:background .15s,box-shadow .15s,transform .05s;white-space:nowrap;min-height:42px}
.btn svg{width:17px;height:17px}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--brand);color:#fff;box-shadow:var(--shadow-sm)}
.btn-primary:hover{background:var(--brand-700)}
.btn-ghost{background:var(--surface);color:var(--text);border:1px solid var(--border)}
.btn-ghost:hover{background:var(--surface-2);border-color:var(--border-strong)}
.btn-success{background:var(--success);color:#fff}
.btn-success:hover{filter:brightness(.95)}
.btn-danger{background:var(--danger-50);color:var(--danger)}
.btn-danger:hover{background:#fee2e2}
.btn-sm{padding:7px 11px;min-height:34px;font-size:.84rem}
.btn-lg{padding:14px 22px;min-height:52px;font-size:1rem}
.btn:disabled{opacity:.55;cursor:not-allowed}
.btn-block{width:100%}

/* ---------- Forms ---------- */
.field{margin-bottom:16px}
.field label{display:block;font-size:.84rem;font-weight:600;color:var(--text-2);margin-bottom:6px}
.input,.select{width:100%;padding:11px 13px;border:1px solid var(--border-strong);border-radius:var(--radius-sm);
  background:var(--surface);color:var(--text);transition:border-color .15s,box-shadow .15s;min-height:44px}
.input:focus,.select:focus{outline:none;border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-100)}
.input::placeholder{color:var(--text-3)}
.hint{font-size:.78rem;color:var(--text-3);margin-top:5px}
.row{display:flex;gap:14px}
.row>*{flex:1}

/* ---------- Table ---------- */
.table-wrap{overflow-x:auto}
table{width:100%;border-collapse:collapse}
th{text-align:left;font-size:.76rem;font-weight:600;text-transform:uppercase;letter-spacing:.04em;
  color:var(--text-3);padding:12px 16px;border-bottom:1px solid var(--border);background:var(--surface-2)}
td{padding:13px 16px;border-bottom:1px solid var(--border);font-size:.9rem}
tbody tr:last-child td{border-bottom:none}
tbody tr{transition:background .12s}
tbody tr:hover{background:var(--surface-2)}
.t-right{text-align:right}.t-center{text-align:center}

/* ---------- Badges ---------- */
.badge{display:inline-flex;align-items:center;gap:5px;padding:3px 9px;border-radius:999px;
  font-size:.74rem;font-weight:600}
.badge-green{background:var(--success-50);color:var(--success)}
.badge-amber{background:var(--warning-50);color:var(--warning)}
.badge-red{background:var(--danger-50);color:var(--danger)}
.badge-gray{background:var(--surface-2);color:var(--text-2)}
.badge-blue{background:var(--brand-50);color:var(--brand-700)}

/* ---------- Tabs ---------- */
.tabs{display:flex;gap:4px;background:var(--surface-2);padding:4px;border-radius:var(--radius-sm);
  border:1px solid var(--border);width:fit-content}
.tab{padding:8px 16px;border-radius:6px;font-weight:600;font-size:.88rem;color:var(--text-2);transition:all .15s}
.tab.active{background:var(--surface);color:var(--text);box-shadow:var(--shadow-sm)}

/* ---------- Modal ---------- */
.modal-scrim{position:fixed;inset:0;background:rgba(15,23,42,.5);backdrop-filter:blur(2px);
  display:none;align-items:center;justify-content:center;z-index:100;padding:20px;animation:fade .15s}
.modal-scrim.show{display:flex}
.modal{background:var(--surface);border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);
  width:100%;max-width:520px;max-height:90vh;overflow-y:auto;animation:pop .2s}
.modal-lg{max-width:760px}
.modal-head{display:flex;align-items:center;justify-content:space-between;padding:20px 24px;border-bottom:1px solid var(--border)}
.modal-head h3{font-size:1.15rem;font-weight:700}
.modal-body{padding:24px}
.modal-foot{padding:18px 24px;border-top:1px solid var(--border);display:flex;gap:10px;justify-content:flex-end}
.x-btn{width:34px;height:34px;border-radius:8px;display:grid;place-items:center;color:var(--text-3)}
.x-btn:hover{background:var(--surface-2);color:var(--text)}
@keyframes fade{from{opacity:0}to{opacity:1}}
@keyframes pop{from{opacity:0;transform:scale(.96) translateY(8px)}to{opacity:1;transform:none}}

/* ---------- Toast ---------- */
.toasts{position:fixed;bottom:24px;right:24px;z-index:200;display:flex;flex-direction:column;gap:10px}
.toast{background:var(--text);color:#fff;padding:13px 18px;border-radius:var(--radius-sm);
  box-shadow:var(--shadow-lg);font-size:.9rem;font-weight:500;display:flex;align-items:center;gap:10px;
  animation:slidein .2s;max-width:360px}
.toast svg{width:18px;height:18px;flex-shrink:0}
.toast.ok{background:#065f46}.toast.err{background:#991b1b}
@keyframes slidein{from{opacity:0;transform:translateX(20px)}to{opacity:1;transform:none}}

