:root {
            --bg-color: #14160f;
            --panel-bg: #1b1e16;
            --card-bg: #1b1e16;
            --card-border: #383c2e;
            --card-border-strong: #4c5140;
            --primary: #e2792c;
            --primary-glow: rgba(226, 121, 44, 0.16);
            --secondary: #7f9baf;
            --secondary-glow: rgba(127, 155, 175, 0.16);
            --accent: #c9a13b;
            --success: #7fb069;
            --warning: #e8b339;
            --danger: #d9615c;
            --ply-0: #7f9baf;
            --ply-45: #e2792c;
            --ply-n45: #c9a13b;
            --ply-90: #7fb069;
            --ply-other: #b8735a;
            --text: #edf0e4;
            --text-muted: #9a9d8a;
            --text-faint: #6d705f;
            --billing-active-color: #ffffff;
            --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
            --font-mono: ui-monospace, 'JetBrains Mono', 'SFMono-Regular', Menlo, Consolas, 'Liberation Mono', monospace;
        }

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

        body {
            background-color: var(--bg-color);
            background-image:
                repeating-linear-gradient(45deg, rgba(255, 255, 255, 0.012) 0px, rgba(255, 255, 255, 0.012) 1px, transparent 1px, transparent 5px),
                repeating-linear-gradient(-45deg, rgba(0, 0, 0, 0.14) 0px, rgba(0, 0, 0, 0.14) 1px, transparent 1px, transparent 5px);
            background-attachment: fixed;
            color: var(--text);
            font-family: var(--font-sans);
            min-height: 100vh;
            padding: 1.5rem;
            line-height: 1.5;
        }

        .container {
            width: 100%;
            max-width: 1400px;
            margin: 0 auto;
        }

        header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 2rem;
            padding-bottom: 1rem;
            border-bottom: 1px solid var(--card-border);
        }

        .logo-area h1 {
            font-family: var(--font-mono);
            font-size: 1.5rem;
            font-weight: 700;
            letter-spacing: 0.01em;
            color: var(--text);
            border-bottom: 2px solid var(--primary);
            display: inline-block;
            padding-bottom: 0.3rem;
        }

        .logo-area p {
            font-family: var(--font-mono);
            font-size: 0.72rem;
            letter-spacing: 0.03em;
            color: var(--text-faint);
            text-transform: uppercase;
            margin-top: 0.5rem;
        }

        .nav-links a {
            color: var(--text-muted);
            text-decoration: none;
            font-size: 0.95rem;
            transition: color 0.2s;
            margin-left: 1.5rem;
        }

        .nav-links a:hover {
            color: var(--primary);
        }

        .grid {
            display: grid;
            grid-template-columns: 350px 1fr;
            gap: 1.5rem;
            width: 100%;
        }

        .sidebar, .main-panel {
            min-width: 0;
            overflow: hidden;
            width: 100%;
        }

        .eng-constants-grid {
            grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
        }

        @media (max-width: 1024px) {
            .grid {
                grid-template-columns: 1fr;
            }
        }

        @media (max-width: 768px) {
            body {
                padding: 0.75rem;
            }

            header {
                flex-direction: column;
                gap: 1rem;
                text-align: center;
                align-items: center;
                padding-bottom: 1.25rem;
            }

            .logo-area {
                margin-bottom: 0.25rem;
            }

            .nav-links {
                display: flex;
                flex-wrap: wrap;
                justify-content: center;
                align-items: center;
                gap: 0.75rem;
            }

            .nav-links a {
                margin-left: 0;
                padding: 0.25rem 0.5rem;
            }

            .summary-grid {
                grid-template-columns: repeat(2, 1fr) !important;
                gap: 0.75rem;
            }

            .matrix-container {
                grid-template-columns: 1fr !important;
                gap: 1rem;
            }

            .visualization-pane {
                grid-template-columns: 1fr !important;
                gap: 1.5rem !important;
            }

            .stack-diagram-title-container {
                margin-bottom: 1rem !important;
                height: auto !important;
            }



