/* ─────────── Reset & Variables ─────────── */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        :root {
            --sdh-orange: #f4333b;
            --sdh-red: #d32f2f;
            --sdh-dark: #1a1a2e;
            --sdh-light: #f8f6ff;
            --bg: #f4f7fc;
            --text: #1e293b;
            --subtext: #64748b;
            --border: #e9edf4;
            --shadow: rgba(0, 0, 0, 0.08);
            --radius: 12px;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
            background: var(--bg);
            color: var(--text);
            line-height: 1.6;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            align-items: center;
            padding: 0;
        }

        /* ─────────── SDH HEADER ─────────── */
        .sdh-header {
            width: 100%;
            background: #fff;
            border-bottom: 2px solid var(--sdh-orange);
            padding: 12px 0;
            box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
            position: sticky;
            top: 0;
            z-index: 200;
        }

        .sdh-header .container {
            max-width: 1000px;
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 10px;
        }

        .sdh-brand {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            color: var(--sdh-dark);
        }

        .sdh-brand .brand-icon {
            width: 38px;
            height: 38px;
            background: linear-gradient(135deg, var(--sdh-orange), var(--sdh-red));
            border-radius: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-weight: 800;
            font-size: 0.95rem;
            flex-shrink: 0;
        }

        .sdh-brand .brand-name {
            font-weight: 700;
            font-size: 1.1rem;
            letter-spacing: -0.3px;
        }

        .sdh-brand .brand-name span {
            color: var(--sdh-orange);
        }

        .sdh-brand .brand-tag {
            font-size: 0.6rem;
            color: #888;
            font-weight: 500;
            text-transform: uppercase;
            letter-spacing: 0.4px;
        }

        .sdh-nav {
            display: flex;
            align-items: center;
            gap: 4px;
            flex-wrap: wrap;
        }

        .sdh-nav a {
            padding: 6px 14px;
            border-radius: 40px;
            font-size: 0.82rem;
            font-weight: 600;
            transition: 0.25s ease;
            color: var(--text);
            text-decoration: none;
            cursor: pointer;
        }

        .sdh-nav a:hover {
            background: #f1f5f9;
        }

        .sdh-nav a.btn-sdh {
            background: var(--sdh-orange);
            color: #fff;
            box-shadow: 0 4px 12px rgba(244, 51, 59, 0.22);
        }

        .sdh-nav a.btn-sdh:hover {
            background: var(--sdh-red);
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(244, 51, 59, 0.32);
        }

        /* ─── Dropdown ─── */
        .dropdown {
            position: relative;
            display: inline-block;
        }

        .dropdown .dropbtn {
            padding: 6px 14px;
            border-radius: 40px;
            font-size: 0.82rem;
            font-weight: 600;
            transition: 0.25s ease;
            color: var(--text);
            text-decoration: none;
            background: none;
            border: none;
            cursor: pointer;
            font-family: inherit;
            display: inline-flex;
            align-items: center;
            gap: 4px;
        }

        .dropdown .dropbtn:hover {
            background: #f1f5f9;
        }

        .dropdown .dropbtn .arrow {
            font-size: 0.6rem;
            transition: transform 0.25s;
        }

        .dropdown:hover .dropbtn .arrow {
            transform: rotate(180deg);
        }

        .dropdown-content {
            display: none;
            position: absolute;
            top: 100%;
            left: 0;
            min-width: 180px;
            background: #fff;
            border-radius: 12px;
            box-shadow: 0 12px 40px rgba(0, 0, 0, 0.12);
            border: 1px solid #e9edf4;
            padding: 6px 0;
            z-index: 300;
            margin-top: 4px;
        }

        .dropdown:hover .dropdown-content {
            display: block;
        }

        .dropdown-content a {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 8px 18px;
            font-size: 0.82rem;
            font-weight: 500;
            color: var(--text);
            text-decoration: none;
            transition: 0.15s;
            border-radius: 0;
        }

        .dropdown-content a:hover {
            background: #f5f7fb;
            color: var(--sdh-orange);
        }

        .dropdown-content a .icon {
            font-size: 1.1rem;
        }

        /* ─────────── MAIN WRAPPER ─────────── */
        .app-wrapper {
            width: 100%;
            max-width: 1000px;
            padding: 20px;
            flex: 1;
        }

        .app {
            max-width: 820px;
            width: 100%;
            margin: 0 auto;
        }

        /* ─── Original app styles (kept mostly unchanged) ─── */
        .app .app-inner {
            max-width: 820px;
            width: 100%;
            background: #ffffff;
            border-radius: 2rem;
            box-shadow: 0 20px 60px rgba(0, 20, 50, 0.12);
            padding: 2.5rem 2.8rem 2.8rem;
            transition: 0.3s;
            margin-bottom: 24px;
        }

