body {
            font-family: 'SF Pro Text', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: var(--white);
            color: var(--purple-deep);
            line-height: 1.7;
        }

        .article-header {
            background: linear-gradient(135deg, var(--orange-main) 0%, var(--orange-dark) 100%);
            padding: 80px 40px;
            position: relative;
            overflow: hidden;
        }

        .article-header::before {
            content: '';
            position: absolute;
            top: -50%;
            right: -20%;
            width: 600px;
            height: 600px;
            background: radial-gradient(circle, hsl(41, 61%, 56%, 0.15) 0%, transparent 70%);
        }

        .header-inner {
            max-width: 800px;
            margin: 0 auto;
            position: relative;
            z-index: 1;
        }

        .breadcrumb {
            margin-bottom: 24px;
        }

        .breadcrumb a {
            color: hsl(0, 0%, 100%, 0.7);
            text-decoration: none;
            font-size: 14px;
        }

        .category-tag {
            display: inline-block;
            background: hsl(0, 0%, 100%, 0.2);
            color: var(--white);
            padding: 6px 16px;
            border-radius: 50px;
            font-size: 12px;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: 20px;
        }

        .article-header h1 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 44px;
            font-weight: 700;
            color: var(--white);
            margin-bottom: 20px;
            line-height: 1.15;
        }

        .article-meta {
            display: flex;
            align-items: center;
            gap: 24px;
            color: hsl(0, 0%, 100%, 0.8);
            font-size: 15px;
        }

        .article-meta svg {
            width: 18px;
            height: 18px;
            stroke: currentColor;
            stroke-width: 2;
            fill: none;
            margin-right: 6px;
            vertical-align: -3px;
        }

        .article-content {
            max-width: 760px;
            margin: 0 auto;
            padding: 60px 40px;
        }

        .article-content p {
            font-size: 18px;
            margin-bottom: 24px;
            color: hsl(240, 12%, 27%);
        }

        .article-content h2 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 32px;
            font-weight: 700;
            margin: 48px 0 20px;
            color: var(--purple-deep);
        }

        .article-content h3 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 24px;
            font-weight: 600;
            margin: 36px 0 16px;
            color: var(--purple-deep);
        }

        .lead-paragraph {
            font-size: 22px;
            color: var(--purple-deep);
            font-weight: 500;
            line-height: 1.6;
            margin-bottom: 32px;
            padding-bottom: 32px;
            border-bottom: 1px solid var(--gray-mid);
        }

        .callout {
            padding: 28px 32px;
            border-radius: 12px;
            margin: 32px 0;
        }

        .callout.stat {
            background: linear-gradient(135deg, hsl(262, 39%, 40%, 0.1) 0%, hsl(262, 39%, 40%, 0.05) 100%);
            border-left: 4px solid var(--purple-main);
        }

        .callout.warning {
            background: var(--red-light);
            border-left: 4px solid var(--red-main);
        }

        .callout.insight {
            background: var(--gray-light);
            border-left: 4px solid var(--gold-main);
        }

        .callout.success {
            background: var(--green-light);
            border-left: 4px solid var(--green-main);
        }

        .callout-label {
            font-size: 12px;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: 8px;
        }

        .callout.stat .callout-label { color: var(--purple-main); }
        .callout.warning .callout-label { color: var(--red-main); }
        .callout.insight .callout-label { color: var(--gold-main); }
        .callout.success .callout-label { color: var(--green-dark); }

        .callout p { margin-bottom: 0; font-size: 17px; }

        /* Key Equation */
        .key-equation {
            background: linear-gradient(135deg, var(--purple-deep) 0%, var(--purple-main) 100%);
            border-radius: 16px;
            padding: 40px;
            text-align: center;
            margin: 40px 0;
            position: relative;
            overflow: hidden;
        }

        .key-equation::before {
            content: '';
            position: absolute;
            top: -30%;
            right: -15%;
            width: 250px;
            height: 250px;
            background: radial-gradient(circle, hsl(41, 61%, 56%, 0.2) 0%, transparent 70%);
        }

        .key-equation .formula {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 28px;
            color: var(--white);
            position: relative;
            z-index: 1;
            line-height: 1.4;
        }

        .key-equation .formula .highlight {
            color: var(--gold-light);
            font-weight: 700;
        }

        .key-equation .explanation {
            color: var(--purple-light);
            font-size: 16px;
            margin-top: 16px;
            position: relative;
            z-index: 1;
        }

        /* Speed Decay Chart */
        .speed-decay {
            margin: 40px 0;
            padding: 32px;
            background: var(--gray-light);
            border-radius: 16px;
        }

        .speed-decay h4 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 20px;
            margin-bottom: 24px;
            color: var(--purple-deep);
            text-align: center;
        }