            .ply-bar {
                font-size: 0.65rem !important;
            }

            .tabs {
                flex-direction: column;
                align-items: stretch;
                white-space: normal;
                overflow-x: visible;
                border-bottom: none;
                gap: 0.5rem;
            }

            .tab-btn {
                text-align: left;
                width: 100%;
                border-bottom: none !important;
                border-left: 3px solid transparent;
                background: rgba(255, 255, 255, 0.02);
                border-radius: 2px;
                padding: 0.75rem 1rem;
            }

            .tab-btn.active {
                border-left: 3px solid var(--primary);
                background: var(--primary-glow);
                color: var(--primary);
            }

            .optimization-settings-container {
                grid-template-columns: 1fr !important;
            }

            .pricing-grid {
                grid-template-columns: 1fr !important;
                gap: 1.25rem;
            }

            .pricing-modal {
                padding: 1.5rem !important;
                width: 95% !important;
                max-height: 90vh;
                overflow-y: auto;
            }

            .input-row, .input-row-3 {
                grid-template-columns: 1fr !important;
                gap: 0.5rem;
            }

            .config-buttons {
                flex-direction: column;
            }

            .eng-constants-grid {
                grid-template-columns: repeat(2, 1fr) !important;
            }

            #ply-table {
                min-width: 900px;
            }

            #ply-editor-table {
                min-width: 550px;
            }
        }

        @media (max-width: 480px) {
            .card {
                padding: 1rem;
            }

            .card-title {
                font-size: 0.9rem;
                margin-bottom: 1rem;
            }

            .logo-area h1 {
                font-size: 1.15rem;
            }

            .matrix-grid {
                font-size: 0.7rem !important;
                gap: 0.2rem !important;
            }
            .matrix-val {
                padding: 0.2rem 0.3rem !important;
            }

            #polarPropertiesChart {
                max-width: 100% !important;
                max-height: 280px !important;
            }

            .chart-container {
                height: auto !important;
                padding: 0.5rem !important;
            }
        }

        /* Flat instrument-panel card styling */
        .card {
            background: var(--card-bg);
            border: 1px solid var(--card-border);
            border-radius: 3px;
            padding: 1.5rem;
            transition: border-color 0.2s;
        }

        .card-title {
            font-family: var(--font-mono);
            font-size: 1rem;
            font-weight: 700;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            margin-bottom: 1.2rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 0.5rem;
            color: var(--text);
            border-left: 3px solid var(--primary);
            padding-left: 8px;
            overflow-wrap: break-word;
            word-break: break-word;
        }

        /* Forms and inputs */
        .form-group {
            margin-bottom: 1rem;
        }

        label {
            display: block;
            font-size: 0.85rem;
            font-weight: 500;
            color: var(--text-muted);
            margin-bottom: 0.35rem;
        }

        .input-row {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 0.75rem;
        }

        .input-row-3 {
            display: grid;
            grid-template-columns: 1fr 1fr 1fr;
            gap: 0.5rem;
        }

        input, select {
            width: 100%;
            background: rgba(255, 255, 255, 0.04);
            border: 1px solid var(--card-border);
            border-radius: 2px;
            color: var(--text);
            padding: 0.55rem 0.75rem;
            font-size: 0.9rem;
            font-family: var(--font-mono);
            font-variant-numeric: tabular-nums;
            transition: border-color 0.2s, box-shadow 0.2s;
        }

        input:focus, select:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 1px var(--primary);
        }

        /* Optimizer Candidate Material Selection Styles */
        .opt-material-selection-container {
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
            background: rgba(0, 0, 0, 0.2);
            padding: 0.75rem;
            border-radius: 2px;
            border: 1px solid var(--card-border);
            margin-top: 0.5rem;
        }

        .opt-mat-row {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 0.75rem;
            padding: 0.5rem 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.05);
        }

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

        .opt-mat-label {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            font-size: 0.85rem;
            font-weight: 500;
            margin: 0;
            cursor: pointer;
            color: var(--text);
            flex: 1;
            min-width: 0;
        }

        .opt-mat-label input[type="checkbox"] {
            width: 1.1rem;
            height: 1.1rem;
            margin: 0;
            cursor: pointer;
            accent-color: var(--primary);
            flex-shrink: 0;
        }

