:root {
            --primary: #2563eb;
            --primary-hover: #1d4ed8;
            --primary-light: #dbeafe;
            --primary-50: #eff6ff;
            --secondary: #0f172a;
            --bg: #f8fafc;
            --card-bg: #ffffff;
            --text: #1e293b;
            --text-secondary: #64748b;
            --text-muted: #94a3b8;
            --border: #e2e8f0;
            --border-light: #f1f5f9;
            --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
            --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
            --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05), 0 2px 4px rgba(0, 0, 0, 0.04);
            --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.06), 0 4px 10px rgba(0, 0, 0, 0.03);
            --radius-sm: 8px;
            --radius: 12px;
            --radius-lg: 16px;
            --radius-xl: 20px;
            --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
            --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            --max-width: 1280px;
            --header-height: 60px;
            --ad-subtle-border: rgba(148, 163, 184, 0.18);
            --ad-subtle-bg: rgba(248, 250, 252, 0.6);
            --icon-stroke: currentColor;
            --footer-separator: rgba(148, 163, 184, 0.14);
            --footer-trust-bg: rgba(37, 99, 235, 0.04);
            --footer-updated-dot: #3b82f6;
            --footer-new-dot: #f59e0b;
        }
        .dark {
            --bg: #0f172a;
            --card-bg: #1e293b;
            --text: #f1f5f9;
            --text-secondary: #cbd5e1;
            --text-muted: #94a3b8;
            --border: #334155;
            --border-light: #1e293b;
            --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.25);
            --shadow: 0 1px 3px rgba(0, 0, 0, 0.35), 0 1px 2px rgba(0, 0, 0, 0.25);
            --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.35), 0 2px 4px rgba(0, 0, 0, 0.25);
            --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
            --primary-light: #1e3a6e;
            --primary-50: #172554;
            --ad-subtle-border: rgba(148, 163, 184, 0.12);
            --ad-subtle-bg: rgba(30, 41, 59, 0.4);
            --footer-separator: rgba(148, 163, 184, 0.08);
            --footer-trust-bg: rgba(37, 99, 235, 0.06);
            --footer-updated-dot: #60a5fa;
            --footer-new-dot: #fbbf24;
        }
        .dark .trust-badge-icon {
            background: #1e3a6e;
        }
        .dark .featured-calc {
            background: #1a2744;
        }
        .dark input,
        .dark select {
            background: #1e293b;
            color: #f1f5f9;
            border-color: #334155;
        }
        .dark input:focus {
            border-color: #3b82f6;
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
        }
        .dark .demo-result {
            background: #052e16;
            border-color: #166534;
            color: #bbf7d0;
        }
        .dark .search-overlay {
            background: rgba(0, 0, 0, 0.8);
        }
        .dark .search-modal {
            background: #1e293b;
            border-color: #334155;
        }
        .dark .search-result-card {
            background: #1e293b;
            border-color: #334155;
        }
        .dark .search-result-card:hover {
            background: #1a2744;
            border-color: #3b82f6;
        }

        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            scroll-behavior: smooth;
            font-size: 16px;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }
        body {
            font-family: var(--font-sans);
            background-color: var(--bg);
            color: var(--text);
            line-height: 1.6;
            min-height: 100vh;
            transition: background-color var(--transition), color var(--transition);
        }
        body.search-open {
            overflow: hidden;
        }

        .svg-icon {
            display: block;
            flex-shrink: 0;
            stroke: currentColor;
            fill: none;
            stroke-width: 2;
            stroke-linecap: round;
            stroke-linejoin: round;
            width: 1em;
            height: 1em;
            vertical-align: middle;
        }
        .svg-icon-filled {
            fill: currentColor;
            stroke: none;
        }

