/* ============================================================
   BillBook - Global Styles
   Modern, minimal, white background, green accent, touch-friendly
   ============================================================ */
:root {
    --green: #16a34a;
    --green-dark: #15803d;
    --green-light: #dcfce7;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-400: #94a3b8;
    --gray-600: #475569;
    --gray-900: #0f172a;
    --red: #dc2626;
    --amber: #d97706;
    --radius: 14px;
    --shadow: 0 2px 10px rgba(15, 23, 42, 0.06);
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: 'Segoe UI', Roboto, -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--gray-50);
    color: var(--gray-900);
    font-size: 16px;
}

a { text-decoration: none; color: inherit; }
button { font-family: inherit; cursor: pointer; }

/* ---------- App shell ---------- */
.app-shell { display: flex; min-height: 100vh; }

.sidebar {
    width: 220px;
    background: #fff;
    border-right: 1px solid var(--gray-200);
    display: flex;
    flex-direction: column;
    position: sticky;
    top: 0;
    height: 100vh;
    flex-shrink: 0;
}
.sidebar-logo {
    font-size: 20px;
    font-weight: 800;
    padding: 22px 20px;
    color: var(--green-dark);
    border-bottom: 1px solid var(--gray-200);
}
.sidebar nav { display: flex; flex-direction: column; padding: 12px; gap: 4px; flex: 1; }
.sidebar nav a {
    padding: 12px 14px;
    border-radius: 10px;
    font-weight: 600;
    color: var(--gray-600);
    font-size: 15px;
}
.sidebar nav a:hover { background: var(--gray-100); }
.sidebar nav a.active { background: var(--green-light); color: var(--green-dark); }
.sidebar-footer {
    padding: 16px 20px;
    border-top: 1px solid var(--gray-200);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: var(--gray-400);
}
.logout-link { color: var(--red); font-weight: 700; }

.main-content { flex: 1; padding: 24px 28px; max-width: 100%; overflow-x: hidden; }

/* ---------- Cards ---------- */
.card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    border: 1px solid var(--gray-200);
}
.card h3 { margin-top: 0; }

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 12px;
}
.page-header h1 { font-size: 24px; margin: 0; }

/* ---------- Buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: none;
    border-radius: 12px;
    padding: 12px 20px;
    font-weight: 700;
    font-size: 15px;
    transition: transform .05s ease, background .15s ease;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--green); color: #fff; }
.btn-primary:hover { background: var(--green-dark); }
.btn-secondary { background: var(--gray-100); color: var(--gray-900); }
.btn-secondary:hover { background: var(--gray-200); }
.btn-danger { background: #fee2e2; color: var(--red); }
.btn-danger:hover { background: #fecaca; }
.btn-outline { background: #fff; border: 2px solid var(--green); color: var(--green-dark); }
.btn-lg { padding: 16px 24px; font-size: 17px; }
.btn-xl { padding: 20px 28px; font-size: 19px; border-radius: 16px; }
.btn-block { width: 100%; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

/* ---------- Forms ---------- */
label { display: block; font-weight: 700; font-size: 13px; margin: 12px 0 6px; color: var(--gray-600); }
input, select, textarea {
    width: 100%;
    padding: 12px 14px;
    border-radius: 10px;
    border: 1.5px solid var(--gray-200);
    font-size: 16px;
    background: #fff;
    color: var(--gray-900);
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--green);
    box-shadow: 0 0 0 3px var(--green-light);
}
.input-lg { padding: 16px; font-size: 18px; }
.form-row { display: flex; gap: 12px; }
.form-row > div { flex: 1; }

/* ---------- Tables ---------- */
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--gray-100); font-size: 14.5px; }
th { color: var(--gray-600); font-size: 12.5px; text-transform: uppercase; letter-spacing: .03em; }
tr:hover td { background: var(--gray-50); }

/* ---------- Login page ---------- */
.login-body {
    display: flex; align-items: center; justify-content: center;
    min-height: 100vh; background: linear-gradient(160deg, var(--green-light), var(--gray-50));
}
.login-card {
    background: #fff; padding: 40px; border-radius: 20px; box-shadow: var(--shadow);
    width: 360px; text-align: center;
}
.login-logo { font-size: 28px; font-weight: 800; color: var(--green-dark); }
.login-sub { color: var(--gray-400); margin-bottom: 10px; }
.login-hint { margin-top: 14px; font-size: 12px; color: var(--gray-400); }
.alert { padding: 10px 14px; border-radius: 10px; margin-bottom: 10px; font-size: 14px; }
.alert-error { background: #fee2e2; color: var(--red); }
.alert-success { background: var(--green-light); color: var(--green-dark); }

