:root {
    /* App Colors - Dark Mode Premium */
    --bg-main: #0f172a;
    --bg-panel: #1e293b;
    --bg-input: #0f172a;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #6366f1; /* Indigo */
    --accent-hover: #4f46e5;
    --border-color: #334155;
    
    /* Invoice Paper Colors */
    --inv-bg: #ffffff;
    --inv-text: #1e293b;
    --inv-text-light: #64748b;
    --inv-border: #e2e8f0;
    --inv-accent: #6366f1;

    --font-ui: 'Inter', sans-serif;
    --font-heading: 'Outfit', sans-serif;
}

[data-theme="light"] {
    --bg-main: #f8fafc;
    --bg-panel: #ffffff;
    --bg-input: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --border-color: #e2e8f0;
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    overflow-y: auto;
    overflow-x: hidden;
}

/* Layout */
.template-selector-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    background: var(--bg-panel);
    border-bottom: 1px solid var(--border-color);
    height: 60px;
}

.app-container {
    display: flex;
    height: calc(100vh - 60px);
}

.mobile-editor-tabs {
    display: none;
}

.sidebar {
    width: 400px;
    background-color: var(--bg-panel);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
}

.preview-area {
    flex: 1;
    overflow-y: auto;
    padding: 40px;
    display: flex;
    justify-content: center;
    align-items: flex-start;
}

/* Sidebar UI */
.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    background-color: var(--bg-panel);
    z-index: 10;
}

.sidebar-header h2 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 600;
}

.brand-text {
    color: var(--accent-color);
}

.form-container {
    padding: 20px;
}

.form-section {
    margin-bottom: 30px;
    background: var(--bg-panel);
    padding: 20px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.form-section h3 {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    margin-bottom: 15px;
    font-weight: 600;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}
.section-header h3 {
    margin-bottom: 0;
}

/* Form Inputs */
.input-group {
    margin-bottom: 15px;
}

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

label {
    display: block;
    font-size: 0.875rem;
    margin-bottom: 5px;
    color: var(--text-secondary);
}

input, textarea {
    width: 100%;
    padding: 10px 12px;
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: var(--font-ui);
    font-size: 0.875rem;
    transition: all 0.2s;
}

input:focus, textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

textarea {
    resize: vertical;
    min-height: 80px;
}

/* Line Items UI */
.line-item-row {
    display: grid;
    grid-template-columns: 1fr 60px 80px 30px;
    gap: 10px;
    margin-bottom: 10px;
    align-items: start;
    background: var(--bg-main);
    padding: 10px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}
.line-item-row input {
    padding: 8px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: 8px;
    font-family: var(--font-ui);
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
    font-size: 0.875rem;
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-hover) 100%);
    color: white;
    box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background-color: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}
.btn-secondary:hover {
    background-color: var(--border-color);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.8rem;
}

.btn-icon {
    padding: 8px;
    background: transparent;
    color: var(--text-secondary);
    border: none;
}
.btn-icon:hover {
    color: #ef4444; /* red */
}

/* Invoice Paper Preview */
.invoice-paper {
    background-color: var(--inv-bg);
    color: var(--inv-text);
    width: 210mm; /* A4 width */
    min-height: 297mm; /* A4 height */
    padding: 40mm 20mm;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.5);
    border-radius: 4px;
    font-size: 10pt;
    position: relative;
    transform-origin: top center;
}

.preserve-lines {
    white-space: pre-wrap;
}

.invoice-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 40px;
}

.brand-logo {
    font-family: var(--font-heading);
    font-size: 24pt;
    color: var(--inv-accent);
    margin-bottom: 5px;
}

.brand p {
    color: var(--inv-text-light);
    line-height: 1.4;
}

.invoice-title h2 {
    font-family: var(--font-heading);
    font-size: 32pt;
    font-weight: 300;
    letter-spacing: 4px;
    color: var(--inv-border);
}

.invoice-meta-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 40px;
}

.label {
    display: block;
    font-size: 8pt;
    text-transform: uppercase;
    color: var(--inv-text-light);
    letter-spacing: 1px;
    margin-bottom: 4px;
}

.bill-to strong {
    font-size: 12pt;
    display: block;
    margin-bottom: 4px;
}