        .site-header {
            position: sticky;
            top: 0;
            z-index: 100;
            background: var(--card-bg);
            border-bottom: 1px solid var(--border);
            height: var(--header-height);
            display: flex;
            align-items: center;
            transition: background-color var(--transition), border-color var(--transition), box-shadow var(--transition);
            box-shadow: var(--shadow-sm);
        }
        .header-inner {
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 16px;
        }
        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            flex-shrink: 0;
        }
        .header-actions {
            display: flex;
            align-items: center;
            gap: 6px;
            flex-shrink: 0;
        }
        .icon-btn {
            width: 38px;
            height: 38px;
            border-radius: 50%;
            border: 1.5px solid var(--border);
            background: var(--card-bg);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all var(--transition);
            color: var(--text);
            flex-shrink: 0;
            line-height: 1;
            padding: 0;
        }
        .icon-btn:hover {
            border-color: var(--primary);
            background: var(--primary-50);
        }
        .icon-btn:focus-visible {
            outline: 2px solid var(--primary);
            outline-offset: 2px;
        }
        .dark .icon-btn:hover {
            background: #1e3a6e;
            border-color: #3b82f6;
        }
        .icon-btn .svg-icon {
            width: 1.15rem;
            height: 1.15rem;
        }

        .search-overlay {
            position: fixed;
            inset: 0;
            z-index: 200;
            background: rgba(0, 0, 0, 0.55);
            display: flex;
            align-items: flex-start;
            justify-content: center;
            padding: 70px 20px 40px;
            opacity: 0;
            pointer-events: none;
            transition: opacity 0.2s ease;
        }
        .search-overlay.active {
            opacity: 1;
            pointer-events: auto;
        }
        .search-modal {
            width: 100%;
            max-width: 600px;
            background: var(--card-bg);
            border-radius: var(--radius-xl);
            border: 1px solid var(--border);
            box-shadow: var(--shadow-lg);
            overflow: hidden;
            display: flex;
            flex-direction: column;
            max-height: 65vh;
        }
        .search-modal-header {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 14px 18px;
            border-bottom: 1px solid var(--border);
            flex-shrink: 0;
        }
        .search-modal-header .svg-icon {
            width: 1.15rem;
            height: 1.15rem;
            color: var(--text-muted);
            flex-shrink: 0;
        }
        .search-modal-input {
            flex: 1;
            border: none;
            padding: 8px 0;
            font-size: 1.05rem;
            font-family: var(--font-sans);
            background: transparent;
            color: var(--text);
            outline: none;
        }
        .search-modal-input::placeholder {
            color: var(--text-muted);
        }
        .search-modal-close {
            width: 34px;
            height: 34px;
            border-radius: 50%;
            border: 1.5px solid var(--border);
            background: var(--card-bg);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text);
            transition: all var(--transition);
            flex-shrink: 0;
            line-height: 1;
            padding: 0;
        }
        .search-modal-close:hover {
            border-color: #ef4444;
            color: #ef4444;
            background: #fef2f2;
        }
        .dark .search-modal-close:hover {
            background: #3b1a1a;
        }
        .search-modal-close .svg-icon {
            width: 0.85rem;
            height: 0.85rem;
        }
        .search-results {
            overflow-y: auto;
            padding: 6px;
            flex: 1;
            display: flex;
            flex-direction: column;
            gap: 3px;
        }
        .search-result-card {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 10px 12px;
            border-radius: var(--radius);
            cursor: pointer;
            text-decoration: none;
            color: var(--text);
            border: 1px solid transparent;
            background: var(--card-bg);
            transition: all var(--transition);
        }
        .search-result-card:hover {
            background: var(--primary-50);
            border-color: var(--primary-light);
        }
        .dark .search-result-card:hover {
            background: #1a2744;
            border-color: #3b82f6;
        }
        .search-result-icon {
            width: 36px;
            height: 36px;
            border-radius: var(--radius-sm);
            background: var(--primary-50);
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
        }
        .search-result-icon .svg-icon {
            width: 1.05rem;
            height: 1.05rem;
            color: var(--primary);
        }
        .search-result-info h4 {
            font-size: 0.88rem;
            font-weight: 600;
            letter-spacing: -0.01em;
        }
        .search-result-info span {
            font-size: 0.73rem;
            color: var(--text-muted);
        }
        .search-no-results {
            text-align: center;
            padding: 28px 16px;
            color: var(--text-muted);
            font-size: 0.88rem;
        }
        .search-hint {
            text-align: center;
            padding: 24px 16px;
            color: var(--text-muted);
            font-size: 0.83rem;
        }