        .opt-mat-label span {
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .opt-mat-controls {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            flex-shrink: 0;
        }

        .opt-mat-controls select.opt-mat-mode {
            padding: 0.35rem 0.5rem;
            font-size: 0.8rem;
            background: rgba(255, 255, 255, 0.04);
            border: 1px solid var(--card-border);
            color: var(--text);
            border-radius: 2px;
            width: 95px;
            height: 32px;
            cursor: pointer;
            transition: border-color 0.2s, box-shadow 0.2s;
        }

        .opt-mat-controls input.opt-mat-val {
            padding: 0.35rem 0.5rem;
            font-size: 0.8rem;
            width: 115px;
            height: 32px;
            border-radius: 2px;
            background: rgba(255, 255, 255, 0.04);
            border: 1px solid var(--card-border);
            color: var(--text);
            text-align: center;
            transition: border-color 0.2s, box-shadow 0.2s;
        }

        .opt-mat-controls select.opt-mat-mode:focus,
        .opt-mat-controls input.opt-mat-val:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 1px var(--primary);
        }

        /* Responsive styling for smaller devices */
        @media (max-width: 480px) {
            .opt-mat-row {
                flex-direction: column;
                align-items: stretch;
                gap: 0.5rem;
                padding: 0.75rem 0;
            }

            .opt-mat-label {
                width: 100%;
            }

            .opt-mat-controls {
                width: 100%;
                justify-content: space-between;
                gap: 0.5rem;
            }

            .opt-mat-controls select.opt-mat-mode {
                flex: 1;
                max-width: none;
                width: auto;
            }

            .opt-mat-controls input.opt-mat-val {
                flex: 1.5;
                max-width: none;
                width: auto;
            }
        }

        .btn {
            display: inline-flex;
            justify-content: center;
            align-items: center;
            width: 100%;
            background: var(--primary);
            color: #14160f;
            border: 1px solid var(--primary);
            border-radius: 2px;
            padding: 0.75rem;
            font-size: 0.9rem;
            font-weight: 700;
            letter-spacing: 0.01em;
            cursor: pointer;
            transition: background 0.15s, border-color 0.15s, transform 0.1s;
        }

        .btn:hover {
            background: #f08c42;
            border-color: #f08c42;
        }

        .btn:active {
            transform: scale(0.98);
        }

        .btn-secondary {
            background: rgba(255, 255, 255, 0.05);
            color: var(--text);
            border: 1px solid var(--card-border-strong);
        }

        .btn-secondary:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        .btn-accent {
            background: var(--secondary);
            border-color: var(--secondary);
            color: #14160f;
        }

        .btn-accent:hover {
            background: #9db6c8;
            border-color: #9db6c8;
        }

        .preset-buttons {
            display: flex;
            gap: 0.5rem;
            margin-bottom: 1rem;
        }

        .preset-btn {
            flex: 1;
            padding: 0.35rem;
            font-size: 0.75rem;
            border-radius: 2px;
        }

        /* Tabs styling */
        .tabs {
            display: flex;
            border-bottom: 1px solid var(--card-border);
            margin-bottom: 1.5rem;
            gap: 1rem;
        }

        .tab-btn {
            background: none;
            border: none;
            color: var(--text-faint);
            font-family: var(--font-mono);
            font-size: 0.82rem;
            font-weight: 600;
            letter-spacing: 0.02em;
            padding: 0.5rem 1rem;
            cursor: pointer;
            transition: color 0.2s, border-color 0.2s;
            border-bottom: 2px solid transparent;
        }

        .tab-btn:hover {
            color: var(--text);
        }

        .tab-btn.active {
            color: var(--primary);
            border-bottom-color: var(--primary);
        }

        .tab-content {
            display: none;
        }

        .tab-content.active {
            display: block;
        }

        /* Matrices and Tables */
        .matrix-container {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 1rem;
            margin-bottom: 1.5rem;
        }