        .decay-bars {
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

        .decay-bar {
            display: flex;
            align-items: center;
            gap: 16px;
        }

        .decay-label {
            width: 90px;
            font-size: 14px;
            font-weight: 600;
            color: var(--gray-text);
            text-align: right;
        }

        .decay-fill {
            height: 40px;
            border-radius: 8px;
            display: flex;
            align-items: center;
            padding: 0 16px;
            color: var(--white);
            font-weight: 600;
            font-size: 14px;
        }

        .decay-fill.min-5 {
            width: 100%;
            background: linear-gradient(135deg, var(--green-main) 0%, hsl(123, 38%, 57%) 100%);
        }

        .decay-fill.min-10 {
            width: 80%;
            background: linear-gradient(135deg, hsl(123, 41%, 45%) 0%, var(--green-main) 100%);
        }

        .decay-fill.min-30 {
            width: 50%;
            background: linear-gradient(135deg, var(--gold-main) 0%, var(--gold-light) 100%);
            color: var(--purple-deep);
        }

        .decay-fill.hour-1 {
            width: 25%;
            background: linear-gradient(135deg, hsl(28, 80%, 52%) 0%, hsl(37, 90%, 51%) 100%);
        }

        .decay-fill.day-1 {
            width: 10%;
            background: linear-gradient(135deg, var(--red-main) 0%, hsl(0, 58%, 62%) 100%);
        }

        .decay-multiplier {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 18px;
            font-weight: 700;
            color: var(--purple-deep);
            min-width: 60px;
        }

        /* Follow-up Sequence */
        .sequence-timeline {
            margin: 40px 0;
            position: relative;
        }

        .sequence-timeline::before {
            content: '';
            position: absolute;
            left: 60px;
            top: 0;
            bottom: 0;
            width: 3px;
            background: linear-gradient(180deg, var(--orange-main) 0%, var(--gold-main) 50%, var(--purple-main) 100%);
        }

        .sequence-step {
            display: flex;
            gap: 24px;
            margin-bottom: 20px;
            position: relative;
        }

        .step-timing {
            width: 120px;
            flex-shrink: 0;
            text-align: right;
            padding-right: 30px;
        }

        .step-timing .time {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 20px;
            font-weight: 700;
            color: var(--orange-main);
        }

        .step-timing .label {
            font-size: 12px;
            color: var(--gray-text);
        }

        .step-marker {
            width: 20px;
            height: 20px;
            background: var(--white);
            border: 4px solid var(--orange-main);
            border-radius: 50%;
            position: absolute;
            left: 51px;
            top: 4px;
            z-index: 1;
        }

        .step-content {
            background: var(--white);
            border: 1px solid var(--gray-mid);
            border-radius: 12px;
            padding: 20px 24px;
            flex-grow: 1;
            margin-left: 30px;
        }

        .step-content h4 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 18px;
            margin-bottom: 8px;
            color: var(--purple-deep);
        }

        .step-content p {
            font-size: 15px;
            margin: 0;
            color: var(--gray-text);
        }

        .step-content .channel {
            display: inline-block;
            padding: 4px 10px;
            border-radius: 50px;
            font-size: 11px;
            font-weight: 600;
            text-transform: uppercase;
            margin-top: 12px;
        }

        .step-content .channel.text { background: var(--green-light); color: var(--green-dark); }
        .step-content .channel.email { background: hsl(205, 87%, 94%); color: hsl(212, 80%, 42%); }
        .step-content .channel.call { background: var(--orange-light); color: var(--orange-main); }

        /* Cost Comparison */
        .cost-comparison {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 24px;
            margin: 40px 0;
        }

        .cost-card {
            padding: 28px;
            border-radius: 16px;
            text-align: center;
        }

        .cost-card.high-cpl {
            background: var(--red-light);
            border: 1px solid hsl(0, 50%, 54%, 0.2);
        }

        .cost-card.low-cpl {
            background: var(--green-light);
            border: 1px solid hsl(122, 39%, 49%, 0.2);
        }

        .cost-card .label {
            font-size: 12px;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 0.5px;
            margin-bottom: 16px;
        }

        .cost-card.high-cpl .label { color: var(--red-main); }
        .cost-card.low-cpl .label { color: var(--green-dark); }

        .cost-card .conversion {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 48px;
            font-weight: 700;
            margin-bottom: 8px;
        }

        .cost-card.high-cpl .conversion { color: var(--red-main); }
        .cost-card.low-cpl .conversion { color: var(--green-dark); }

        .cost-card .conversion-label {
            font-size: 15px;
            color: var(--gray-text);
            margin-bottom: 20px;
        }

        .cost-card .cpl {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 28px;
            font-weight: 700;
            margin-bottom: 4px;
        }

        .cost-card.high-cpl .cpl { color: var(--red-main); }
        .cost-card.low-cpl .cpl { color: var(--green-dark); }