        .main-content {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 20px;
        }
        .section {
            padding: 36px 0;
        }
        .section-header {
            text-align: center;
            margin-bottom: 28px;
        }
        .section-header h2 {
            font-size: 1.7rem;
            font-weight: 700;
            letter-spacing: -0.02em;
            color: var(--secondary);
            margin-bottom: 6px;
        }
        .dark .section-header h2 {
            color: #f1f5f9;
        }
        .section-header p {
            color: var(--text-secondary);
            font-size: 1rem;
            max-width: 560px;
            margin: 0 auto;
        }

        .hero {
            text-align: center;
            padding: 40px 0 32px;
        }
        .hero h1 {
            font-size: clamp(1.7rem, 3.2vw, 2.4rem);
            font-weight: 800;
            letter-spacing: -0.03em;
            color: var(--secondary);
            line-height: 1.2;
            margin-bottom: 10px;
            max-width: 650px;
            margin-left: auto;
            margin-right: auto;
        }
        .dark .hero h1 {
            color: #f8fafc;
        }
        .hero .hero-sub {
            font-size: 1.05rem;
            color: var(--text-secondary);
            max-width: 560px;
            margin: 0 auto 24px;
            line-height: 1.5;
        }
        .hero-btns {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
            justify-content: center;
            margin-bottom: 24px;
        }
        .btn {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 11px 22px;
            border-radius: 999px;
            font-weight: 600;
            font-size: 0.93rem;
            cursor: pointer;
            text-decoration: none;
            transition: all var(--transition);
            border: none;
            font-family: var(--font-sans);
            white-space: nowrap;
            letter-spacing: -0.01em;
        }
        .btn-primary {
            background: var(--primary);
            color: #fff;
            box-shadow: 0 3px 12px rgba(37, 99, 235, 0.3);
        }
        .btn-primary:hover {
            background: var(--primary-hover);
            box-shadow: 0 5px 18px rgba(37, 99, 235, 0.38);
            transform: translateY(-1px);
        }
        .btn-primary:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none;
            box-shadow: none;
        }
        .btn-outline {
            background: var(--card-bg);
            color: var(--primary);
            border: 2px solid var(--border);
        }
        .btn-outline:hover {
            border-color: var(--primary);
            background: var(--primary-50);
        }
        .dark .btn-outline {
            border-color: #334155;
        }
        .dark .btn-outline:hover {
            background: #1e3a6e;
            border-color: #3b82f6;
        }
        .btn-sm {
            padding: 9px 16px;
            font-size: 0.88rem;
            border-radius: 999px;
            font-weight: 600;
            cursor: pointer;
            border: none;
            font-family: var(--font-sans);
            transition: all var(--transition);
            letter-spacing: -0.01em;
            background: var(--primary);
            color: #fff;
        }
        .btn-sm:hover {
            background: var(--primary-hover);
        }
        .btn-sm:disabled {
            opacity: 0.55;
            cursor: not-allowed;
        }
        .trust-badges {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            justify-content: center;
        }
        .trust-badge {
            display: flex;
            align-items: center;
            gap: 7px;
            font-size: 0.83rem;
            color: var(--text-secondary);
            font-weight: 500;
            background: var(--card-bg);
            padding: 7px 14px;
            border-radius: 999px;
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition);
        }
        .trust-badge-icon {
            width: 26px;
            height: 26px;
            border-radius: 50%;
            background: var(--primary-light);
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
        }
        .trust-badge-icon .svg-icon {
            width: 0.8rem;
            height: 0.8rem;
            color: var(--primary);
        }