        .matrix-card {
            background: rgba(0, 0, 0, 0.18);
            border: 1px solid var(--card-border);
            border-radius: 2px;
            padding: 1rem;
            font-family: var(--font-mono);
        }

        .matrix-title {
            font-size: 0.75rem;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            color: var(--text-faint);
            margin-bottom: 0.5rem;
            font-weight: 600;
            text-align: center;
        }

        .matrix-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 0.35rem;
            text-align: right;
            font-size: 0.8rem;
        }

        .matrix-val {
            background: rgba(0, 0, 0, 0.22);
            padding: 0.35rem 0.5rem;
            border-radius: 2px;
            color: var(--secondary);
            font-variant-numeric: tabular-nums;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .table-responsive {
            width: 100%;
            overflow-x: auto;
            border-radius: 2px;
            border: 1px solid var(--card-border);
            margin-bottom: 1.5rem;
        }

        table {
            width: 100%;
            border-collapse: collapse;
            text-align: left;
            font-size: 0.85rem;
        }

        th {
            background: rgba(255, 255, 255, 0.03);
            color: var(--text-faint);
            font-family: var(--font-mono);
            font-size: 0.72rem;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            font-weight: 600;
            padding: 0.75rem 1rem;
            border-bottom: 1px solid var(--card-border);
        }

        td {
            padding: 0.75rem 1rem;
            border-bottom: 1px solid rgba(255, 255, 255, 0.03);
            font-family: var(--font-mono);
            font-variant-numeric: tabular-nums;
        }

        tr:hover {
            background: rgba(255, 255, 255, 0.02);
        }

        /* Ply stack visualization */
        .visualization-pane {
            display: grid;
            grid-template-columns: 200px 1fr;
            gap: 1.5rem;
            align-items: start;
        }

        .stack-diagram-title-container {
            display: flex;
            height: 38px;
            align-items: center;
            margin-bottom: 1rem;
        }

        .ply-stack-diagram {
            display: flex;
            flex-direction: column;
            border: 1px solid var(--card-border);
            border-radius: 2px;
            padding: 10px;
            background: rgba(0, 0, 0, 0.2);
            height: auto;
            justify-content: stretch;
            gap: 0;
            box-sizing: border-box;
        }

        .ply-bar {
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            border-radius: 1px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-family: var(--font-mono);
            font-size: 0.75rem;
            font-weight: 700;
            color: #14160f;
	    margin: 1px 0px;
            transition: all 0.3s;
        }


        /* Badges */
        .badge {
            display: inline-flex;
            align-items: center;
            gap: 0.4em;
            padding: 0.2rem 0.55rem;
            border-radius: 2px;
            font-family: var(--font-mono);
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.04em;
            text-transform: uppercase;
        }

        .badge::before {
            content: "";
            width: 0.5em;
            height: 0.5em;
            background: currentColor;
            flex-shrink: 0;
        }

        .badge-success {
            background: rgba(127, 176, 105, 0.12);
            color: var(--success);
            border: 1px solid rgba(127, 176, 105, 0.4);
        }

        .badge-danger {
            background: rgba(217, 97, 92, 0.12);
            color: var(--danger);
            border: 1px solid rgba(217, 97, 92, 0.4);
        }

        .badge-warning {
            background: rgba(232, 179, 57, 0.12);
            color: var(--warning);
            border: 1px solid rgba(232, 179, 57, 0.4);
        }

        /* Summary boxes */
        .summary-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 1px;
            background: var(--card-border);
            border: 1px solid var(--card-border);
            margin-bottom: 1.5rem;
        }

        .summary-card {
            background: var(--card-bg);
            border: none;
            border-radius: 0;
            padding: 1rem;
            text-align: center;
        }

        .summary-val {
            font-family: var(--font-mono);
            font-variant-numeric: tabular-nums;
            font-size: 1.4rem;
            font-weight: 700;
            color: var(--text);
            margin-bottom: 0.25rem;
        }

        .summary-label {
            font-family: var(--font-mono);
            font-size: 0.68rem;
            color: var(--text-faint);
            text-transform: uppercase;
            letter-spacing: 0.06em;
        }

