:root {
    --primary-color: #4f46e5;
    --primary-gradient: linear-gradient(135deg, #6366f1, #3b82f6);
    --secondary-color: #f43f5e;
    --secondary-gradient: linear-gradient(135deg, #fb7185, #f43f5e);
    --background-color: #f8fafc;
    --surface-color: rgba(255, 255, 255, 0.85);
    --surface-solid: #ffffff;
    --text-color: #0f172a;
    --text-muted: #64748b;
    --border-color: rgba(226, 232, 240, 0.8);
    --success-color: #10b981;
    --success-gradient: linear-gradient(135deg, #34d399, #10b981);
    --danger-color: #ef4444;
    --danger-gradient: linear-gradient(135deg, #f87171, #ef4444);
    --radius: 16px;
    --radius-sm: 10px;
    --shadow: 0 8px 30px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 10px 40px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.1);
    --glass-blur: blur(16px);
    --transition: all 0.3s cubic-bezier(0.25, 1, 0.5, 1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
    background-attachment: fixed;
    color: var(--text-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Navbar */
.navbar {
    background: linear-gradient(135deg, #1e293b, #0f172a);
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 2rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-menu-container {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-brand {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    background: linear-gradient(135deg, #a5b4fc, #818cf8);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 1.75rem;
}

.nav-links a {
    color: #94a3b8;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
    position: relative;
    padding: 0.25rem 0;
}

.nav-links a:hover, .nav-links a.active {
    color: #ffffff;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: #818cf8;
    transition: var(--transition);
    border-radius: 2px;
}

.nav-links a:hover::after, .nav-links a.active::after {
    width: 100%;
}

.nav-user {
    display: flex;
    align-items: center;
}

/* Container */
.container {
    max-width: 1280px;
    margin: 2rem auto;
    padding: 0 1.5rem;
}

/* Utilities */
.text-center { text-align: center; }
.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }
.mb-1 { margin-bottom: 1rem; }
.mb-2 { margin-bottom: 2rem; }
.flex { display: flex; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }
.text-muted { color: var(--text-muted); }

/* Buttons */
.btn {
    padding: 0.6rem 1.25rem;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.9rem;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn:active {
    transform: scale(0.95);
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(79, 70, 229, 0.3);
}
.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(79, 70, 229, 0.4);
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--secondary-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(244, 63, 94, 0.3);
}
.btn-secondary:hover {
    box-shadow: 0 6px 20px rgba(244, 63, 94, 0.4);
    transform: translateY(-2px);
}

.btn-success {
    background: var(--success-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
}
.btn-success:hover {
    box-shadow: 0 6px 20px rgba(16, 185, 129, 0.4);
    transform: translateY(-2px);
}

.btn-danger {
    background: var(--danger-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.3);
}
.btn-danger:hover {
    box-shadow: 0 6px 20px rgba(239, 68, 68, 0.4);
    transform: translateY(-2px);
}

.btn-outline {
    background-color: transparent;
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
}
.btn-outline:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: white;
}

.btn-block { display: flex; width: 100%; }

/* Forms */
.form-group {
    margin-bottom: 1.25rem;
}
.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    font-size: 0.85rem;
    color: #475569;
}
.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-family: inherit;
    transition: var(--transition);
    background-color: #f8fafc;
}
.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    background-color: white;
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

/* Cards */
.card {
    background-color: var(--surface-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    border: 1px solid rgba(226, 232, 240, 0.8);
}

/* POS Layout */
.pos-layout {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    height: calc(100vh - 160px);
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 1.25rem;
    overflow-y: auto;
    padding-right: 0.75rem;
}

.product-card {
    background: var(--surface-color);
    border-radius: var(--radius);
    padding: 1.25rem;
    text-align: center;
    cursor: pointer;
    box-shadow: var(--shadow);
    border: 1px solid rgba(226, 232, 240, 0.8);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 180px;
}

.product-card:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.product-name {
    font-weight: 700;
    margin-bottom: 0.4rem;
    font-size: 1.1rem;
    color: #1e293b;
}
.product-meta {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    background: #f1f5f9;
    padding: 3px 8px;
    border-radius: 20px;
    display: inline-block;
}
.product-price {
    font-size: 1.4rem;
    font-weight: 800;
    color: #10b981;
    margin: 0.5rem 0;
}
.product-stock {
    font-size: 0.85rem;
    margin-top: 0.5rem;
    color: #64748b;
    font-weight: 500;
}
.stock-low {
    color: var(--danger-color) !important;
    font-weight: 700;
}