        .ad-container {
            width: 100%;
            background: var(--ad-subtle-bg);
            border: 1px dashed var(--ad-subtle-border);
            border-radius: var(--radius);
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 60px;
            padding: 14px 16px;
            margin: 12px 0;
            transition: all var(--transition);
            color: var(--text-muted);
            font-size: 0.68rem;
            letter-spacing: 0.05em;
            text-transform: uppercase;
            text-align: center;
            opacity: 0.7;
        }
        .ad-container.ad-leaderboard {
            min-height: 70px;
            max-height: 100px;
        }
        .ad-container.ad-rectangle {
            min-height: 200px;
            max-width: 300px;
            margin-left: auto;
            margin-right: auto;
        }
        .ad-container.ad-inline {
            min-height: 70px;
            max-height: 110px;
            margin: 18px 0;
        }
        .ad-inline-mini {
            width: 100%;
            background: var(--ad-subtle-bg);
            border: 1px dashed var(--ad-subtle-border);
            border-radius: var(--radius-sm);
            min-height: 48px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 0.65rem;
            color: var(--text-muted);
            letter-spacing: 0.05em;
            text-transform: uppercase;
            padding: 8px;
            opacity: 0.65;
            transition: opacity var(--transition);
        }
        @media (min-width: 769px) {
            .ad-container.ad-leaderboard {
                min-height: 80px;
                max-height: 110px;
            }
            .ad-container.ad-rectangle {
                min-height: 220px;
            }
        }
        @media (max-width: 480px) {
            .ad-container.ad-rectangle {
                min-height: 160px;
                max-width: 100%;
            }
            .ad-container.ad-leaderboard {
                min-height: 55px;
                max-height: 80px;
            }
            .ad-container {
                padding: 10px 12px;
                font-size: 0.62rem;
            }
        }

        .cards-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
            gap: 14px;
        }
        .calc-card {
            background: var(--card-bg);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-lg);
            padding: 18px;
            cursor: pointer;
            transition: all var(--transition);
            text-decoration: none;
            color: inherit;
            display: flex;
            align-items: flex-start;
            gap: 12px;
            box-shadow: var(--shadow-sm);
            position: relative;
        }
        .calc-card:hover {
            box-shadow: var(--shadow-lg);
            border-color: var(--primary);
            transform: translateY(-2px);
        }
        .calc-card-icon {
            width: 40px;
            height: 40px;
            border-radius: var(--radius);
            background: var(--primary-50);
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            transition: all var(--transition);
        }
        .calc-card-icon .svg-icon {
            width: 1.2rem;
            height: 1.2rem;
            color: var(--primary);
        }
        .calc-card:hover .calc-card-icon {
            background: var(--primary-light);
            transform: scale(1.04);
        }
        .calc-card-info h3 {
            font-size: 0.92rem;
            font-weight: 600;
            letter-spacing: -0.01em;
            margin-bottom: 2px;
            color: var(--secondary);
        }
        .dark .calc-card-info h3 {
            color: #f1f5f9;
        }
        .calc-card-info p {
            font-size: 0.78rem;
            color: var(--text-muted);
            line-height: 1.4;
            margin: 0;
        }

        .category-card {
            background: var(--card-bg);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-lg);
            padding: 20px 18px;
            text-align: center;
            transition: all var(--transition);
            box-shadow: var(--shadow-sm);
            text-decoration: none;
            color: inherit;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 8px;
        }
        .category-card:hover {
            box-shadow: var(--shadow-lg);
            border-color: var(--primary);
            transform: translateY(-2px);
        }
        .category-icon {
            width: 48px;
            height: 48px;
            border-radius: var(--radius);
            background: var(--primary-50);
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all var(--transition);
        }
        .category-icon .svg-icon {
            width: 1.5rem;
            height: 1.5rem;
            color: var(--primary);
        }
        .category-card:hover .category-icon {
            background: var(--primary-light);
            transform: scale(1.06);
        }
        .category-card h3 {
            font-weight: 600;
            font-size: 0.92rem;
            letter-spacing: -0.01em;
            color: var(--secondary);
        }
        .dark .category-card h3 {
            color: #f1f5f9;
        }
        .cat-count {
            font-size: 0.76rem;
            color: var(--text-muted);
            background: var(--bg);
            padding: 3px 10px;
            border-radius: 999px;
            font-weight: 500;
        }
        .dark .cat-count {
            background: #0f172a;
        }
        .category-link {
            color: var(--primary);
            font-weight: 600;
            font-size: 0.82rem;
            text-decoration: none;
            transition: color var(--transition);
        }
        .category-link:hover {
            text-decoration: underline;
        }