        .chart-container {
            position: relative;
            height: 320px;
            width: 100%;
            margin-bottom: 1.5rem;
            background: rgba(0, 0, 0, 0.14);
            border-radius: 2px;
            padding: 1rem;
            border: 1px solid var(--card-border);
            overflow: hidden;
        }

        .chart-wrapper {
            height: 100%;
            position: relative;
            width: 100%;
        }

        #distributionChartWrapper {
            height: 100%;
        }

        @media (max-width: 768px) {
            .chart-container {
                overflow-x: auto;
            }
            #distributionChartWrapper {
                min-width: 700px;
            }
            .weibull-chart-wrapper {
                min-width: 450px;
            }
        }

        .chart-filter-group {
            margin: 0;
            width: 150px;
        }
        @media (max-width: 600px) {
            .chart-filter-group {
                flex: 1 1 calc(33.333% - 0.5rem);
                min-width: 90px;
            }
        }
        @media (max-width: 400px) {
            .chart-filter-group {
                flex: 1 1 100%;
            }
        }

        .loading-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100vw;
            height: 100vh;
            background: rgba(20, 22, 15, 0.9);
            backdrop-filter: blur(6px);
            z-index: 1000;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            opacity: 0;
            pointer-events: none;
            transition: opacity 0.3s;
        }

        .loading-overlay.active {
            opacity: 1;
            pointer-events: auto;
        }

        .spinner {
            width: 50px;
            height: 50px;
            border: 4px solid rgba(226, 121, 44, 0.15);
            border-top-color: var(--primary);
            border-radius: 50%;
            animation: spin 1s linear infinite;
            margin-bottom: 1rem;
        }

        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }

        .console {
            background: #0e0f0a;
            border: 1px solid var(--card-border);
            border-radius: 2px;
            padding: 1rem;
            font-family: var(--font-mono);
            font-size: 0.8rem;
            max-height: 150px;
            overflow-y: auto;
            color: var(--success);
            margin-top: 1rem;
        }

        .console-entry {
            margin-bottom: 0.25rem;
        }

        .console-entry.error {
            color: var(--danger);
        }

        .console-entry.warning {
            color: var(--warning);
        }

        .console-entry.info {
            color: var(--secondary);
        }

        /* Pricing Modal & Badges */
        .badge-free { color: var(--text-muted); background: rgba(255, 255, 255, 0.05); border: 1px solid var(--card-border); }
        .badge-researcher { color: var(--warning); background: rgba(232, 179, 57, 0.1); border-color: rgba(232, 179, 57, 0.35) !important; }
        .badge-professional { color: var(--secondary); background: rgba(127, 155, 175, 0.1); border-color: rgba(127, 155, 175, 0.35) !important; }

        .modal-backdrop {
            position: fixed;
            top: 0; left: 0; right: 0; bottom: 0;
            background: rgba(20, 22, 15, 0.9);
            backdrop-filter: blur(6px);
            z-index: 1000;
            display: flex;
            justify-content: center;
            align-items: center;
            opacity: 0;
            pointer-events: none;
            transition: opacity 0.3s;
        }
        .modal-backdrop.active {
            opacity: 1;
            pointer-events: auto;
        }
        .pricing-modal {
            background: var(--panel-bg);
            border: 1px solid var(--card-border-strong);
            border-radius: 3px;
            width: 90%;
            max-width: 850px;
            max-height: 90vh;
            overflow-y: auto;
            padding: 10px;
            box-shadow: 0 20px 40px -12px rgba(0, 0, 0, 0.55);
            position: relative;
            transform: scale(0.97);
            transition: transform 0.3s;
        }
        .modal-backdrop.active .pricing-modal {
            transform: scale(1);
        }
        .modal-close {
            position: absolute;
            top: 1.25rem; right: 1.25rem;
            background: none; border: none;
            color: var(--text-muted); font-size: 1.5rem;
            cursor: pointer;
        }
        .modal-close:hover { color: var(--text); }

        .optimization-settings-container {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 1.5rem;
            margin-bottom: 1.5rem;
        }
        .optimization-settings-container.deterministic-only {
            grid-template-columns: 1fr;
        }