.meta-details {
    display: flex;
    gap: 30px;
    text-align: right;
}

.meta-item strong {
    font-size: 11pt;
}

.invoice-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 30px;
}

.invoice-table th {
    text-align: left;
    padding: 12px 10px;
    border-bottom: 2px solid var(--inv-accent);
    color: var(--inv-accent);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 8pt;
    letter-spacing: 0.5px;
}

.invoice-table td {
    padding: 15px 10px;
    border-bottom: 1px solid var(--inv-border);
}

.col-desc { width: 50%; }
.col-qty { width: 15%; text-align: center !important; }
.col-rate { width: 15%; text-align: right !important; }
.col-amount { width: 20%; text-align: right !important; }

.invoice-table th.col-qty,
.invoice-table th.col-rate,
.invoice-table th.col-amount {
    text-align: right;
}

.invoice-summary-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 40px;
}

.notes {
    width: 50%;
    color: var(--inv-text-light);
    font-size: 9pt;
}

.totals {
    width: 40%;
}

.total-row {
    display: flex;
    justify-content: space-between;
    padding: 8px 10px;
    border-bottom: 1px solid var(--inv-border);
}

.total-row:last-child {
    border-bottom: none;
}

.grand-total {
    font-weight: 700;
    font-size: 14pt;
    color: var(--inv-accent);
    border-top: 2px solid var(--inv-accent);
    margin-top: 5px;
    padding-top: 15px;
}

}

/* =========================================
   GST Base Templates Styles
   ========================================= */
.gst-details-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 30px;
}
.gst-box {
    border: 1px solid var(--inv-border);
    border-radius: 8px;
    padding: 20px;
    background: #fafafa;
}
.gst-box-title {
    font-size: 8pt;
    text-transform: uppercase;
    color: var(--inv-text-light);
    letter-spacing: 1px;
    margin-bottom: 8px;
    font-weight: 600;
}
.gst-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 30px;
}
.gst-table th {
    text-align: left;
    padding: 12px 10px;
    border-bottom: 2px solid var(--inv-accent);
    color: var(--inv-accent);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 8pt;
    letter-spacing: 0.5px;
}
.gst-table td {
    padding: 12px 10px;
    border-bottom: 1px solid var(--inv-border);
    font-size: 9.5pt;
}
.gst-table .text-center {
    text-align: center;
}
.gst-table .text-right {
    text-align: right;
}

/* =========================================
   INVOICE THEMES (CSS-Based Templates)
   ========================================= */

/* 1. Minimalist Clean */
.theme-minimalist .invoice-paper {
    font-family: 'Georgia', serif;
    color: #222;
}
.theme-minimalist .inline-input {
    font-family: 'Georgia', serif;
}
.theme-minimalist #gstInvoiceTitle {
    font-size: 2.5rem;
    font-weight: 400;
    letter-spacing: 2px;
}
.theme-minimalist .gst-box {
    background: transparent;
    border: none;
    border-top: 1px solid #ddd;
    border-radius: 0;
    padding: 15px 0;
}
.theme-minimalist .gst-box-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: #888;
}
.theme-minimalist .gst-table th {
    border-top: 1px solid #222;
    border-bottom: 1px solid #222;
    color: #222;
    background: transparent;
}
.theme-minimalist .gst-table td {
    border-bottom: 1px dashed #eee;
}

/* 2. Corporate Formal */
.theme-corporate .invoice-paper {
    font-family: 'Inter', sans-serif;
}
.theme-corporate #gstInvoiceTitle {
    color: var(--inv-accent);
    font-weight: 700;
}
.theme-corporate .gst-details-grid {
    gap: 0;
}
.theme-corporate .gst-box {
    border: 1px solid var(--inv-border);
    border-radius: 0;
    background: #fafafa;
}
.theme-corporate .gst-table {
    border: 1px solid var(--inv-border);
}
.theme-corporate .gst-table th {
    background-color: var(--inv-accent);
    color: white;
    border: 1px solid var(--inv-accent);
}
.theme-corporate .gst-table td {
    border-left: 1px solid var(--inv-border);
    border-right: 1px solid var(--inv-border);
}