        .featured-calc {
            background: var(--primary-50);
            border-radius: var(--radius-xl);
            padding: 28px 24px;
            display: flex;
            flex-wrap: wrap;
            gap: 24px;
            align-items: flex-start;
            border: 1.5px solid var(--primary-light);
            box-shadow: var(--shadow-md);
            transition: all var(--transition);
        }
        .dark .featured-calc {
            background: #1a2744;
            border-color: #1e3a6e;
        }
        .featured-calc-info {
            flex: 1;
            min-width: 220px;
        }
        .featured-calc-info .badge {
            display: inline-block;
            background: var(--primary);
            color: #fff;
            font-size: 0.72rem;
            font-weight: 700;
            padding: 3px 10px;
            border-radius: 999px;
            margin-bottom: 8px;
            letter-spacing: 0.02em;
        }
        .featured-calc-info h3 {
            font-size: 1.35rem;
            font-weight: 700;
            letter-spacing: -0.02em;
            margin-bottom: 5px;
            color: var(--secondary);
        }
        .dark .featured-calc-info h3 {
            color: #f8fafc;
        }
        .featured-calc-info p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            margin-bottom: 14px;
            line-height: 1.5;
        }
        .featured-calc-demo {
            flex: 1;
            min-width: 260px;
            background: var(--card-bg);
            border-radius: var(--radius-lg);
            padding: 18px 20px;
            box-shadow: var(--shadow-md);
            border: 1px solid var(--border);
            display: flex;
            flex-direction: column;
            gap: 10px;
        }
        .featured-calc-demo label {
            font-weight: 600;
            font-size: 0.82rem;
            color: var(--text-secondary);
            letter-spacing: -0.01em;
        }
        .featured-calc-demo input {
            padding: 9px 12px;
            border: 1.5px solid var(--border);
            border-radius: var(--radius-sm);
            font-size: 0.95rem;
            font-family: var(--font-sans);
            transition: all var(--transition);
            width: 100%;
            background: var(--bg);
            color: var(--text);
        }
        .featured-calc-demo input:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.08);
        }
        .demo-input-row {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }
        .demo-input-row>div {
            flex: 1;
            min-width: 90px;
        }
        .demo-result {
            background: #f0fdf4;
            border: 1px solid #bbf7d0;
            border-radius: var(--radius-sm);
            padding: 12px 14px;
            font-weight: 700;
            font-size: 1rem;
            color: #166534;
            text-align: center;
            min-height: 42px;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s ease;
            flex-direction: column;
            gap: 3px;
        }
        .demo-result .result-label {
            font-size: 0.73rem;
            font-weight: 500;
            color: #166534;
            opacity: 0.7;
        }
        .skeleton-loader {
            background: var(--bg);
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            padding: 14px 16px;
            min-height: 42px;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
            transition: all 0.25s ease;
        }
        .skeleton-spinner {
            width: 20px;
            height: 20px;
            border: 2.5px solid var(--border);
            border-top-color: var(--primary);
            border-radius: 50%;
            animation: spin 0.7s linear infinite;
        }
        @keyframes spin { to { transform: rotate(360deg); } }
        .skeleton-pulse {
            width: 55%;
            height: 10px;
            background: var(--border);
            border-radius: 5px;
            animation: pulse 1.5s ease-in-out infinite;
        }
        @keyframes pulse {
            0%,
            100% { opacity: 0.35; }
            50% { opacity: 0.75; }
        }
        .result-fade-in {
            animation: fadeSlideIn 0.35s ease-out;
        }
        @keyframes fadeSlideIn {
            from { opacity: 0; transform: translateY(6px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .why-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
            gap: 14px;
        }
        .why-card {
            background: var(--card-bg);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-lg);
            padding: 20px 16px;
            text-align: center;
            box-shadow: var(--shadow-sm);
            transition: all var(--transition);
        }
        .why-card:hover {
            box-shadow: var(--shadow-md);
            transform: translateY(-2px);
        }
        .why-icon {
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 8px;
        }
        .why-icon .svg-icon {
            width: 1.8rem;
            height: 1.8rem;
            color: var(--primary);
        }
        .why-card h4 {
            font-weight: 600;
            font-size: 0.9rem;
            margin-bottom: 3px;
            letter-spacing: -0.01em;
            color: var(--secondary);
        }
        .dark .why-card h4 {
            color: #f1f5f9;
        }
        .why-card p {
            font-size: 0.78rem;
            color: var(--text-muted);
            margin: 0;
        }