        @media (max-width: 600px) {
            .app .app-inner {
                padding: 1.5rem 1.2rem;
                border-radius: 1.2rem;
            }
        }

        .app .header {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            margin-bottom: 0.4rem;
        }

        .app .header .icon {
            font-size: 2.2rem;
            line-height: 1;
        }

        .app .header h1 {
            font-weight: 700;
            font-size: 1.9rem;
            letter-spacing: -0.5px;
            background: linear-gradient(135deg, #0f2b5b, #2563eb);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .app .subhead {
            color: #64748b;
            font-size: 0.98rem;
            margin-bottom: 2rem;
            border-left: 3px solid #2563eb;
            padding-left: 1rem;
        }

        .app .drop-zone {
            border: 2.5px dashed #cbd5e1;
            border-radius: 1.4rem;
            padding: 2.8rem 1.5rem;
            text-align: center;
            cursor: pointer;
            transition: 0.25s ease;
            background: #fafcff;
            position: relative;
        }

        .app .drop-zone:hover {
            border-color: #94a3b8;
            background: #f8faff;
        }

        .app .drop-zone.dragover {
            border-color: #2563eb;
            background: #eef4ff;
            box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.12);
        }

        .app .drop-zone .icon-big {
            font-size: 3.2rem;
            display: block;
            margin-bottom: 0.5rem;
        }

        .app .drop-zone p {
            font-size: 1.05rem;
            font-weight: 500;
            color: #1e293b;
        }

        .app .drop-zone .hint {
            font-size: 0.9rem;
            color: #94a3b8;
            margin-top: 0.3rem;
        }

        .app .drop-zone input[type="file"] {
            position: absolute;
            inset: 0;
            opacity: 0;
            cursor: pointer;
        }

        .app .file-section {
            margin-top: 2rem;
        }

        .app .file-section .section-head {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 0.75rem;
        }

        .app .file-section .section-head h2 {
            font-size: 1.1rem;
            font-weight: 600;
            color: #0f2b5b;
        }

        .app .file-section .section-head .count-badge {
            background: #e2e8f0;
            border-radius: 40px;
            padding: 0.15rem 0.8rem;
            font-size: 0.8rem;
            font-weight: 600;
            color: #334155;
        }

        .app .file-list {
            display: flex;
            flex-direction: column;
            gap: 0.6rem;
            max-height: 320px;
            overflow-y: auto;
            padding-right: 4px;
        }

        .app .file-list::-webkit-scrollbar {
            width: 5px;
        }
        .app .file-list::-webkit-scrollbar-track {
            background: #f1f5f9;
            border-radius: 8px;
        }
        .app .file-list::-webkit-scrollbar-thumb {
            background: #cbd5e1;
            border-radius: 8px;
        }

        .app .file-item {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            background: #f8fafc;
            padding: 0.65rem 1rem 0.65rem 1.2rem;
            border-radius: 0.9rem;
            border: 1px solid #e9edf2;
            transition: 0.2s;
            animation: slideIn 0.25s ease;
        }

        .app .file-item:hover {
            background: #f1f5f9;
            border-color: #d1d9e6;
        }

        .app .file-item .file-icon {
            font-size: 1.5rem;
            flex-shrink: 0;
        }

        .app .file-item .file-info {
            flex: 1;
            min-width: 0;
        }

        .app .file-item .file-name {
            font-weight: 500;
            font-size: 0.95rem;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .app .file-item .file-size {
            font-size: 0.75rem;
            color: #94a3b8;
        }

        .app .file-item .file-actions {
            display: flex;
            gap: 0.3rem;
            flex-shrink: 0;
        }

        .app .file-item .file-actions button {
            background: transparent;
            border: none;
            width: 30px;
            height: 30px;
            border-radius: 8px;
            font-size: 1rem;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: 0.15s;
            color: #64748b;
        }

        .app .file-item .file-actions button:hover {
            background: #e2e8f0;
            color: #0f172a;
        }

        .app .file-item .file-actions .remove-btn:hover {
            background: #fee2e2;
            color: #b91c1c;
        }

        .app .file-item .file-actions button:disabled {
            opacity: 0.3;
            cursor: not-allowed;
        }

        .app .actions {
            display: flex;
            flex-wrap: wrap;
            gap: 0.8rem;
            margin-top: 1.6rem;
            align-items: center;
        }

        .app .btn {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            padding: 0.7rem 1.6rem;
            border-radius: 60px;
            font-weight: 600;
            font-size: 0.95rem;
            border: none;
            cursor: pointer;
            transition: 0.2s;
            background: #e2e8f0;
            color: #1e293b;
        }