/* ---------- Empty state ---------- */
.empty{text-align:center;padding:48px 24px;color:var(--text-3)}
.empty svg{width:48px;height:48px;margin-bottom:12px;opacity:.5}
.empty h4{font-size:1rem;font-weight:600;color:var(--text-2);margin-bottom:4px}

/* ---------- Login ---------- */
.login-wrap{min-height:100dvh;display:grid;place-items:center;padding:20px;
  background:linear-gradient(135deg,#eff6ff,#f1f5f9 60%)}
.login-card{background:var(--surface);border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);
  width:100%;max-width:400px;padding:36px 32px}
.login-brand{display:flex;flex-direction:column;align-items:center;gap:12px;margin-bottom:28px}
.login-brand .brand-mark{width:52px;height:52px;border-radius:14px}
.login-brand .brand-mark svg{width:28px;height:28px}

/* ---------- Utilities ---------- */
.flex{display:flex}.items-center{align-items:center}.justify-between{justify-content:space-between}
.gap-2{gap:8px}.gap-3{gap:12px}.gap-4{gap:16px}
.mt-2{margin-top:8px}.mt-3{margin-top:12px}.mt-4{margin-top:16px}.mt-6{margin-top:24px}
.mb-2{margin-bottom:8px}.mb-4{margin-bottom:16px}.mb-6{margin-bottom:24px}
.muted{color:var(--text-2)}.muted-3{color:var(--text-3)}
.fw-600{font-weight:600}.fw-700{font-weight:700}
.fs-sm{font-size:.85rem}.fs-lg{font-size:1.1rem}
.text-success{color:var(--success)}.text-danger{color:var(--danger)}.text-warning{color:var(--warning)}
.w-full{width:100%}.hidden{display:none!important}

/* ---------- POS specific ---------- */
.pos{display:grid;grid-template-columns:1fr 400px;gap:20px;align-items:start}
.pos-search{position:relative}
.pos-results{position:absolute;top:100%;left:0;right:0;background:var(--surface);
  border:1px solid var(--border);border-radius:var(--radius-sm);box-shadow:var(--shadow-lg);
  margin-top:6px;max-height:340px;overflow-y:auto;z-index:20;display:none}
.pos-results.show{display:block}
.pos-result{padding:12px 14px;display:flex;justify-content:space-between;align-items:center;
  cursor:pointer;border-bottom:1px solid var(--border)}
.pos-result:hover,.pos-result.hl{background:var(--brand-50)}
.cart{position:sticky;top:84px}
.cart-item{display:flex;align-items:center;gap:10px;padding:12px 0;border-bottom:1px solid var(--border)}
.qty-ctrl{display:flex;align-items:center;border:1px solid var(--border-strong);border-radius:8px;overflow:hidden}
.qty-ctrl button{width:30px;height:32px;display:grid;place-items:center;color:var(--text-2);font-weight:600}
.qty-ctrl button:hover{background:var(--surface-2)}
.qty-ctrl input{width:42px;text-align:center;border:none;border-left:1px solid var(--border);
  border-right:1px solid var(--border);min-height:32px;padding:0}
.qty-ctrl input:focus{outline:none}
.summary-row{display:flex;justify-content:space-between;padding:7px 0;font-size:.92rem}
.summary-row.total{font-size:1.3rem;font-weight:750;padding-top:14px;margin-top:6px;border-top:2px solid var(--border)}

/* product grid for POS quick add */
.prod-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(135px,1fr));gap:12px}
.prod-tile{border:1px solid var(--border);border-radius:var(--radius-sm);padding:14px;cursor:pointer;
  transition:border-color .15s,box-shadow .15s,transform .05s;background:var(--surface)}
.prod-tile:hover{border-color:var(--brand);box-shadow:var(--shadow-md)}
.prod-tile:active{transform:scale(.98)}
.prod-tile .pt-name{font-weight:600;font-size:.88rem;margin-bottom:4px;line-height:1.3}
.prod-tile .pt-price{color:var(--brand-700);font-weight:700}
.prod-tile .pt-stock{font-size:.74rem;color:var(--text-3);margin-top:2px}

/* barcode label */
.label-card{border:1px dashed var(--border-strong);border-radius:var(--radius-sm);padding:16px;
  text-align:center;background:#fff}
.label-card svg{max-width:100%}

/* ---------- Responsive ---------- */
@media(max-width:1024px){
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .pos{grid-template-columns:1fr}
  .cart{position:static}
}
@media(max-width:768px){
  .sidebar{transform:translateX(-100%);transition:transform .25s;box-shadow:var(--shadow-lg)}
  .sidebar.open{transform:none}
  .main{margin-left:0}
  .menu-btn{display:grid;place-items:center;width:40px;height:40px;border-radius:8px;color:var(--text-2)}
  .menu-btn:hover{background:var(--surface-2)}
  .content{padding:18px 16px}
  .topbar{padding:0 16px}
  .grid-4,.grid-3,.grid-2{grid-template-columns:1fr}
  .scrim-nav{position:fixed;inset:0;background:rgba(0,0,0,.4);z-index:35;display:none}
  .scrim-nav.show{display:block}
}