/* Cart */
.cart-panel {
    background: var(--surface-color);
    border-radius: var(--radius);
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(226, 232, 240, 0.8);
    overflow: hidden;
}

.cart-header {
    padding: 1.25rem;
    border-bottom: 1px solid var(--border-color);
    font-size: 1.3rem;
    font-weight: 700;
    background: #f8fafc;
    color: #1e293b;
}

.cart-items {
    flex-grow: 1;
    overflow-y: auto;
    padding: 1.25rem;
}

.cart-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 0.75rem;
    margin-bottom: 0.75rem;
    border-bottom: 1px solid #f1f5f9;
}

.cart-item-info { flex-grow: 1; }
.cart-item-info strong { color: #1e293b; font-size: 0.95rem; }
.cart-item-controls { display: flex; align-items: center; gap: 0.5rem; }
.cart-item-controls button {
    background: #f1f5f9;
    border: none;
    border-radius: 6px;
    width: 28px;
    height: 28px;
    cursor: pointer;
    font-weight: bold;
    color: #475569;
    transition: var(--transition);
}
.cart-item-controls button:hover {
    background: var(--primary-color);
    color: white;
}

.cart-footer {
    padding: 1.25rem;
    border-top: 1px solid var(--border-color);
    background: #f8fafc;
}

.cart-total {
    display: flex;
    justify-content: space-between;
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 1.25rem;
    color: #1e293b;
}

/* Tables */
.table-container {
    overflow-x: auto;
    background: var(--surface-solid);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}
table {
    width: 100%;
    border-collapse: collapse;
}
th, td {
    padding: 0.85rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.95rem;
}
th {
    background-color: #f8fafc;
    font-weight: 700;
    color: #475569;
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 0.5px;
    border-bottom: 2px solid var(--border-color);
}
tbody tr {
    transition: var(--transition);
}
tbody tr:hover {
    background: #f1f5f9;
}

/* Modals */
.modal-backdrop {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: var(--transition);
}
.modal-backdrop.show { display: flex; }
.modal-content {
    background: var(--surface-solid);
    padding: 2.5rem;
    border-radius: var(--radius);
    width: 100%;
    max-width: 500px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(255, 255, 255, 0.5);
    animation: modalFadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}
.modal-header h3 {
    font-size: 1.35rem;
    font-weight: 700;
    color: #1e293b;
}
.modal-close {
    background: #f1f5f9;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #64748b;
    transition: var(--transition);
}
.modal-close:hover {
    background: #e2e8f0;
    color: #0f172a;
}

@keyframes modalFadeIn {
    from {
        opacity: 0;
        transform: translateY(10px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.35rem 0.75rem;
    font-size: 0.8rem;
    font-weight: 700;
    border-radius: 50px;
    background: #e2e8f0;
    color: #475569;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}
.badge-success {
    background: rgba(16, 185, 129, 0.15);
    color: #047857;
}
.badge-danger {
    background: rgba(239, 68, 68, 0.15);
    color: #b91c1c;
}
.badge-primary {
    background: rgba(79, 70, 229, 0.15);
    color: #4338ca;
}

/* --- MOBILE RESPONSIVENESS OVERHAUL --- */

/* Base Viewport & Responsive Variable Overrides */
:root {
    --bp-lg: 1024px;
    --bp-md: 768px;
    --bp-sm: 480px;
}

/* Nav toggle button styles (Desktop hidden) */
.nav-toggle {
    display: none;
    background: transparent;
    border: none;
    cursor: pointer;
    flex-direction: column;
    justify-content: space-between;
    width: 26px;
    height: 18px;
    padding: 0;
    z-index: 110;
}

.nav-toggle .hamburger-bar {
    width: 100%;
    height: 3px;
    background-color: #ffffff;
    border-radius: 3px;
    transition: var(--transition);
    transform-origin: left center;
}

/* Hamburger active transformations */
.nav-toggle.active .hamburger-bar:nth-child(1) {
    transform: rotate(45deg) translateY(-2px);
    background-color: var(--secondary-color);
}
.nav-toggle.active .hamburger-bar:nth-child(2) {
    opacity: 0;
    width: 0;
}
.nav-toggle.active .hamburger-bar:nth-child(3) {
    transform: rotate(-45deg) translateY(2px);
    background-color: var(--secondary-color);
}