        .app .btn-primary {
            background: #2563eb;
            color: #fff;
            box-shadow: 0 4px 14px rgba(37, 99, 235, 0.28);
        }

        .app .btn-primary:hover:not(:disabled) {
            background: #1d4ed8;
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(37, 99, 235, 0.34);
        }

        .app .btn-primary:disabled {
            opacity: 0.5;
            cursor: not-allowed;
            transform: none;
        }

        .app .btn-success {
            background: #16a34a;
            color: #fff;
            box-shadow: 0 4px 14px rgba(22, 163, 74, 0.28);
        }

        .app .btn-success:hover {
            background: #15803d;
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(22, 163, 74, 0.34);
        }

        .app .btn-outline {
            background: transparent;
            border: 1.5px solid #cbd5e1;
        }

        .app .btn-outline:hover {
            background: #f1f5f9;
            border-color: #94a3b8;
        }

        .app .btn-danger-outline {
            background: transparent;
            border: 1.5px solid #fca5a5;
            color: #b91c1c;
        }

        .app .btn-danger-outline:hover {
            background: #fef2f2;
            border-color: #ef4444;
        }

        .app .status-area {
            margin-top: 1.8rem;
            padding-top: 1.2rem;
            border-top: 1.5px solid #edf2f7;
        }

        .app .status-message {
            display: flex;
            align-items: center;
            gap: 0.6rem;
            font-size: 0.95rem;
            color: #475569;
            min-height: 2.6rem;
        }

        .app .status-message .spinner {
            display: inline-block;
            width: 22px;
            height: 22px;
            border: 3px solid #e2e8f0;
            border-top: 3px solid #2563eb;
            border-radius: 50%;
            animation: spin 0.7s linear infinite;
        }

        .app .status-message .success-icon {
            color: #16a34a;
            font-size: 1.4rem;
        }

        .app .status-message .error-icon {
            color: #dc2626;
            font-size: 1.4rem;
        }

        .app .result-actions {
            margin-top: 0.8rem;
            display: flex;
            flex-wrap: wrap;
            gap: 0.8rem;
        }

        .app .empty-state {
            text-align: center;
            padding: 1.2rem 0 0.4rem;
            color: #94a3b8;
            font-size: 0.95rem;
        }

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

        @keyframes spin {
            to {
                transform: rotate(360deg);
            }
        }

        .app .hidden {
            display: none !important;
        }

        .app .mt-1 {
            margin-top: 0.6rem;
        }

        .app .text-sm {
            font-size: 0.85rem;
        }

        .app .text-muted {
            color: #94a3b8;
        }

        @media (max-width: 480px) {
            .app .app-inner {
                padding: 1.5rem 1.2rem;
            }
            .app .header h1 {
                font-size: 1.5rem;
            }
            .app .drop-zone {
                padding: 2rem 1rem;
            }
            .app .drop-zone .icon-big {
                font-size: 2.4rem;
            }
            .app .btn {
                padding: 0.6rem 1.2rem;
                font-size: 0.85rem;
            }
            .app .file-item {
                padding: 0.5rem 0.7rem;
                flex-wrap: wrap;
            }
            .app .file-item .file-actions {
                margin-left: auto;
            }
            .app .actions {
                flex-direction: column;
                align-items: stretch;
            }
            .app .actions .btn {
                justify-content: center;
            }
        }

        /* ─────────── TOOLS SECTION ─────────── */
        .tools-grid-section {
            background: #fff;
            border-radius: 2rem;
            box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
            padding: 28px 32px;
            margin-bottom: 24px;
        }

        .tools-grid-section h2 {
            font-size: 1.3rem;
            margin-bottom: 6px;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .tools-grid-section .sub {
            color: var(--subtext);
            font-size: 0.95rem;
            margin-bottom: 18px;
        }

        .tools-grid-section .tool-buttons {
            display: flex;
            flex-wrap: wrap;
            gap: 16px;
        }

        .tools-grid-section .tool-btn {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            padding: 14px 28px;
            border-radius: var(--radius);
            font-weight: 600;
            font-size: 0.95rem;
            text-decoration: none;
            transition: 0.25s ease;
            border: 2px solid transparent;
            background: #f8fafc;
            color: var(--text);
            border-color: #e9edf4;
        }

        .tools-grid-section .tool-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
            border-color: var(--sdh-orange);
        }

        .tools-grid-section .tool-btn.primary-btn {
            background: var(--sdh-orange);
            color: #fff;
            border-color: var(--sdh-orange);
            box-shadow: 0 4px 14px rgba(244, 51, 59, 0.22);
        }

        .tools-grid-section .tool-btn.primary-btn:hover {
            background: var(--sdh-red);
            border-color: var(--sdh-red);
            box-shadow: 0 6px 24px rgba(244, 51, 59, 0.32);
        }