        .pricing-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 1.5rem;
            margin-top: 1rem;
            margin-bottom: 1rem;
        }
        .pricing-card {
            background: rgba(255, 255, 255, 0.015);
            border: 1px solid var(--card-border);
            border-radius: 3px;
            padding: 1.5rem;
            display: flex;
            flex-direction: column;
            position: relative;
            overflow: hidden;
            transition: border-color 0.2s;
        }
        .pricing-card:hover {
            border-color: var(--card-border-strong);
        }
        .pricing-card.popular {
            border-color: var(--primary);
            background: var(--primary-glow);
        }
        .pricing-card.popular::before {
            content: "POPULAR";
            position: absolute;
            top: 12px; right: -24px;
            background: var(--primary);
            color: #14160f;
            font-family: var(--font-mono);
            font-size: 0.62rem;
            font-weight: 700;
            letter-spacing: 0.04em;
            padding: 0.25rem 1.5rem;
            transform: rotate(45deg);
        }
        .price-title { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.5rem; }
        .price-val { font-family: var(--font-mono); font-size: 1.75rem; font-weight: 700; color: var(--text); margin-bottom: 1rem; }
        .price-val span { font-size: 0.85rem; font-weight: 400; color: var(--text-muted); }
        .price-features {
            list-style: none; padding: 0; margin: 0 0 1.5rem 0;
            font-size: 0.85rem; color: var(--text-muted);
            flex-grow: 1;
        }
        .price-features li { margin-bottom: 0.5rem; display: flex; align-items: center; gap: 0.5rem; }
        .price-features li::before { content: "✓"; color: var(--success); font-weight: bold; }
        .price-btn {
            background: rgba(255, 255, 255, 0.06);
            border: 1px solid var(--card-border-strong);
            color: var(--text);
            font-weight: 600;
            padding: 0.6rem;
            border-radius: 2px;
            cursor: pointer;
            width: 100%;
            transition: background 0.2s, border-color 0.2s;
        }
        .price-btn:hover { background: var(--primary); border-color: var(--primary); color: #14160f; }
        .pricing-card.popular .price-btn { background: var(--primary); border-color: var(--primary); color: #14160f; }
        .pricing-card.popular .price-btn:hover { background: #f08c42; border-color: #f08c42; }

        .api-key-input-section {
            background: rgba(255, 255, 255, 0.015);
            border: 1px solid var(--card-border);
            border-radius: 2px;
            padding: 1.25rem;
            display: flex;
            flex-direction: row;
            gap: 1rem;
            align-items: center;
            justify-content: space-between;
        }
        .api-key-label {
            font-size: 0.85rem;
            color: var(--text-muted);
            font-weight: 500;
            white-space: nowrap;
            flex-shrink: 0;
        }
        .api-key-input-section input {
            flex: 1;
            min-width: 0;
            width: auto;
            box-sizing: border-box;
            background: var(--bg-color);
            border: 1px solid var(--card-border);
            color: var(--text);
            padding: 0.6rem;
            border-radius: 2px;
            font-family: var(--font-mono);
            font-size: 0.85rem;
        }
        .api-key-buttons {
            display: flex;
            gap: 0.75rem;
            flex-shrink: 0;
        }

        @media (max-width: 768px) {
            .api-key-input-section {
                flex-direction: column;
                align-items: stretch;
                text-align: center;
                gap: 0.75rem;
            }
            .api-key-label {
                display: block;
                text-align: center;
                white-space: normal;
            }
            .api-key-input-section input {
                width: 100%;
                text-align: center;
            }
            .api-key-buttons {
                justify-content: center;
                margin-top: 0.25rem;
            }
        }

/* Slider toggle switch styling */
.switch input:checked + .slider {
    background-color: var(--primary) !important;
}
.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    transition: .3s;
}
.slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    border-radius: 50%;
    transition: .3s;
}
.switch input:checked + .slider:before {
    transform: translateX(22px);
}