/* 3. Vibrant Creative */
.theme-vibrant .invoice-paper {
    background: linear-gradient(135deg, #ffffff 0%, #f9faff 100%);
    font-family: 'Outfit', sans-serif;
}
.theme-vibrant #gstInvoiceTitle {
    color: var(--inv-accent);
    font-size: 3rem;
    font-weight: 800;
}
.theme-vibrant .gst-box {
    border-radius: 16px;
    border: 2px solid var(--inv-accent);
    background: white;
    box-shadow: 0 4px 15px rgba(0,0,0,0.03);
}
.theme-vibrant .gst-box-title {
    color: var(--inv-accent);
    font-weight: 700;
}
.theme-vibrant .gst-table th {
    color: var(--inv-accent);
    border-bottom: 3px solid var(--inv-accent);
}

/* 4. Dark Mode Native */
.theme-dark-export .invoice-paper {
    background-color: #121212 !important;
    color: #e0e0e0 !important;
}
.theme-dark-export .inline-input {
    color: #e0e0e0 !important;
}
.theme-dark-export .inline-input:focus {
    background: rgba(255,255,255,0.05);
}
.theme-dark-export #gstInvoiceTitle {
    color: #fff;
}
.theme-dark-export .gst-box {
    background-color: #1e1e1e !important;
    border: 1px solid #333 !important;
}
.theme-dark-export .gst-table th {
    color: var(--inv-accent);
    border-bottom: 2px solid #333 !important;
}
.theme-dark-export .gst-table td {
    border-bottom: 1px solid #2a2a2a !important;
}
.theme-dark-export .gst-box-title {
    color: #aaa !important;
}

/* Print Specific Rules for Dark Export to force backgrounds */
@media print {
    .theme-dark-export .invoice-paper {
        background-color: #121212 !important;
        -webkit-print-color-adjust: exact;
        print-color-adjust: exact;
    }
    .theme-dark-export .gst-box {
        background-color: #1e1e1e !important;
        -webkit-print-color-adjust: exact;
        print-color-adjust: exact;
    }
    .theme-dark-export .inline-input {
        color: #fff !important;
    }
    .theme-dark-export .invoice-footer {
        color: #888 !important;
    }
}
/* ========================================= */

/* Print CSS */
@media print {
    * {
        -webkit-print-color-adjust: exact !important;
        print-color-adjust: exact !important;
    }
    body {
        background-color: white !important;
        color: black;
        height: auto;
        overflow: visible !important;
    }
    .no-print {
        display: none !important;
    }
    .app-container {
        display: block !important;
        height: auto !important;
    }
    .preview-area {
        padding: 0 !important;
        display: block !important;
        overflow: visible !important;
        height: auto !important;
    }
    #classicTemplateContainer,
    #gstTemplateContainer,
    .gst-template-wrapper {
        display: block !important;
        overflow: visible !important;
        width: 100% !important;
        transform: none !important;
        box-shadow: none !important;
        margin: 0 !important;
        padding: 0 !important;
    }
    .invoice-paper {
        box-shadow: none !important;
        margin: 0 !important;
        padding: 0 !important;
        width: 100% !important;
        min-height: auto !important;
        transform: none !important;
    }
    @page {
        size: A4;
        margin: 15mm;
    }
    .hide-on-print {
        display: none !important;
    }
}

/* Responsiveness for App (not print) */
@media screen and (max-width: 1024px) {
    .app-container {
        flex-direction: column;
        overflow: auto;
        height: auto; /* Allow full height on mobile/tablet */
    }
    .sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        overflow: visible;
    }
    .preview-area {
        overflow: auto;
    }
    .invoice-paper {
        width: 800px !important;
        margin: 0 auto 30px auto !important;
    }
}

@media screen and (max-width: 768px) {
    .grid-2, .form-grid {
        grid-template-columns: 1fr !important;
    }
    
    /* Top template bar mobile styling */
    .template-selector-bar {
        flex-direction: column !important;
        gap: 12px !important;
        height: auto !important;
        align-items: stretch !important;
        padding: 12px 15px !important;
    }
    .template-selector-bar > div {
        width: 100% !important;
        display: flex !important;
        justify-content: space-between !important;
        align-items: center !important;
    }
    .template-selector-bar select {
        width: calc(100% - 130px) !important;
        max-width: 220px;
    }