        .related-mini-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
            gap: 10px;
        }
        .related-mini-card {
            background: var(--card-bg);
            border: 1px solid var(--border-light);
            border-radius: var(--radius);
            padding: 14px 16px;
            text-decoration: none;
            color: inherit;
            display: flex;
            align-items: center;
            gap: 10px;
            transition: all var(--transition);
            box-shadow: var(--shadow-sm);
        }
        .related-mini-card:hover {
            border-color: var(--primary);
            box-shadow: var(--shadow-md);
            transform: translateY(-1px);
        }
        .related-mini-icon {
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
        }
        .related-mini-icon .svg-icon {
            width: 1.2rem;
            height: 1.2rem;
            color: var(--primary);
        }
        .related-mini-card span {
            font-weight: 500;
            font-size: 0.85rem;
            letter-spacing: -0.01em;
        }

        .seo-block {
            background: var(--card-bg);
            border-radius: var(--radius-xl);
            padding: 28px 24px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
        }
        .seo-block h2 {
            font-size: 1.4rem;
            font-weight: 700;
            margin-bottom: 14px;
            letter-spacing: -0.02em;
            color: var(--secondary);
        }
        .dark .seo-block h2 {
            color: #f8fafc;
        }
        .seo-block h3 {
            font-size: 1.1rem;
            font-weight: 600;
            margin: 18px 0 6px;
            letter-spacing: -0.01em;
            color: var(--secondary);
        }
        .dark .seo-block h3 {
            color: #f1f5f9;
        }
        .seo-block p,
        .seo-block li {
            color: var(--text-secondary);
            font-size: 0.92rem;
            line-height: 1.65;
        }
        .seo-block ul {
            list-style: disc;
            padding-left: 18px;
            margin: 6px 0 14px;
        }
        .seo-block ul li {
            margin-bottom: 3px;
        }
        .trust-section {
            background: var(--card-bg);
            border-radius: var(--radius-xl);
            padding: 24px 22px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            margin-bottom: 20px;
        }
        .trust-section h3 {
            font-size: 1.15rem;
            font-weight: 700;
            letter-spacing: -0.02em;
            margin-bottom: 10px;
            color: var(--secondary);
        }
        .dark .trust-section h3 {
            color: #f1f5f9;
        }
        .trust-section p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            line-height: 1.6;
            margin-bottom: 6px;
        }
        .trust-section ul {
            list-style: disc;
            padding-left: 18px;
            margin: 6px 0;
            color: var(--text-secondary);
            font-size: 0.9rem;
            line-height: 1.6;
        }
        .trust-section ul li {
            margin-bottom: 3px;
        }

        .faq-list {
            display: flex;
            flex-direction: column;
            gap: 8px;
            max-width: 720px;
            margin: 0 auto;
        }
        .faq-item {
            background: var(--card-bg);
            border: 1px solid var(--border);
            border-radius: var(--radius-lg);
            overflow: hidden;
            transition: all var(--transition);
            box-shadow: var(--shadow-sm);
        }
        .faq-question {
            width: 100%;
            background: none;
            border: none;
            padding: 16px 18px;
            font-size: 0.95rem;
            font-weight: 600;
            cursor: pointer;
            text-align: left;
            display: flex;
            justify-content: space-between;
            align-items: center;
            color: var(--secondary);
            font-family: var(--font-sans);
            letter-spacing: -0.01em;
            gap: 10px;
            transition: color var(--transition);
        }
        .dark .faq-question {
            color: #f1f5f9;
        }
        .faq-question:hover {
            color: var(--primary);
        }
        .faq-arrow {
            flex-shrink: 0;
            transition: transform var(--transition);
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-muted);
        }
        .faq-arrow .svg-icon {
            width: 0.75rem;
            height: 0.75rem;
        }
        .faq-item.open .faq-arrow {
            transform: rotate(180deg);
            color: var(--primary);
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease, padding 0.35s ease;
            padding: 0 18px;
            font-size: 0.87rem;
            color: var(--text-secondary);
            line-height: 1.6;
        }
        .faq-item.open .faq-answer {
            max-height: 220px;
            padding: 0 18px 16px;
        }

