 <style>
        /* ─── RESET & ROOT ─── */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        :root {
            --bg: #f6f9fc;
            --card: #ffffff;
            --primary: #1a3b5d;
            --accent: #0d6efd;
            --text: #1e293b;
            --subtext: #475569;
            --border: #dce3ed;
            --shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
            --radius: 16px;
            --transition: 0.2s ease;
        }
        body {
            font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
            background: var(--bg);
            color: var(--text);
            line-height: 1.6;
            padding: 0;
            margin: 0;
        }
        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* ─── HEADER ─── */
        .sdh-header {
            background: var(--primary);
            color: #fff;
            padding: 14px 0;
            box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
            position: sticky;
            top: 0;
            z-index: 100;
        }
        .sdh-header .container {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            gap: 12px;
        }
        .sdh-brand {
            display: flex;
            align-items: center;
            gap: 8px;
            text-decoration: none;
            color: #fff;
            font-weight: 700;
            font-size: 1.2rem;
        }
        .brand-icon {
            background: rgba(255, 255, 255, 0.15);
            padding: 4px 10px;
            border-radius: 40px;
            font-size: 0.9rem;
            letter-spacing: 0.5px;
        }
        .brand-name span {
            color: #ffd966;
        }
        .brand-tag {
            font-size: 0.7rem;
            background: rgba(255, 255, 255, 0.12);
            padding: 2px 10px;
            border-radius: 30px;
            font-weight: 400;
        }
        .sdh-nav {
            display: flex;
            align-items: center;
            flex-wrap: wrap;
            gap: 6px 16px;
        }
        .sdh-nav a {
            color: #fff;
            text-decoration: none;
            font-size: 0.9rem;
            opacity: 0.85;
            transition: opacity var(--transition);
            padding: 4px 2px;
        }
        .sdh-nav a:hover {
            opacity: 1;
        }
        .btn-sdh {
            background: #ffd966;
            color: var(--primary) !important;
            padding: 4px 14px !important;
            border-radius: 40px;
            font-weight: 600;
            opacity: 1 !important;
        }
        .btn-sdh:hover {
            background: #ffed4a;
        }

        /* ─── DROPDOWN ─── */
        .dropdown {
            position: relative;
            display: inline-block;
        }
        .dropbtn {
            background: transparent;
            border: none;
            color: #fff;
            font-size: 0.9rem;
            cursor: pointer;
            padding: 4px 2px;
            opacity: 0.85;
            font-family: inherit;
            display: flex;
            align-items: center;
            gap: 4px;
        }
        .dropbtn:hover {
            opacity: 1;
        }
        .dropdown-content {
            display: none;
            position: absolute;
            background: #fff;
            min-width: 200px;
            box-shadow: 0 12px 30px rgba(0, 0, 0, 0.12);
            border-radius: 12px;
            padding: 8px 0;
            top: 30px;
            left: 0;
            z-index: 10;
        }
        .dropdown-content a {
            color: var(--text) !important;
            padding: 8px 20px;
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 0.9rem;
            opacity: 1 !important;
            transition: background 0.15s;
        }
        .dropdown-content a:hover {
            background: #f1f5f9;
        }
        .dropdown:hover .dropdown-content {
            display: block;
        }

        /* ─── APP LAYOUT ─── */
        .app-wrapper {
            padding: 32px 0 20px;
        }
        .app {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* ─── CARDS ─── */
        .card {
            background: var(--card);
            border-radius: var(--radius);
            box-shadow: var(--shadow);
            padding: 28px 32px;
            margin-bottom: 32px;
            transition: box-shadow 0.2s;
        }
        .card h1 {
            font-size: 1.8rem;
            font-weight: 700;
            color: var(--primary);
            margin-bottom: 4px;
        }
        .card h2 {
            font-size: 1.3rem;
            font-weight: 600;
            color: var(--primary);
            margin-bottom: 4px;
        }
        .sub {
            color: var(--subtext);
            font-size: 0.95rem;
            margin-bottom: 20px;
        }