    .header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }
    .header > div {
        flex-direction: column;
        width: 100%;
    }
    .header > div > button {
        width: 100%;
        justify-content: center;
    }
    .dashboard-controls {
        flex-direction: column;
        align-items: flex-start;
    }
    .dashboard-controls a.btn {
        width: 100%;
        justify-content: center;
    }
    .table-responsive {
        width: 100%;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
    .data-table {
        min-width: 600px;
    }
    
    /* Mobile Editor Navigation Tabs */
    .mobile-editor-tabs {
        display: flex !important;
        width: 100% !important;
        background: var(--bg-panel);
        border-bottom: 1px solid var(--border-color);
        position: sticky;
        top: 0;
        z-index: 100;
    }
    .mobile-tab-btn {
        flex: 1;
        padding: 14px;
        background: transparent;
        border: none;
        color: var(--text-secondary);
        font-family: var(--font-ui);
        font-weight: 600;
        font-size: 0.9rem;
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 8px;
        border-bottom: 2px solid transparent;
        transition: all 0.2s ease;
    }
    .mobile-tab-btn.active {
        color: var(--accent-color);
        border-bottom-color: var(--accent-color);
        background: rgba(99, 102, 241, 0.03);
    }
    
    /* Responsive layout structure for editor on mobile viewports */
    .app-container {
        flex-direction: column !important;
        height: calc(100vh - 60px) !important;
        position: relative;
    }
    .sidebar {
        display: block !important;
        width: 100% !important;
        height: calc(100vh - 110px) !important;
        overflow-y: auto !important;
    }
    .preview-area {
        display: none !important;
        width: 100% !important;
        height: calc(100vh - 110px) !important;
    }

    /* JavaScript Toggle Classes for Mobile */
    .sidebar.mobile-hidden {
        display: none !important;
    }
    .preview-area.mobile-shown {
        display: block !important;
        padding: 15px !important;
        overflow-x: auto !important;
        overflow-y: auto !important;
        background: rgba(0,0,0,0.1);
        -webkit-overflow-scrolling: touch;
    }

    .invoice-paper {
        width: 800px !important;
        margin: 0 auto 30px auto !important;
    }
    .gst-template-wrapper {
        overflow: visible !important;
        padding: 0 !important;
    }
    .gst-template-wrapper .invoice-paper {
        min-width: 800px !important;
        width: 800px !important;
    }
}

/* Landscape Phone Orientation Optimizations */
@media (orientation: landscape) and (max-height: 520px) {
    .mobile-editor-tabs {
        display: none !important;
    }
    .app-container {
        flex-direction: row !important;
        height: calc(100vh - 50px) !important;
        overflow: hidden !important;
    }
    .template-selector-bar {
        flex-direction: row !important;
        height: 50px !important;
        padding: 5px 15px !important;
        gap: 10px !important;
    }
    .template-selector-bar select {
        width: 150px !important;
        padding: 4px 8px !important;
    }
    .sidebar, .sidebar.mobile-hidden {
        display: block !important;
        width: 300px !important;
        border-right: 1px solid var(--border-color) !important;
        border-bottom: none !important;
        height: 100% !important;
        overflow-y: auto !important;
    }
    .preview-area, .preview-area.mobile-shown {
        display: flex !important;
        flex: 1 !important;
        width: auto !important;
        height: 100% !important;
        overflow-x: hidden !important;
        overflow-y: auto !important;
        padding: 10px !important;
        justify-content: center !important;
        align-items: flex-start !important;
        background: rgba(0,0,0,0.15);
    }
    .invoice-paper {
        transform: scale(0.45); /* Fallback scale */
        transform-origin: top center;
        width: 800px !important;
        margin: 0 auto !important;
    }
    .sidebar-header {
        padding: 10px 15px !important;
    }
    .sidebar-header h2 {
        font-size: 1.1rem !important;
    }
    .form-container {
        padding: 10px 15px !important;
    }
    .form-section {
        margin-bottom: 15px !important;
        padding: 12px !important;
    }
}