        .badge-row {
            display: flex;
            flex-wrap: wrap;
            gap: 7px;
            justify-content: center;
            margin-top: 6px;
        }
        .tag-badge {
            display: inline-flex;
            align-items: center;
            gap: 4px;
            padding: 5px 12px;
            border-radius: 999px;
            font-size: 0.78rem;
            font-weight: 500;
            background: var(--card-bg);
            border: 1px solid var(--border);
            color: var(--text-secondary);
            text-decoration: none;
            transition: all var(--transition);
            cursor: pointer;
        }
        .tag-badge:hover {
            border-color: var(--primary);
            color: var(--primary);
            background: var(--primary-50);
        }
        .tag-badge.new {
            background: #fef3c7;
            border-color: #fcd34d;
            color: #92400e;
        }
        .dark .tag-badge.new {
            background: #422006;
            border-color: #78350f;
            color: #fcd34d;
        }
        .tag-badge.popular {
            background: #dbeafe;
            border-color: #93c5fd;
            color: #1e40af;
        }
        .dark .tag-badge.popular {
            background: #1e3a6e;
            border-color: #2563eb;
            color: #93c5fd;
        }
        .tag-badge .badge-dot {
            display: inline-block;
            width: 6px;
            height: 6px;
            border-radius: 50%;
            flex-shrink: 0;
        }
        .tag-badge.new .badge-dot {
            background: #f59e0b;
        }
        .tag-badge.popular .badge-dot {
            background: #3b82f6;
        }

        .last-updated {
            text-align: center;
            font-size: 0.75rem;
            color: var(--text-muted);
            padding: 6px 0;
            letter-spacing: 0.02em;
        }


        /* site logo images (light/dark) */
        .site-logo {
            content: url('https://numbrwiz.com/logo-light.svg');
            height: 48px;
            width: auto;
            display: block;
        }
        .dark .site-logo {
            content: url('https://numbrwiz.com/logo-dark.svg');
        }
        .footer-logo-img {
            height: 42px;
            width: auto;
            display: block;
        }

        @media (max-width: 768px) {
            .section { padding: 28px 0; }
            .hero { padding: 28px 0 24px; }
            .hero h1 { font-size: 1.5rem; }
            .featured-calc { flex-direction: column; padding: 20px 16px; }
            .cards-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 10px; }
            .calc-card { padding: 14px; gap: 10px; }
            .calc-card-icon { width: 34px; height: 34px; }
            .calc-card-icon .svg-icon { width: 1rem; height: 1rem; }
            .calc-card-info h3 { font-size: 0.83rem; }
            .calc-card-info p { font-size: 0.7rem; }
            .why-grid { grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); gap: 10px; }
            .related-mini-grid { grid-template-columns: 1fr 1fr; }
            .search-modal { max-height: 75vh; margin: 0 6px; }
        }
        @media (max-width: 480px) {
            .hero-btns { flex-direction: column; align-items: center; }
            .trust-badges { gap: 6px; }
            .trust-badge { font-size: 0.72rem; padding: 5px 10px; }
            .cards-grid { grid-template-columns: 1fr 1fr; gap: 8px; }
            .calc-card { flex-direction: column; align-items: center; text-align: center; padding: 12px 10px; }
            .search-modal { max-height: 80vh; border-radius: var(--radius-lg); }
            .search-modal-header { padding: 10px 12px; }
            .search-results { padding: 4px; }
            .section-header h2 { font-size: 1.4rem; }
            .why-card { padding: 16px 12px; }
            .related-mini-grid { grid-template-columns: 1fr; }
        }