        /* ─── FORM ELEMENTS ─── */
        label {
            font-weight: 600;
            font-size: 0.95rem;
            display: block;
            margin-bottom: 4px;
        }
        input[type="file"] {
            display: block;
            width: 100%;
            padding: 12px 14px;
            border: 2px dashed var(--border);
            border-radius: 12px;
            background: #fafcff;
            font-size: 0.95rem;
            cursor: pointer;
            transition: border 0.2s;
            margin-bottom: 16px;
        }
        input[type="file"]:hover {
            border-color: var(--accent);
        }
        .file-info {
            font-size: 0.85rem;
            color: var(--subtext);
            margin-top: -8px;
            margin-bottom: 12px;
        }
        .row {
            display: flex;
            flex-wrap: wrap;
            gap: 20px 40px;
            margin: 8px 0 12px;
        }
        .group {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 8px 14px;
        }
        .group-label {
            font-weight: 600;
            font-size: 0.9rem;
            color: var(--subtext);
        }
        .opt {
            display: flex;
            align-items: center;
            gap: 5px;
            font-weight: 400;
            font-size: 0.9rem;
            cursor: pointer;
        }
        .opt input[type="radio"] {
            accent-color: var(--accent);
            width: 16px;
            height: 16px;
        }
        .mt-16 {
            margin-top: 16px;
        }
        .mt-8 {
            margin-top: 8px;
        }

        progress {
            width: 100%;
            height: 10px;
            border-radius: 20px;
            background: #e9edf2;
            border: none;
            margin: 6px 0 10px;
        }
        progress::-webkit-progress-bar {
            background: #e9edf2;
            border-radius: 20px;
        }
        progress::-webkit-progress-value {
            background: var(--accent);
            border-radius: 20px;
        }
        #message {
            font-weight: 500;
            min-height: 1.6em;
            margin: 2px 0 10px;
        }

        .flex-wrap {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            align-items: center;
        }
        .btn {
            background: var(--accent);
            color: #fff;
            border: none;
            padding: 10px 28px;
            border-radius: 40px;
            font-weight: 600;
            font-size: 0.95rem;
            cursor: pointer;
            transition: background 0.2s, transform 0.1s, opacity 0.2s;
            display: inline-flex;
            align-items: center;
            gap: 6px;
        }
        .btn:hover:not(:disabled) {
            background: #0b5ed7;
        }
        .btn:disabled {
            opacity: 0.5;
            cursor: not-allowed;
            transform: none;
        }
        .btn-secondary {
            background: #e9edf2;
            color: var(--text);
        }
        .btn-secondary:hover:not(:disabled) {
            background: #d5dce6;
        }
        .btn-link {
            background: transparent;
            color: var(--accent);
            padding: 8px 12px;
            text-decoration: underline;
            font-weight: 500;
        }

        .filter-row {
            display: none;
            flex-wrap: wrap;
            align-items: center;
            gap: 10px 20px;
            margin-top: 16px;
            padding-top: 12px;
            border-top: 1px solid var(--border);
        }
        .filter-row select {
            padding: 6px 14px;
            border-radius: 30px;
            border: 1px solid var(--border);
            background: #fff;
            font-size: 0.9rem;
            min-width: 140px;
        }

        /* ─── PREVIEW ─── */
        .preview {
            display: none;
        }
        #pagesContainer {
            display: flex;
            flex-wrap: wrap;
            gap: 14px;
            justify-content: center;
            margin-top: 12px;
            max-height: 600px;
            overflow-y: auto;
            padding: 4px 2px 8px;
        }
        .pageWrapper {
            display: inline-block;
            border: 2px solid var(--border);
            border-radius: 10px;
            overflow: hidden;
            background: #fff;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
            transition: border 0.2s;
            width: 140px;
        }
        .pageWrapper canvas {
            display: block;
            width: 100%;
            height: auto;
        }
        .pageWrapper.hidden {
            display: none;
        }

