:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #3b82f6;
    --secondary-color: #0ea5e9;
    --accent-color: #f59e0b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --background: #ffffff;
    --background-alt: #f8fafc;
    --surface: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border: #e2e8f0;
    --shadow: rgba(15, 23, 42, 0.1);
    --shadow-lg: rgba(15, 23, 42, 0.15);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--background);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.navbar {
    background: var(--surface);
    box-shadow: 0 1px 3px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.nav-brand h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 700;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s;
    font-size: 0.95rem;
}

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

.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero-title {
    font-size: 3rem;
    margin-bottom: 1rem;
    font-weight: 800;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 3rem;
    opacity: 0.95;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.stat-card {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-card h3 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.stat-card p {
    font-size: 1rem;
    opacity: 0.9;
}

.section {
    padding: 5rem 0;
}

.section-alt {
    background: var(--background-alt);
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-align: center;
    color: var(--text-primary);
    font-weight: 700;
}

.section-intro {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 3rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.content-card {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    border: 1px solid var(--border);
    transition: transform 0.3s, box-shadow 0.3s;
}

.content-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px var(--shadow-lg);
}

.content-card .icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.content-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
    font-weight: 600;
}

.content-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.benefits-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    margin-top: 3rem;
}

.benefit-item {
    display: flex;
    gap: 2rem;
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    border-left: 4px solid var(--primary-color);
}

.benefit-number {
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary-color);
    opacity: 0.2;
    min-width: 80px;
}

.benefit-content h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-weight: 600;
}

.benefit-content p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.benefit-content ul {
    list-style: none;
    padding-left: 0;
}

.benefit-content ul li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: 1.5rem;
}

.benefit-content ul li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

.chart-container {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    margin: 3rem 0;
    border: 1px solid var(--border);
}

.chart-container h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.data-table-container {
    margin: 3rem 0;
    overflow-x: auto;
}

.data-table-container h3 {
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.data-table {
    width: 100%;
    background: var(--surface);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 1px 3px var(--shadow);
    border-collapse: collapse;
}

.data-table thead {
    background: var(--primary-color);
    color: white;
}

.data-table th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.data-table td {
    padding: 1rem;
    border-bottom: 1px solid var(--border);
}

.data-table tbody tr:hover {
    background: var(--background-alt);
}

.data-table tbody tr.positive td:last-child {
    color: var(--success-color);
    font-weight: 600;
    font-size: 1.1rem;
}

.table-note {
    margin-top: 1rem;
    color: var(--text-muted);
    font-size: 0.9rem;
    font-style: italic;
}

.insight-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.insight-card {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px var(--shadow-lg);
}

.insight-card h4 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.insight-card p {
    line-height: 1.7;
    opacity: 0.95;
}

.calculator-container {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    margin: 2rem 0;
    border: 1px solid var(--border);
}

.calculator-inputs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.input-group {
    display: flex;
    flex-direction: column;
}

.input-group label {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
}

.input-group input,
.input-group select {
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--background);
    color: var(--text-primary);
    transition: border-color 0.3s;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn-calculate {
    padding: 0.75rem 2rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
    align-self: end;
}

.btn-calculate:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-calculate:active {
    transform: translateY(0);
}

.calculator-results {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    padding: 2rem;
    background: var(--background-alt);
    border-radius: 8px;
}

.result-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.result-label {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 500;
}

.result-value {
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 700;
}

.result-item.highlight .result-value {
    color: var(--success-color);
    font-size: 2rem;
}

.comparison-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.comparison-card {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    border: 1px solid var(--border);
}

.comparison-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    text-align: center;
    font-weight: 600;
}

.pros-cons {
    margin-bottom: 1.5rem;
}

.pros,
.cons {
    margin-bottom: 1.5rem;
}

.pros h4 {
    color: var(--success-color);
    margin-bottom: 0.75rem;
    font-weight: 600;
}

.cons h4 {
    color: var(--danger-color);
    margin-bottom: 0.75rem;
    font-weight: 600;
}

.pros ul,
.cons ul {
    list-style: none;
    padding-left: 0;
}

.pros ul li,
.cons ul li {
    padding: 0.4rem 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
    padding-left: 1.25rem;
    position: relative;
}

.pros ul li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--success-color);
}

.cons ul li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--danger-color);
}

.recommendation {
    text-align: center;
    padding: 1rem;
    background: var(--background-alt);
    border-radius: 8px;
    font-weight: 600;
    color: var(--text-primary);
}

.comparison-chart-container {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    margin-top: 3rem;
    border: 1px solid var(--border);
}

.comparison-chart-container h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.getting-started {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.step {
    text-align: center;
    padding: 2rem;
    background: var(--surface);
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
    border: 1px solid var(--border);
}

.step-number {
    display: inline-block;
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    line-height: 60px;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.step h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-weight: 600;
}

.step p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.warning-box {
    background: #fef3c7;
    border-left: 4px solid var(--accent-color);
    padding: 2rem;
    border-radius: 12px;
    margin-top: 3rem;
}

.warning-box h3 {
    color: #92400e;
    margin-bottom: 1rem;
    font-weight: 600;
}

.warning-box p {
    color: #78350f;
    margin-bottom: 1rem;
    line-height: 1.7;
}

.warning-box ul {
    list-style: none;
    padding-left: 0;
}

.warning-box ul li {
    color: #78350f;
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.warning-box ul li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-weight: bold;
}

.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    font-weight: 600;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.7;
    font-size: 0.9rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: var(--primary-light);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 0.5rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .benefit-item {
        flex-direction: column;
    }

    .benefit-number {
        font-size: 2rem;
        min-width: auto;
    }

    .calculator-inputs {
        grid-template-columns: 1fr;
    }

    .data-table {
        font-size: 0.85rem;
    }

    .data-table th,
    .data-table td {
        padding: 0.75rem 0.5rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.5rem;
    }

    .container {
        padding: 0 15px;
    }

    .section {
        padding: 3rem 0;
    }
}