/* Picker Product Modal Row styling */
.picker-products-list {
    background: var(--surface-color);
}

.picker-product-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.85rem 1rem;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    transition: var(--transition);
}

.picker-product-row:hover, .picker-product-row:active {
    background-color: #f8fafc;
}

.picker-product-info {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
}

.picker-product-name {
    font-weight: 600;
    color: #1e293b;
    font-size: 0.95rem;
}

.picker-product-meta {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.15rem;
}

.picker-product-action {
    display: flex;
    align-items: center;
    gap: 0.85rem;
}

.picker-product-price {
    font-weight: 700;
    color: #10b981;
    font-size: 1rem;
}

.picker-product-stock {
    font-size: 0.8rem;
    color: var(--text-muted);
    background: #f1f5f9;
    padding: 2px 8px;
    border-radius: 20px;
}

.picker-product-stock.stock-low {
    color: var(--danger-color);
    background: rgba(239, 68, 68, 0.1);
    font-weight: 700;
}

/* Active POS Panels (default display on desktop) */
.pos-panel {
    display: flex;
    flex-direction: column;
}

/* Responsive Breakpoint: Tablet & Mobile (<= 768px) */
@media (max-width: 768px) {
    .hide-on-mobile { display: none !important; }
    .nav-toggle {
        display: flex;
    }

    .navbar {
        padding: 1rem 1.5rem;
    }

    .nav-menu-container {
        position: fixed;
        top: 0;
        right: 0;
        bottom: 0;
        width: 280px;
        background: rgba(15, 23, 42, 0.93); /* Dark glassmorphism */
        backdrop-filter: blur(16px);
        -webkit-backdrop-filter: blur(16px);
        box-shadow: -10px 0 30px rgba(0, 0, 0, 0.15);
        display: flex;
        flex-direction: column;
        justify-content: space-between;
        padding: 5rem 2rem 3rem 2rem;
        z-index: 105;
        transform: translateX(100%);
        transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
        border-left: 1px solid rgba(255, 255, 255, 0.08);
    }

    .nav-menu-container.active {
        transform: translateX(0);
    }

    .nav-links {
        flex-direction: column;
        gap: 1.5rem;
    }

    .nav-links a {
        font-size: 1.2rem;
        display: block;
        padding: 0.5rem 0;
        width: 100%;
        color: #cbd5e1;
    }

    .nav-links a::after {
        bottom: 0;
    }

    .nav-user {
        width: 100%;
        border-top: 1px solid rgba(255, 255, 255, 0.1);
        padding-top: 1.5rem;
    }

    .nav-user .btn-outline {
        width: 100%;
        padding: 0.8rem;
    }

    /* Container Spacing */
    .container {
        margin: 1rem auto;
        padding: 0 1rem;
    }

    /* POS Mobile Pivot Styles */
    .pos-layout {
        display: block !important;
        height: auto !important;
    }

    /* Hide standard desktop product catalog grid on mobile */
    #productsPanel {
        display: none !important;
    }

    /* Display Cart Full Width by default on mobile */
    #cartPanel {
        display: flex !important;
        width: 100% !important;
        height: calc(100vh - 160px) !important;
        min-height: 450px !important;
    }

    .mobile-only-inline {
        display: inline-flex !important;
    }

    /* Pages titles & action headers styling */
    .flex.justify-between.align-center.mb-2 {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
        margin-bottom: 1.25rem;
    }

    .flex.justify-between.align-center.mb-2 h2 {
        font-size: 1.5rem;
    }

    .flex.justify-between.align-center.mb-2 .btn {
        width: 100%;
    }

    /* Table Adjustments */
    th, td {
        padding: 0.8rem 1rem;
        font-size: 0.85rem;
    }

    /* Modals Responsive bottom-sheet scaling */
    .modal-backdrop {
        align-items: flex-end; /* Slide up from bottom on mobile */
    }

    .modal-content {
        max-width: 100% !important;
        width: 100% !important;
        border-radius: 20px 20px 0 0 !important;
        padding: 1.5rem;
        margin-bottom: 0;
        box-shadow: 0 -10px 25px rgba(0,0,0,0.15);
        animation: modalSlideUp 0.35s cubic-bezier(0.16, 1, 0.3, 1);
    }

