/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors - matching Correlate brand */
    --color-primary: #2563EB;
    --color-primary-dark: #1D4ED8;
    --color-secondary: #06B6D4;
    --color-accent: #9333EA;

    --color-gray-50: #F9FAFB;
    --color-gray-100: #F3F4F6;
    --color-gray-200: #E5E7EB;
    --color-gray-300: #D1D5DB;
    --color-gray-400: #9CA3AF;
    --color-gray-500: #6B7280;
    --color-gray-600: #4B5563;
    --color-gray-700: #374151;
    --color-gray-800: #1F2937;
    --color-gray-900: #111827;

    --color-white: #FFFFFF;
    --color-black: #000000;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    --font-mono: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', monospace;

    /* Spacing */
    --spacing-unit: 8px;
    --container-width: 1200px;

    /* Effects */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);

    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-gray-900);
    background: var(--color-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 calc(var(--spacing-unit) * 3);
}

/* Navigation */
.nav {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-gray-200);
    z-index: 100;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: calc(var(--spacing-unit) * 2) 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 1.5);
    font-weight: 600;
    font-size: 20px;
    color: var(--color-gray-900);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: calc(var(--spacing-unit) * 4);
    align-items: center;
}

.nav-links a {
    color: var(--color-gray-600);
    text-decoration: none;
    font-weight: 500;
    font-size: 15px;
    transition: color 0.2s;
}

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

.nav-link-secondary {
    color: var(--color-gray-500) !important;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: calc(var(--spacing-unit) * 1.5) calc(var(--spacing-unit) * 3);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 15px;
    text-decoration: none;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--color-primary);
    color: var(--color-white);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--color-gray-100);
    color: var(--color-gray-900);
}

.btn-secondary:hover {
    background: var(--color-gray-200);
}

.btn-large {
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 4);
    font-size: 16px;
}

.btn-block {
    display: block;
    width: 100%;
    text-align: center;
}

/* Hero Section */
.hero {
    padding: calc(var(--spacing-unit) * 8) 0 calc(var(--spacing-unit) * 10);
    background: linear-gradient(135deg, var(--color-gray-50) 0%, var(--color-white) 100%);
    min-height: calc(100vh - 80px);
    display: flex;
    align-items: center;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto calc(var(--spacing-unit) * 4);
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.1;
    color: var(--color-gray-900);
    margin-bottom: calc(var(--spacing-unit) * 3);
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 22px;
    color: var(--color-gray-600);
    margin-bottom: calc(var(--spacing-unit) * 5);
    line-height: 1.5;
}

.hero-cta {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
    justify-content: center;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.hero-note {
    font-size: 14px;
    color: var(--color-gray-500);
}

.hero-image {
    max-width: 1000px;
    margin: 0 auto;
}

.hero-screenshot {
    width: 100%;
    max-height: 500px;
    object-fit: contain;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
}

/* Screenshot Placeholder */
.screenshot-placeholder {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    border-radius: var(--radius-xl);
    padding: calc(var(--spacing-unit) * 3);
    box-shadow: var(--shadow-xl);
}

.screenshot-window {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 25px 50px -12px rgb(0 0 0 / 0.25);
}

.window-controls {
    display: flex;
    gap: calc(var(--spacing-unit) * 1);
    padding: calc(var(--spacing-unit) * 2);
    background: var(--color-gray-100);
}

.window-controls span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--color-gray-300);
}

.window-content {
    padding: calc(var(--spacing-unit) * 4);
    height: 400px;
    background: var(--color-gray-50);
}

.timeline-viz,
.correlation-results {
    height: 45%;
    background: var(--color-white);
    border-radius: var(--radius-md);
    margin-bottom: calc(var(--spacing-unit) * 2);
    box-shadow: var(--shadow-sm);
}

/* Problem Section */
.problem {
    padding: calc(var(--spacing-unit) * 15) 0;
}

.section-title {
    font-size: 42px;
    font-weight: 700;
    text-align: center;
    margin-bottom: calc(var(--spacing-unit) * 8);
    color: var(--color-gray-900);
    letter-spacing: -0.01em;
}

.section-subtitle {
    font-size: 20px;
    text-align: center;
    color: var(--color-gray-600);
    margin-top: calc(var(--spacing-unit) * -4);
    margin-bottom: calc(var(--spacing-unit) * 8);
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: calc(var(--spacing-unit) * 4);
}

.problem-card {
    text-align: center;
    padding: calc(var(--spacing-unit) * 4);
}

.problem-icon {
    font-size: 48px;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.problem-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--color-gray-900);
}

.problem-card p {
    color: var(--color-gray-600);
    line-height: 1.6;
}

/* Features Section */
.features {
    padding: calc(var(--spacing-unit) * 15) 0;
    background: var(--color-gray-50);
}

.feature-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: calc(var(--spacing-unit) * 8);
    align-items: center;
    margin-bottom: calc(var(--spacing-unit) * 12);
}

.feature-row-reverse {
    direction: rtl;
}

.feature-row-reverse > * {
    direction: ltr;
}

.feature-badge {
    display: inline-block;
    padding: calc(var(--spacing-unit) * 1) calc(var(--spacing-unit) * 2);
    background: var(--color-primary);
    color: var(--color-white);
    border-radius: calc(var(--radius-sm) * 2);
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.feature-content h3 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--color-gray-900);
}

.feature-content p {
    font-size: 18px;
    color: var(--color-gray-600);
    line-height: 1.7;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.feature-list {
    list-style: none;
}