/* Light Theme Variables and Class Overrides */
:root.light-theme {
    --bg-color: #f2f0e8;
    --panel-bg: #fbfaf5;
    --card-bg: #fbfaf5;
    --card-border: #ddd8c7;
    --card-border-strong: #c7c1ac;
    --primary: #b45309;
    --primary-glow: rgba(180, 83, 9, 0.08);
    --secondary: #3d6178;
    --secondary-glow: rgba(61, 97, 120, 0.08);
    --accent: #8a6a1a;
    --success: #4d7c3f;
    --warning: #b45309;
    --danger: #b3413c;
    --text: #23241c;
    --text-muted: #5c5e50;
    --text-faint: #83866f;
    --billing-active-color: var(--text);
}

:root.light-theme body {
    background-image:
        repeating-linear-gradient(45deg, rgba(0, 0, 0, 0.012) 0px, rgba(0, 0, 0, 0.012) 1px, transparent 1px, transparent 5px),
        repeating-linear-gradient(-45deg, rgba(0, 0, 0, 0.02) 0px, rgba(0, 0, 0, 0.02) 1px, transparent 1px, transparent 5px);
    color: var(--text);
}

:root.light-theme .card,
:root.light-theme .glass-panel,
:root.light-theme .pricing-modal,
:root.light-theme .modal-content {
    background: var(--panel-bg);
    box-shadow: none;
    border: 1px solid var(--card-border);
}

:root.light-theme input,
:root.light-theme select,
:root.light-theme textarea {
    background: #ffffff !important;
    color: var(--text) !important;
    border: 1px solid var(--card-border-strong) !important;
}

:root.light-theme input::placeholder {
    color: var(--text-faint);
}

:root.light-theme .console {
    background: #ffffff;
    border: 1px solid var(--card-border);
    color: #2d5c22;
}

:root.light-theme .console-entry.info {
    color: var(--secondary);
}

:root.light-theme .api-key-input-section input {
    background: #ffffff !important;
    color: var(--text) !important;
    border: 1px solid var(--card-border-strong) !important;
}

:root.light-theme #signed-in-user-info {
    background: var(--primary-glow) !important;
    border-color: rgba(180, 83, 9, 0.2) !important;
    color: var(--primary) !important;
}

:root.light-theme #plan-change-warning-banner {
    background: rgba(180, 83, 9, 0.06) !important;
    border-color: rgba(180, 83, 9, 0.2) !important;
    color: #8a3f07 !important;
}

:root.light-theme .logo-area h1 {
    color: var(--text);
    border-bottom-color: var(--primary);
}

:root.light-theme .badge-free {
    background: rgba(0, 0, 0, 0.04);
    color: var(--text);
}

:root.light-theme .slider {
    background-color: rgba(0, 0, 0, 0.1) !important;
}

:root.light-theme .price-btn {
    color: var(--text) !important;
    background: rgba(0, 0, 0, 0.04) !important;
    border-color: var(--card-border) !important;
}

:root.light-theme .tab-btn:hover {
    color: var(--primary) !important;
}

:root.light-theme .btn-secondary {
    color: var(--text) !important;
    background: rgba(0, 0, 0, 0.04) !important;
    border-color: var(--card-border-strong) !important;
}

:root.light-theme .btn-secondary:hover {
    background: rgba(0, 0, 0, 0.08) !important;
    color: var(--text) !important;
}

:root.light-theme .chart-container {
    background: #ffffff !important;
    border: 1px solid var(--card-border) !important;
}

:root.light-theme [style*="color: #fff"]:not(.btn),
:root.light-theme [style*="color:#fff"]:not(.btn),
:root.light-theme [style*="color: white"]:not(.btn),
:root.light-theme [style*="color:white"]:not(.btn) {
    color: var(--text) !important;
}

/* Light theme overrides for candidate materials in optimizer */
:root.light-theme .opt-material-selection-container {
    background: rgba(0, 0, 0, 0.025);
}

:root.light-theme .opt-mat-row {
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

:root.light-theme .opt-mat-controls select.opt-mat-mode,
:root.light-theme .opt-mat-controls input.opt-mat-val {
    background: #ffffff !important;
    color: var(--text) !important;
    border: 1px solid var(--card-border-strong) !important;
}