/* ---------- Dashboard ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 16px; margin-bottom: 24px; }
.stat-card { background: #fff; border-radius: var(--radius); padding: 18px 20px; box-shadow: var(--shadow); border: 1px solid var(--gray-200); }
.stat-card .label { font-size: 13px; color: var(--gray-400); font-weight: 600; }
.stat-card .value { font-size: 26px; font-weight: 800; margin-top: 4px; }
.stat-card.green .value { color: var(--green-dark); }
.stat-card.amber .value { color: var(--amber); }
.stat-card.red .value { color: var(--red); }

/* ---------- Products page ---------- */
.product-form-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 14px; align-items: end; }
.advanced-box { display: none; margin-top: 10px; padding-top: 10px; border-top: 1px dashed var(--gray-200); }
.advanced-box.open { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.toggle-advanced { background: none; border: none; color: var(--green-dark); font-weight: 700; font-size: 14px; margin-top: 10px; padding: 4px 0; }

.badge { display: inline-block; padding: 3px 9px; border-radius: 999px; font-size: 12px; font-weight: 700; }
.badge-low { background: #fee2e2; color: var(--red); }
.badge-ok { background: var(--green-light); color: var(--green-dark); }

/* ---------- Billing / POS ---------- */
.pos-grid { display: grid; grid-template-columns: 1fr 1.3fr; gap: 20px; align-items: start; }
@media (max-width: 1100px) { .pos-grid { grid-template-columns: 1fr; } }

.pos-search-box { position: relative; margin-bottom: 14px; }
.search-results {
    position: absolute; top: 100%; left: 0; right: 0; background: #fff;
    border: 1px solid var(--gray-200); border-radius: 12px; box-shadow: var(--shadow);
    max-height: 340px; overflow-y: auto; z-index: 50; margin-top: 6px;
}
.search-result-item { padding: 12px 14px; border-bottom: 1px solid var(--gray-100); display: flex; justify-content: space-between; cursor: pointer; }
.search-result-item:hover, .search-result-item.active { background: var(--green-light); }
.search-result-item .name { font-weight: 700; }
.search-result-item .meta { font-size: 12px; color: var(--gray-400); }
.search-result-item .price { font-weight: 700; color: var(--green-dark); }

.quick-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; margin-top: 10px; }
.quick-chip {
    background: var(--gray-100); border-radius: 10px; padding: 10px 12px; cursor: pointer; font-size: 14px;
    display: flex; justify-content: space-between; border: 1px solid transparent;
}
.quick-chip:hover { border-color: var(--green); background: var(--green-light); }

.bill-table-wrap { max-height: 42vh; overflow-y: auto; border: 1px solid var(--gray-200); border-radius: 12px; }
.qty-input { width: 64px; padding: 6px 8px; text-align: center; }
.disc-input { width: 64px; padding: 6px 8px; text-align: center; }
.remove-item { color: var(--red); font-weight: 800; font-size: 18px; background: none; border: none; }

.totals-box { margin-top: 16px; background: var(--gray-50); border-radius: 12px; padding: 16px; }
.totals-row { display: flex; justify-content: space-between; padding: 6px 0; font-size: 15px; }
.totals-row.grand { font-size: 22px; font-weight: 800; color: var(--green-dark); border-top: 2px dashed var(--gray-200); margin-top: 6px; padding-top: 12px; }

.payment-methods { display: flex; gap: 8px; margin-top: 10px; flex-wrap: wrap; }
.payment-methods button {
    flex: 1; padding: 12px; border-radius: 10px; border: 2px solid var(--gray-200); background: #fff; font-weight: 700; min-width: 90px;
}
.payment-methods button.selected { border-color: var(--green); background: var(--green-light); color: var(--green-dark); }

.action-bar { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-top: 18px; }
.action-bar .btn { padding: 16px 8px; font-size: 14px; }

.held-bills-strip { display: flex; gap: 10px; overflow-x: auto; margin-bottom: 14px; }
.held-chip { background: #fff7ed; border: 1px solid #fed7aa; border-radius: 10px; padding: 8px 14px; white-space: nowrap; font-size: 13px; font-weight: 700; color: var(--amber); }

kbd { background: var(--gray-100); border-radius: 6px; padding: 2px 6px; font-size: 12px; border: 1px solid var(--gray-200); }

/* ---------- Utility ---------- */
.text-right { text-align: right; }
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.flex { display: flex; }
.gap-8 { gap: 8px; }
.hidden { display: none !important; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
    .sidebar { position: fixed; left: -220px; z-index: 100; transition: left .2s; box-shadow: var(--shadow); }
    .sidebar.open { left: 0; }
    .main-content { padding: 16px; }
    .product-form-grid { grid-template-columns: 1fr; }
    .advanced-box.open { grid-template-columns: 1fr 1fr; }
    .action-bar { grid-template-columns: repeat(2, 1fr); }
}

/* ---------- Print ---------- */
@media print {
    body * { visibility: hidden; }
    .print-area, .print-area * { visibility: visible; }
    .print-area { position: absolute; left: 0; top: 0; width: 100%; }
}