.feature-list li {
    padding: calc(var(--spacing-unit) * 1.5) 0;
    padding-left: calc(var(--spacing-unit) * 4);
    position: relative;
    color: var(--color-gray-700);
}

.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: 700;
}

.feature-visual {
    height: 400px;
}

.feature-visual img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.visual-placeholder {
    height: 100%;
    background: linear-gradient(135deg, var(--color-gray-100) 0%, var(--color-gray-200) 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray-400);
    font-weight: 600;
    font-size: 18px;
    box-shadow: var(--shadow-md);
}

/* Pricing Section */
.pricing {
    padding: calc(var(--spacing-unit) * 15) 0;
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: calc(var(--spacing-unit) * 4);
    max-width: 1000px;
    margin: 0 auto;
}

.pricing-card {
    background: var(--color-white);
    border: 2px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: calc(var(--spacing-unit) * 5);
    position: relative;
}

.pricing-card-featured {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-xl);
    transform: scale(1.05);
}

.pricing-badge {
    position: absolute;
    top: calc(var(--spacing-unit) * -2);
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-primary);
    color: var(--color-white);
    padding: calc(var(--spacing-unit) * 1) calc(var(--spacing-unit) * 3);
    border-radius: calc(var(--radius-sm) * 2);
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
}

.pricing-tier {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--color-gray-900);
}

.pricing-price {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.price-amount {
    font-size: 48px;
    font-weight: 800;
    color: var(--color-gray-900);
}

.price-period {
    font-size: 18px;
    color: var(--color-gray-500);
}

.pricing-description {
    color: var(--color-gray-600);
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding-bottom: calc(var(--spacing-unit) * 4);
    border-bottom: 1px solid var(--color-gray-200);
}

.pricing-features {
    list-style: none;
    margin-bottom: calc(var(--spacing-unit) * 4);
}

.pricing-features li {
    padding: calc(var(--spacing-unit) * 1.5) 0;
    color: var(--color-gray-700);
    padding-left: calc(var(--spacing-unit) * 4);
    position: relative;
}

.pricing-features li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: 700;
}

/* FAQ Section */
.faq {
    padding: calc(var(--spacing-unit) * 15) 0;
    background: var(--color-gray-50);
}

.faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: calc(var(--spacing-unit) * 4);
    max-width: 900px;
    margin: 0 auto;
}

.faq-item h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--color-gray-900);
}

.faq-item p {
    color: var(--color-gray-600);
    line-height: 1.7;
}

/* CTA Section */
.cta {
    padding: calc(var(--spacing-unit) * 15) 0;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: var(--color-white);
}

.cta-content {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.cta-content h2 {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.cta-content p {
    font-size: 20px;
    margin-bottom: calc(var(--spacing-unit) * 5);
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
    justify-content: center;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.cta-buttons .btn-primary {
    background: var(--color-white);
    color: var(--color-primary);
}

.cta-buttons .btn-primary:hover {
    background: var(--color-gray-100);
}

.cta-note {
    font-size: 14px;
    opacity: 0.8;
}

/* Footer */
.footer {
    background: var(--color-gray-900);
    color: var(--color-gray-400);
    padding: calc(var(--spacing-unit) * 8) 0 calc(var(--spacing-unit) * 4);
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: calc(var(--spacing-unit) * 6);
    margin-bottom: calc(var(--spacing-unit) * 6);
}

.footer-brand {
    max-width: 300px;
}

.footer-brand p {
    margin-top: calc(var(--spacing-unit) * 2);
    line-height: 1.6;
}

.footer-column h4 {
    color: var(--color-white);
    font-weight: 600;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.footer-column a {
    display: block;
    color: var(--color-gray-400);
    text-decoration: none;
    padding: calc(var(--spacing-unit) * 1) 0;
    transition: color 0.2s;
}

.footer-column a:hover {
    color: var(--color-white);
}

.footer-bottom {
    border-top: 1px solid var(--color-gray-800);
    padding-top: calc(var(--spacing-unit) * 4);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-social {
    display: flex;
    gap: calc(var(--spacing-unit) * 3);
}

.footer-social a {
    color: var(--color-gray-400);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-social a:hover {
    color: var(--color-white);
}

/* Email Signup */
.email-signup {
    margin-top: calc(var(--spacing-unit) * 8);
    padding-top: calc(var(--spacing-unit) * 6);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.email-signup-text {
    font-size: 16px;
    color: var(--color-white);
    margin-bottom: calc(var(--spacing-unit) * 3);
    opacity: 0.9;
}

.email-form {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
    max-width: 500px;
    margin: 0 auto;
}

.email-input {
    flex: 1;
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 3);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-md);
    font-size: 16px;
    background: rgba(255, 255, 255, 0.1);
    color: var(--color-white);
    transition: all 0.2s;
}

.email-input::placeholder {
    color: rgba(255, 255, 255, 0.5);
}

.email-input:focus {
    outline: none;
    border-color: var(--color-white);
    background: rgba(255, 255, 255, 0.15);
}

.form-message {
    margin-top: calc(var(--spacing-unit) * 2);
    font-size: 14px;
    color: var(--color-white);
    text-align: center;
}

.form-message.success {
    color: #10b981;
}

.form-message.error {
    color: #ef4444;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 18px;
    }

    .hero-cta {
        flex-direction: column;
    }

    .section-title {
        font-size: 32px;
    }

    .feature-row {
        grid-template-columns: 1fr;
    }

    .feature-row-reverse {
        direction: ltr;
    }

    .pricing-card-featured {
        transform: none;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }

    .nav-links {
        display: none;
    }

    .email-form {
        flex-direction: column;
    }

    .email-input {
        width: 100%;
    }
}