/* ============ THEME VARIABLES ============ */
:root {
  --bg: #f4f6f9;
  --panel: #ffffff;
  --panel-2: #f9fafb;
  --border: #e5e7eb;
  --border-light: #f3f4f6;
  --text: #111827;
  --text-muted: #6b7280;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --danger: #dc2626;
  --danger-bg: #fee2e2;
  --success: #065f46;
  --success-bg: #d1fae5;
  --sidebar-bg: #111827;
  --sidebar-text: #d1d5db;
  --sidebar-muted: #9ca3af;
  --sidebar-hover: #1f2937;
  --sidebar-border: #1f2937;
  --sidebar-link: #60a5fa;
  --shadow: 0 1px 3px rgba(0,0,0,.06);
  --input-bg: #ffffff;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --panel: #1e293b;
  --panel-2: #0f172a;
  --border: #334155;
  --border-light: #1e293b;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --primary: #3b82f6;
  --primary-hover: #60a5fa;
  --primary-light: #1e3a5f;
  --danger: #f87171;
  --danger-bg: #4c1d1d;
  --success: #4ade80;
  --success-bg: #064e3b;
  --sidebar-bg: #020617;
  --sidebar-text: #cbd5e1;
  --sidebar-muted: #64748b;
  --sidebar-hover: #1e293b;
  --sidebar-border: #1e293b;
  --sidebar-link: #60a5fa;
  --shadow: 0 1px 3px rgba(0,0,0,.5);
  --input-bg: #0f172a;
}

/* ============ BASE ============ */
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--text);font-size:14px;transition:background .2s,color .2s}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}

/* ============ LAYOUT ============ */
.layout{display:flex;min-height:100vh}
.sidebar{width:220px;background:var(--sidebar-bg);color:var(--sidebar-text);padding:1rem 0;flex-shrink:0;display:flex;flex-direction:column}
.sidebar .brand{padding:0 1rem 1rem;font-size:1.1rem;color:#fff;border-bottom:1px solid var(--sidebar-border);margin-bottom:.5rem}
.sidebar nav{display:flex;flex-direction:column}
.sidebar nav a{color:var(--sidebar-text);padding:.6rem 1rem;font-size:.9rem;border-left:3px solid transparent}
.sidebar nav a:hover,.sidebar nav a.active{background:var(--sidebar-hover);color:#fff;border-left-color:var(--primary);text-decoration:none}
.sidebar-footer{margin-top:auto;padding:1rem;font-size:.8rem;color:var(--sidebar-muted);border-top:1px solid var(--sidebar-border)}
.sidebar-footer a{color:var(--sidebar-link)}
.main{flex:1;display:flex;flex-direction:column;min-width:0}
.topbar{background:var(--panel);padding:1rem 1.5rem;border-bottom:1px solid var(--border);display:flex;justify-content:space-between;align-items:center}
.topbar h2{font-size:1.2rem}
.content{padding:1.5rem;flex:1;overflow:auto}

/* ============ THEME TOGGLE ============ */
.theme-toggle{background:var(--panel-2);border:1px solid var(--border);color:var(--text);width:38px;height:38px;border-radius:8px;font-size:1.1rem;cursor:pointer;display:flex;align-items:center;justify-content:center}
.theme-toggle:hover{background:var(--hover, #e5e7eb)}
[data-theme="dark"] .theme-toggle:hover{background:var(--border)}

/* ============ FORMS ============ */
.form-card{background:var(--panel);padding:1rem;border-radius:8px;margin-bottom:1.2rem;box-shadow:var(--shadow)}
.form-card h3{margin-bottom:1rem;font-size:1rem;color:var(--text)}
.form-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:.75rem;margin-bottom:1rem}
.form-grid label{display:flex;flex-direction:column;font-size:.8rem;color:var(--text-muted);gap:.25rem}
input,select,textarea{border:1px solid var(--border);border-radius:6px;padding:.5rem;font-size:.9rem;font-family:inherit;background:var(--input-bg);color:var(--text)}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--primary)}
button,.btn-primary,.btn-secondary{cursor:pointer;border:none;padding:.55rem 1rem;border-radius:6px;font-size:.9rem;font-weight:500}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-hover)}
.btn-secondary{background:var(--border);color:var(--text)}
.btn-secondary:hover{filter:brightness(.95)}
.big{width:100%;padding:.75rem;font-size:1rem}

/* ============ TABLES ============ */
.table{width:100%;border-collapse:collapse;background:var(--panel);border-radius:8px;overflow:hidden;box-shadow:var(--shadow);margin-bottom:1rem}
.table th,.table td{padding:.6rem .75rem;text-align:left;border-bottom:1px solid var(--border-light);font-size:.85rem}
.table th{background:var(--panel-2);font-weight:600;color:var(--text)}
.table tr:hover td{background:var(--panel-2)}
.low{color:var(--danger);font-weight:600}

/* ============ STATS ============ */
.stats-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:1rem;margin-bottom:1.2rem}
.stat-card{background:var(--panel);padding:1rem;border-radius:8px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:.25rem}
.stat-card span{font-size:.8rem;color:var(--text-muted)}
.stat-card strong{font-size:1.4rem;color:var(--text)}
.stat-card.warn strong{color:var(--danger)}