        .cost-card .cpl-label {
            font-size: 13px;
            color: var(--gray-text);
        }

        /* Lead Stages */
        .lead-stages {
            margin: 40px 0;
        }

        .stage-row {
            display: flex;
            gap: 16px;
            margin-bottom: 16px;
            padding: 20px 24px;
            background: var(--gray-light);
            border-radius: 12px;
            align-items: center;
        }

        .stage-name {
            width: 120px;
            flex-shrink: 0;
        }

        .stage-name .name {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 16px;
            font-weight: 600;
            color: var(--purple-deep);
        }

        .stage-name .desc {
            font-size: 12px;
            color: var(--gray-text);
        }

        .stage-bar-container {
            flex-grow: 1;
            height: 24px;
            background: var(--gray-mid);
            border-radius: 12px;
            overflow: hidden;
        }

        .stage-bar {
            height: 100%;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: flex-end;
            padding-right: 12px;
            font-size: 12px;
            font-weight: 600;
            color: var(--white);
        }

        .stage-bar.hot { width: 100%; background: var(--green-main); }
        .stage-bar.warm { width: 60%; background: var(--gold-main); color: var(--purple-deep); }
        .stage-bar.cool { width: 30%; background: hsl(200, 16%, 62%); }
        .stage-bar.cold { width: 10%; background: var(--gray-text); }

        /* Data Table */
        .data-table {
            width: 100%;
            border-collapse: collapse;
            margin: 32px 0;
            font-size: 15px;
        }

        .data-table th {
            background: var(--gray-light);
            padding: 14px 16px;
            text-align: left;
            font-weight: 600;
            border-bottom: 2px solid var(--gray-mid);
        }

        .data-table td {
            padding: 14px 16px;
            border-bottom: 1px solid var(--gray-mid);
        }

        .data-table .highlight {
            background: var(--green-light);
            font-weight: 600;
        }

        /* CTA Section */
        .cta-section {
            background: linear-gradient(135deg, var(--purple-deep) 0%, var(--purple-main) 100%);
            border-radius: 20px;
            padding: 50px;
            text-align: center;
            margin: 48px 0;
            position: relative;
            overflow: hidden;
        }

        .cta-section::before {
            content: '';
            position: absolute;
            top: -50%;
            right: -20%;
            width: 300px;
            height: 300px;
            background: radial-gradient(circle, hsl(41, 61%, 56%, 0.15) 0%, transparent 70%);
        }

        .cta-section h3 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 28px;
            color: var(--white);
            margin-bottom: 12px;
            position: relative;
            z-index: 1;
        }

        .cta-section p {
            color: var(--purple-light);
            margin-bottom: 24px;
            font-size: 17px;
            position: relative;
            z-index: 1;
        }

        .cta-button {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            background: linear-gradient(135deg, var(--gold-main) 0%, var(--gold-light) 100%);
            color: var(--purple-deep);
            padding: 16px 32px;
            border-radius: 50px;
            font-size: 16px;
            font-weight: 600;
            text-decoration: none;
            position: relative;
            z-index: 1;
            transition: transform 0.2s;
        }

        .cta-button:hover { transform: translateY(-2px); }

        .cta-button svg {
            width: 20px;
            height: 20px;
            stroke: currentColor;
            stroke-width: 2.5;
            fill: none;
        }

        /* Related Articles */
        .related-section {
            background: var(--gray-light);
            padding: 60px 40px;
        }

        .related-inner {
            max-width: 1000px;
            margin: 0 auto;
        }

        .related-section h3 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 24px;
            margin-bottom: 24px;
            text-align: center;
        }

        .related-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }

        .related-card {
            background: var(--white);
            border-radius: 12px;
            padding: 24px;
            text-decoration: none;
            transition: transform 0.2s, box-shadow 0.2s;
        }

        .related-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 12px 40px hsl(261, 49%, 21%, 0.1);
        }

        .related-card .tag {
            font-size: 11px;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 0.5px;
            margin-bottom: 8px;
        }

        .related-card.retention .tag { color: var(--purple-main); }
        .related-card.recovery .tag { color: hsl(123, 46%, 34%); }
        .related-card.reactivation .tag { color: hsl(212, 80%, 42%); }

        .related-card h4 {
            font-family: 'SF Pro Display', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            font-size: 17px;
            color: var(--purple-deep);
            line-height: 1.3;
        }

        @media (max-width: 768px) {
            .cost-comparison { grid-template-columns: 1fr; }
            .related-grid { grid-template-columns: 1fr; }
            .sequence-timeline::before { left: 20px; }
            .step-timing { width: 60px; padding-right: 10px; }
            .step-marker { left: 11px; }
            .step-content { margin-left: 10px; }
        }