/* --- CSS Custom Properties --- */
:root {
    /* Color Palette */
    --color-slate-900: #0F172A;
    --color-deep-slate: #1E293B; /* Primary */
    --color-slate-700: #334155;
    --color-slate-500: #64748B;
    --color-slate-100: #F1F5F9;
    --color-white: #FFFFFF;
    
    --color-electric-blue: #2563EB; /* Secondary / Action */
    --color-electric-blue-hover: #1D4ED8;
    
    --color-emerald-green: #10B981; /* Accent */

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

    /* Type Scale */
    --text-xs: 0.75rem;   /* 12px */
    --text-sm: 0.875rem;  /* 14px */
    --text-base: 1rem;    /* 16px */
    --text-lg: 1.125rem;  /* 18px */
    --text-xl: 1.25rem;   /* 20px */
    --text-2xl: 1.5rem;   /* 24px */
    --text-3xl: 1.875rem; /* 30px */
    --text-4xl: 2.25rem;  /* 36px */
    --text-5xl: 3rem;     /* 48px */

    /* Spacing Scale */
    --space-1: 0.25rem;  /* 4px */
    --space-2: 0.5rem;   /* 8px */
    --space-4: 1rem;     /* 16px */
    --space-6: 1.5rem;   /* 24px */
    --space-8: 2rem;     /* 32px */
    --space-12: 3rem;    /* 48px */
    --space-16: 4rem;    /* 64px */
    --space-24: 6rem;    /* 96px */

    /* Borders & Shadows */
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

/* --- Reset & Base Styles --- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-primary);
    background-color: var(--color-white);
    color: var(--color-deep-slate);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-primary);
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-slate-900);
    margin-bottom: var(--space-4);
}

p {
    margin-bottom: var(--space-4);
    color: var(--color-slate-700);
}

a {
    color: var(--color-electric-blue);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--color-electric-blue-hover);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.text-center {
    text-align: center;
}

.section-title {
    text-align: center;
    font-size: var(--text-3xl);
    margin-bottom: var(--space-12);
}

/* --- Accessibility --- */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-electric-blue);
    color: white;
    padding: 8px;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}

*:focus-visible {
    outline: 2px solid var(--color-electric-blue);
    outline-offset: 2px;
}

/* --- Buttons --- */
.btn {
    display: inline-block;
    padding: var(--space-2) var(--space-6);
    border-radius: var(--radius-md);
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    font-family: var(--font-primary);
}

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

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

.btn-large {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-lg);
}

/* --- Header --- */
.site-header {
    border-bottom: 1px solid var(--color-slate-100);
    background-color: var(--color-white);
    position: sticky;
    top: 0;
    z-index: 50;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo-image {
    height: 32px;
}

.primary-nav ul {
    list-style: none;
    display: flex;
    gap: var(--space-6);
}

.primary-nav a {
    color: var(--color-slate-700);
    font-weight: 500;
}

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

/* --- Hero Section --- */
.hero {
    padding: var(--space-16) 0;
    background-color: var(--color-slate-100);
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-12);
    align-items: center;
}

.hero h1 {
    font-size: var(--text-5xl);
    letter-spacing: -0.02em;
}

.subheadline {
    font-size: var(--text-xl);
    margin-bottom: var(--space-8);
}

.hero-microcopy {
    font-size: var(--text-sm);
    color: var(--color-slate-500);
    margin-top: var(--space-2);
}

.dashboard-mockup {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-slate-100);
}

/* --- Social Proof --- */
.social-proof {
    padding: var(--space-8) 0;
    border-bottom: 1px solid var(--color-slate-100);
    text-align: center;
}

.social-proof .caption {
    font-size: var(--text-sm);
    color: var(--color-slate-500);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-4);
}

.logos-placeholder {
    display: flex;
    justify-content: center;
    gap: var(--space-12);
    flex-wrap: wrap;
}

.esp-logo {
    font-family: var(--font-mono);
    font-weight: 500;
    color: var(--color-slate-500);
    font-size: var(--text-lg);
}

/* --- Problem / Solution --- */
.problem-solution {
    padding: var(--space-24) 0;
    background-color: var(--color-white);
}

.problem-text {
    max-width: 800px;
    margin: 0 auto;
    font-size: var(--text-lg);
}

.problem-text h2 {
    font-size: var(--text-4xl);
    margin-bottom: var(--space-6);
}

/* --- Features --- */
.features {
    padding: var(--space-24) 0;
    background-color: var(--color-slate-100);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-8);
}

.feature-card {
    background: var(--color-white);
    padding: var(--space-8);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.feature-icon {
    height: 48px;
    margin-bottom: var(--space-6);
}

.feature-card h3 {
    font-size: var(--text-xl);
}

/* --- How It Works --- */
.how-it-works {
    padding: var(--space-24) 0;
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-8);
}