/* ============ LOGIN ============ */
.login-page{display:flex;align-items:center;justify-content:center;min-height:100vh;background:var(--sidebar-bg)}
.login-form{background:var(--panel);padding:2rem;border-radius:10px;width:340px;max-width:90vw;display:flex;flex-direction:column;gap:.75rem;box-shadow:0 10px 25px rgba(0,0,0,.3)}
.login-form h2{text-align:center;margin-bottom:.5rem;color:var(--text)}
.login-form label{display:flex;flex-direction:column;font-size:.85rem;color:var(--text-muted);gap:.25rem}
.login-form button{background:var(--primary);color:#fff;padding:.65rem;border-radius:6px;font-weight:600;margin-top:.5rem}
.error{color:var(--danger);text-align:center;font-size:.85rem;background:var(--danger-bg);padding:.5rem;border-radius:6px}
.success{color:var(--success);background:var(--success-bg);padding:.6rem 1rem;border-radius:6px;margin-bottom:1rem}

/* ============ POS ============ */
.pos-wrap{display:grid;grid-template-columns:1fr 380px;gap:1rem;height:calc(100vh - 130px)}
.pos-products{background:var(--panel);border-radius:8px;padding:1rem;overflow:auto;box-shadow:var(--shadow)}
.search-input{width:100%;padding:.65rem;border:1px solid var(--border);border-radius:6px;margin-bottom:1rem;background:var(--input-bg);color:var(--text)}
.product-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:.75rem}
.product-card{background:var(--panel-2);border:1px solid var(--border);border-radius:8px;padding:.75rem;cursor:pointer;transition:.15s}
.product-card:hover{background:var(--primary-light);border-color:var(--primary);transform:translateY(-1px)}
.pname{font-weight:600;font-size:.85rem;margin-bottom:.3rem;color:var(--text)}
.pmeta{font-size:.7rem;color:var(--text-muted)}
.pprice{font-weight:700;color:var(--primary);margin-top:.4rem}
.pos-cart{background:var(--panel);border-radius:8px;padding:1rem;display:flex;flex-direction:column;gap:.5rem;box-shadow:var(--shadow);overflow:auto}
.cart-items{flex:1;min-height:100px;overflow:auto;border:1px solid var(--border);border-radius:6px;padding:.5rem}
.cart-row{display:grid;grid-template-columns:1fr auto 24px;gap:.4rem;align-items:center;padding:.4rem 0;border-bottom:1px solid var(--border-light);font-size:.85rem;color:var(--text)}
.cart-row:last-child{border-bottom:none}
.qty-in{width:60px;padding:.25rem}
.del-row{background:var(--danger-bg);color:var(--danger);border-radius:4px;padding:.15rem .4rem;cursor:pointer}
.cart-totals{display:flex;flex-direction:column;gap:.4rem;font-size:.85rem;color:var(--text)}
.cart-totals>div{display:flex;justify-content:space-between;align-items:center;gap:.5rem}
.cart-totals input[type=number]{width:90px;padding:.35rem}
.cart-totals .grand{font-weight:700;font-size:1.05rem;color:var(--text);border-top:1px solid var(--border);padding-top:.5rem;margin-top:.3rem}
.pay-method{display:flex;gap:.75rem;font-size:.85rem;padding:.3rem 0}
.pay-method label{display:flex;align-items:center;gap:.3rem}
.empty{color:var(--text-muted);text-align:center;padding:1rem;font-size:.85rem}

/* ============ CHARTS ============ */
.charts-grid{display:grid;grid-template-columns:2fr 1fr;gap:1rem;margin-bottom:1.2rem}
.chart-card{background:var(--panel);border-radius:8px;padding:1rem;box-shadow:var(--shadow)}
.chart-card h3{margin-bottom:.75rem;font-size:.95rem;color:var(--text)}
.chart-card canvas{max-height:280px}

/* ============ RECEIPT (A4) ============ */
.receipt-page{background:var(--bg);padding:1rem;font-family:monospace;color:var(--text)}
.receipt{max-width:380px;margin:0 auto;background:var(--panel);padding:1.5rem;border-radius:6px;box-shadow:var(--shadow)}
.receipt h2{text-align:center;font-size:1.15rem;margin-bottom:.5rem}
.receipt p{font-size:.85rem;text-align:center}
.receipt hr{border:none;border-top:1px dashed var(--border);margin:1rem 0}
.receipt table{width:100%;font-size:.8rem;margin:.75rem 0}
.receipt th,.receipt td{padding:.3rem;text-align:left}
.receipt th{border-bottom:1px dashed var(--border)}
.totals div{display:flex;justify-content:space-between;font-size:.85rem;padding:.2rem 0}
.totals .grand{font-weight:700;border-top:1px dashed var(--border);padding-top:.4rem;margin-top:.3rem}
.receipt-actions{display:flex;gap:.5rem;justify-content:center;margin-top:1rem;flex-wrap:wrap}
.receipt-actions button,.receipt-actions a{background:var(--primary);color:#fff;padding:.5rem 1rem;border-radius:6px;border:none;cursor:pointer;text-decoration:none;font-size:.85rem}
.receipt-actions a{background:var(--text-muted)}

/* ============ RESPONSIVE ============ */
@media (max-width:900px){
  .layout{flex-direction:column}
  .sidebar{width:100%;flex-direction:row;overflow-x:auto;padding:0}
  .sidebar .brand{padding:.75rem;border:none;white-space:nowrap;font-size:.95rem}
  .sidebar nav{flex-direction:row}
  .sidebar nav a{white-space:nowrap;border-left:none;border-bottom:3px solid transparent;padding:.6rem}
  .sidebar nav a.active{border-left:none;border-bottom-color:var(--primary)}
  .sidebar-footer{display:none}
  .pos-wrap{grid-template-columns:1fr;height:auto}
  .charts-grid{grid-template-columns:1fr}
}