        .tools-grid-section .tool-btn .icon {
            font-size: 1.3rem;
        }

        /* ─────────── INSTRUCTIONS ─────────── */
        .instructions {
            background: #fff;
            border-radius: 2rem;
            box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
            padding: 28px 32px;
            margin-bottom: 24px;
            scroll-margin-top: 80px;
        }

        .instructions h2 {
            font-size: 1.3rem;
            margin-bottom: 8px;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .instructions .steps {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 16px;
            margin-top: 12px;
        }

        .instructions .step {
            background: #f8fafc;
            padding: 16px 18px;
            border-radius: var(--radius);
            border-left: 3px solid var(--sdh-orange);
        }

        .instructions .step .num {
            font-weight: 700;
            color: var(--sdh-orange);
            font-size: 0.75rem;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }

        .instructions .step p {
            font-size: 0.92rem;
            color: var(--subtext);
            margin-top: 2px;
        }

        /* ─────────── FOOTER ─────────── */
        .sdh-footer {
            width: 100%;
            background: var(--sdh-dark);
            color: rgba(255, 255, 255, 0.8);
            padding: 32px 20px 20px;
            margin-top: 20px;
            border-top: 3px solid var(--sdh-orange);
            scroll-margin-top: 80px;
        }

        .sdh-footer .container {
            max-width: 1000px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 2fr 1fr 1fr;
            gap: 28px;
        }

        .sdh-footer .brand-name {
            color: #fff;
            font-size: 1.2rem;
            font-weight: 700;
        }

        .sdh-footer .brand-name span {
            color: var(--sdh-orange);
        }

        .sdh-footer .brand-desc {
            font-size: 0.9rem;
            color: rgba(255, 255, 255, 0.6);
            margin-top: 6px;
            max-width: 300px;
        }

        .sdh-footer h4 {
            color: #fff;
            font-size: 0.95rem;
            font-weight: 600;
            margin-bottom: 10px;
        }

        .sdh-footer ul {
            list-style: none;
            padding: 0;
        }

        .sdh-footer ul li {
            margin-bottom: 6px;
        }

        .sdh-footer ul li a {
            color: rgba(255, 255, 255, 0.6);
            font-size: 0.88rem;
            text-decoration: none;
            transition: 0.2s;
            display: inline-flex;
            align-items: center;
            gap: 6px;
        }

        .sdh-footer ul li a:hover {
            color: var(--sdh-orange);
            transform: translateX(4px);
        }

        .sdh-footer .footer-bottom {
            grid-column: 1 / -1;
            border-top: 1px solid rgba(255, 255, 255, 0.06);
            padding-top: 16px;
            margin-top: 8px;
            display: flex;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 10px;
            font-size: 0.78rem;
            color: rgba(255, 255, 255, 0.35);
        }

        .sdh-footer .footer-bottom a {
            color: rgba(255, 255, 255, 0.4);
            text-decoration: none;
            transition: 0.2s;
        }

        .sdh-footer .footer-bottom a:hover {
            color: var(--sdh-orange);
        }

        /* ─────────── Responsive ─────────── */
        @media (max-width: 700px) {
            .sdh-footer .container {
                grid-template-columns: 1fr 1fr;
            }
            .sdh-footer .brand-col {
                grid-column: 1 / -1;
            }
            .sdh-footer .brand-desc {
                max-width: 100%;
            }
            .sdh-header .container {
                flex-direction: column;
                align-items: stretch;
                gap: 6px;
            }
            .sdh-brand {
                justify-content: center;
            }
            .sdh-nav {
                justify-content: center;
            }
            .tools-grid-section .tool-buttons {
                flex-direction: column;
            }
            .tools-grid-section .tool-btn {
                justify-content: center;
            }
            .instructions .steps {
                grid-template-columns: 1fr;
            }
            .dropdown-content {
                left: 50%;
                transform: translateX(-50%);
            }
            .tools-grid-section,
            .instructions {
                padding: 20px 18px;
            }
        }

        @media (max-width: 480px) {
            .sdh-footer .container {
                grid-template-columns: 1fr;
                gap: 18px;
            }
            .sdh-footer .brand-col {
                grid-column: 1;
            }
            .app-wrapper {
                padding: 12px;
            }
            .tools-grid-section,
            .instructions {
                padding: 16px 14px;
            }
            .sdh-nav a,
            .dropdown .dropbtn {
                padding: 4px 10px;
                font-size: 0.72rem;
            }
            .dropdown-content {
                min-width: 160px;
            }
            .dropdown-content a {
                padding: 6px 14px;
                font-size: 0.75rem;
            }
        }