    @keyframes modalSlideUp {
        from {
            transform: translateY(100%);
        }
        to {
            transform: translateY(0);
        }
    }

    .modal-header h3 {
        font-size: 1.2rem;
    }

    /* Form flex-rows stacking */
    .flex {
        flex-direction: column;
        gap: 0 !important; /* Stack vertically */
    }
    
    .modal-content .flex {
        flex-direction: column;
        gap: 0 !important;
    }

    .modal-content .form-group {
        flex: none !important;
        width: 100%;
    }

    .modal-content .flex[style*="gap"] {
        gap: 0 !important;
    }
    
    .modal-content .flex.justify-between {
        flex-direction: row;
        gap: 1rem !important;
    }
    
    .modal-content .flex.justify-between .btn {
        flex: 1;
    }

    /* Customer Purchase History Modal stats grid stacking */
    #historyModal div[style*="grid-template-columns"] {
        grid-template-columns: 1fr !important;
        gap: 0.75rem !important;
    }

    /* Purchase order line item row stacking */
    .purchase-line-row {
        flex-direction: column;
        align-items: stretch;
        padding: 1rem;
        background: #f8fafc;
        border-radius: var(--radius-sm);
        border: 1px solid var(--border-color);
        gap: 0.5rem !important;
    }

    .purchase-line-row select,
    .purchase-line-row input {
        width: 100% !important;
        margin: 0 !important;
    }
    
    .purchase-line-row .btn-danger {
        align-self: flex-end;
        width: auto !important;
        padding: 0.4rem 0.8rem;
    }
}

/* Small Smartphone Optimization (<= 480px) */
@media (max-width: 480px) {
    .dashboard-grid {
        grid-template-columns: 1fr !important;
        gap: 1rem;
    }
    
    .stat-card {
        padding: 1rem;
    }

    .stat-info h3 {
        font-size: 1.3rem;
    }

    .navbar {
        padding: 0.85rem 1rem;
    }

    .nav-brand {
        font-size: 1.4rem;
    }

    .modal-content .flex.justify-between {
        flex-direction: column-reverse; /* Stack buttons vertically, cancel on bottom */
    }
    
    .modal-content .flex.justify-between .btn {
        width: 100%;
    }
}

/* --- CHECKOUT SPECIFIC UI SYSTEM --- */

/* Payment Methods Grid */
.payment-methods-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
    margin-top: 0.25rem;
}

.payment-method-card {
    background: #f8fafc;
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.85rem 0.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
}

.payment-method-card:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
    transform: translateY(-2px);
}

.payment-method-card.active {
    background: rgba(99, 102, 241, 0.06);
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
    transform: translateY(-2px) scale(1.02);
}

.payment-method-icon {
    font-size: 1.5rem;
    transition: var(--transition);
}

.payment-method-card:active .payment-method-icon {
    transform: scale(1.2);
}

.payment-method-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: #475569;
    transition: var(--transition);
}

.payment-method-card.active .payment-method-label {
    color: var(--primary-color);
}

/* Customer Options Segmented Toggle Control */
.customer-options-toggle {
    display: flex;
    background: #e2e8f0;
    border-radius: var(--radius);
    padding: 0.25rem;
    margin-bottom: 1.25rem;
    border: 1px solid var(--border-color);
}

.cust-toggle-btn {
    flex: 1;
    background: transparent;
    border: none;
    padding: 0.6rem 0.25rem;
    font-size: 0.85rem;
    font-weight: 600;
    color: #475569;
    border-radius: calc(var(--radius) - 2px);
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    font-family: inherit;
}

.cust-toggle-btn.active {
    background: var(--surface-color);
    color: var(--primary-color);
    box-shadow: var(--shadow);
}

/* Dynamic Customer Form sections */
.customer-section {
    display: none;
    animation: checkoutFormFadeIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.customer-section.active {
    display: block;
}

@keyframes checkoutFormFadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}



/* Badges */
.badge { display: inline-block; padding: 0.25rem 0.6rem; font-size: 0.85rem; font-weight: 700; border-radius: 50px; background: #e2e8f0; color: #475569; }
.badge-success { background: rgba(16, 185, 129, 0.15); color: #047857; }
.badge-danger { background: rgba(239, 68, 68, 0.15); color: #b91c1c; }
.badge-primary { background: rgba(79, 70, 229, 0.15); color: #4338ca; }