.step {
    position: relative;
    padding-top: var(--space-8);
}

.step-number {
    font-family: var(--font-mono);
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--color-electric-blue);
    margin-bottom: var(--space-4);
}

.step h3 {
    font-size: var(--text-xl);
}

/* --- Pricing --- */
.pricing {
    padding: var(--space-24) 0;
    background-color: var(--color-slate-900);
    color: var(--color-white);
}

.pricing .section-title {
    color: var(--color-white);
}

.pricing-cards {
    display: flex;
    justify-content: center;
}

.pricing-card {
    background-color: var(--color-deep-slate);
    border: 1px solid var(--color-slate-700);
    border-radius: var(--radius-lg);
    padding: var(--space-8);
    max-width: 400px;
    width: 100%;
    text-align: center;
}

.pricing-card h3 {
    color: var(--color-white);
    font-size: var(--text-2xl);
}

.pricing-card .price {
    font-family: var(--font-mono);
    font-size: var(--text-4xl);
    font-weight: 700;
    color: var(--color-emerald-green);
    margin: var(--space-4) 0;
}

.pricing-desc {
    color: var(--color-slate-100);
    margin-bottom: var(--space-6);
}

.pricing-features {
    list-style: none;
    margin-bottom: var(--space-8);
    text-align: left;
}

.pricing-features li {
    padding: var(--space-2) 0;
    border-bottom: 1px solid var(--color-slate-700);
    color: var(--color-slate-100);
}

.pricing-features li:last-child {
    border-bottom: none;
}

.pricing-note {
    text-align: center;
    color: var(--color-slate-500);
    margin-top: var(--space-8);
    font-size: var(--text-sm);
}

/* --- FAQ --- */
.faq {
    padding: var(--space-24) 0;
    background-color: var(--color-white);
}

.faq-grid {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--color-slate-100);
    padding: var(--space-6) 0;
}

.faq-item summary {
    font-size: var(--text-xl);
    font-weight: 600;
    cursor: pointer;
    list-style: none;
    position: relative;
    padding-right: var(--space-6);
    color: var(--color-slate-900);
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    font-size: var(--text-2xl);
    color: var(--color-electric-blue);
}

.faq-item[open] summary::after {
    content: '-';
}

.faq-answer {
    padding-top: var(--space-4);
    color: var(--color-slate-700);
}

/* --- Secondary CTA --- */
.secondary-cta {
    padding: var(--space-24) 0;
    background-color: var(--color-electric-blue);
    color: var(--color-white);
}

.secondary-cta h2 {
    color: var(--color-white);
    font-size: var(--text-4xl);
}

.secondary-cta p {
    color: rgba(255, 255, 255, 0.9);
    font-size: var(--text-lg);
    margin-bottom: var(--space-8);
}

.signup-form {
    display: flex;
    justify-content: center;
    gap: var(--space-4);
    max-width: 500px;
    margin: 0 auto;
}

.signup-form input {
    flex: 1;
    padding: var(--space-4);
    border: none;
    border-radius: var(--radius-md);
    font-family: var(--font-primary);
    font-size: var(--text-base);
}

.signup-form .btn {
    background-color: var(--color-deep-slate);
    border: 1px solid var(--color-deep-slate);
}

.signup-form .btn:hover {
    background-color: var(--color-slate-900);
}

/* --- Footer --- */
.site-footer {
    background-color: var(--color-slate-900);
    color: var(--color-slate-100);
    padding: var(--space-16) 0 var(--space-6);
}

.footer-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: var(--space-12);
    margin-bottom: var(--space-12);
}

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

.footer-logo {
    height: 32px;
    margin-bottom: var(--space-4);
    filter: brightness(0) invert(1);
}

.footer-brand .tagline {
    color: var(--color-slate-500);
}

.footer-links {
    display: flex;
    gap: var(--space-16);
    flex-wrap: wrap;
}

.link-column h4 {
    color: var(--color-white);
    margin-bottom: var(--space-4);
}

.link-column ul {
    list-style: none;
}

.link-column li {
    margin-bottom: var(--space-2);
}

.link-column a {
    color: var(--color-slate-500);
}

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

.footer-bottom {
    border-top: 1px solid var(--color-slate-700);
    padding-top: var(--space-6);
    text-align: center;
    color: var(--color-slate-500);
    font-size: var(--text-sm);
}

/* --- Responsive --- */
@media (max-width: 768px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero h1 {
        font-size: var(--text-4xl);
    }
    
    .primary-nav {
        display: none; /* Hide nav on mobile for simplicity in MVP, or implement a burger menu later */
    }
    
    .signup-form {
        flex-direction: column;
    }
    
    .footer-links {
        gap: var(--space-8);
    }
}