        /* ─── TOOLS SECTION ─── */
        .tools-grid-section {
            margin: 28px 0 16px;
            padding: 16px 0;
        }
        .tools-grid-section h2 {
            font-size: 1.4rem;
            font-weight: 700;
            color: var(--primary);
        }
        .tool-buttons {
            display: flex;
            flex-wrap: wrap;
            gap: 14px;
            margin-top: 8px;
        }
        .tool-btn {
            background: var(--card);
            border: 1px solid var(--border);
            padding: 10px 22px;
            border-radius: 50px;
            text-decoration: none;
            color: var(--text);
            font-weight: 500;
            display: inline-flex;
            align-items: center;
            gap: 8px;
            transition: background 0.15s, border-color 0.15s;
            box-shadow: var(--shadow);
        }
        .tool-btn:hover {
            background: #f1f5f9;
            border-color: var(--accent);
        }

        /* ─── INSTRUCTIONS ─── */
        .instructions {
            background: #f8faff;
            border-radius: var(--radius);
            padding: 24px 28px;
            margin: 20px 0 10px;
            border: 1px solid var(--border);
        }
        .instructions h2 {
            font-size: 1.3rem;
            font-weight: 700;
            color: var(--primary);
            margin-bottom: 12px;
        }
        .steps {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
            gap: 18px;
        }
        .step .num {
            font-weight: 700;
            font-size: 0.8rem;
            color: var(--accent);
            letter-spacing: 0.5px;
            margin-bottom: 2px;
        }
        .step p {
            font-size: 0.95rem;
            color: var(--subtext);
        }

        /* ─── FOOTER ─── */
        .sdh-footer {
            background: var(--primary);
            color: rgba(255, 255, 255, 0.8);
            padding: 32px 0 20px;
            margin-top: 30px;
        }
        .sdh-footer .container {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr;
            gap: 30px;
        }
        .sdh-footer .brand-name {
            font-size: 1.2rem;
            font-weight: 700;
            color: #fff;
        }
        .sdh-footer .brand-name span {
            color: #ffd966;
        }
        .brand-desc {
            font-size: 0.9rem;
            max-width: 320px;
            margin-top: 4px;
            opacity: 0.8;
        }
        .sdh-footer h4 {
            color: #fff;
            font-weight: 600;
            font-size: 1rem;
            margin-bottom: 6px;
        }
        .sdh-footer ul {
            list-style: none;
            padding: 0;
        }
        .sdh-footer ul li {
            margin-bottom: 4px;
        }
        .sdh-footer ul li a {
            color: rgba(255, 255, 255, 0.7);
            text-decoration: none;
            font-size: 0.9rem;
            transition: color 0.2s;
        }
        .sdh-footer ul li a:hover {
            color: #fff;
        }
        .footer-bottom {
            grid-column: 1 / -1;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            padding-top: 16px;
            margin-top: 8px;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            font-size: 0.85rem;
            opacity: 0.7;
        }
        .footer-bottom a {
            color: rgba(255, 255, 255, 0.7);
            text-decoration: none;
        }
        .footer-bottom a:hover {
            color: #fff;
        }

        /* ─── RESPONSIVE ─── */
        @media (max-width: 720px) {
            .sdh-header .container {
                flex-direction: column;
                align-items: stretch;
                gap: 6px;
            }
            .sdh-nav {
                justify-content: center;
                gap: 6px 12px;
            }
            .card {
                padding: 20px 16px;
            }
            .row {
                gap: 12px;
            }
            .sdh-footer .container {
                grid-template-columns: 1fr;
                gap: 20px;
            }
            #pagesContainer .pageWrapper {
                width: 110px;
            }
        }
        @media (max-width: 480px) {
            .brand-tag {
                display: none;
            }
            .btn {
                padding: 8px 18px;
                font-size: 0.85rem;
            }
        }

        .inline-label {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            font-weight: 500;
        }
        .inline-label input[type="checkbox"] {
            width: 18px;
            height: 18px;
            accent-color: var(--accent);
        }
        .mt-4 {
            margin-top: 6px;
        }
    </style>