/* ==========================================================================
   MMM Framework - Complete Shared Styles
   Covers: index, about, technical-guide, variable-selection, 
           bayesian-workflow, causal-inference, faq
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Variables / Design Tokens
   -------------------------------------------------------------------------- */
:root {
    /* Colors */
    --color-primary: #8fa86a;
    --color-primary-dark: #6d8a4a;
    --color-accent: #6a8fa8;
    --color-accent-dark: #4a6d8a;
    --color-bg: #fafbf9;
    --color-bg-alt: #f0f2ed;
    --color-surface: #ffffff;
    --color-surface-elevated: #ffffff;
    --color-text: #2d3a2d;
    --color-text-muted: #5a6b5a;
    --color-border: #d4ddd4;
    --color-success: #6abf8a;
    --color-warning: #d4a86a;
    --color-danger: #c97067;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(45, 58, 45, 0.06);
    --shadow-md: 0 8px 24px rgba(45, 58, 45, 0.08);
    --shadow-lg: 0 16px 48px rgba(45, 58, 45, 0.12);

    /* Transitions */
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.7;
    font-size: 17px;
}

/* --------------------------------------------------------------------------
   Layout
   -------------------------------------------------------------------------- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    padding: 6rem 0;
}

.hidden {
    display: none;
}

/* --------------------------------------------------------------------------
   Navigation
   -------------------------------------------------------------------------- */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(250, 251, 249, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    padding: 1rem 0;
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: 'DM Serif Display', serif;
    font-size: 1.5rem;
    color: var(--color-primary-dark);
    text-decoration: none;
}

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

.nav-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-smooth);
}

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

/* Mobile menu button */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    margin: 5px 0;
    transition: var(--transition-smooth);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
footer {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: 3rem 0;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.9rem;
}

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

/* --------------------------------------------------------------------------
   Typography
   -------------------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
    font-family: 'DM Serif Display', serif;
    color: var(--color-text);
}

h1 { font-size: 2.8rem; }
h2 { font-size: 2rem; margin-bottom: 1.5rem; }
h3 { font-size: 1.3rem; margin: 2rem 0 1rem; }

p { margin-bottom: 1.25rem; }
p:last-child { margin-bottom: 0; }

.lead {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    max-width: 800px;
}

ul, ol {
    margin: 1rem 0 1rem 1.5rem;
}

li {
    margin-bottom: 0.5rem;
}

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: var(--transition-smooth);
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
}

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

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

.btn-white:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-outline-white {
    background: transparent;
    border: 2px solid rgba(255, 255, 255, 0.5);
    color: white;
}

.btn-outline-white:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: white;
}

/* --------------------------------------------------------------------------
   Section Headers
   -------------------------------------------------------------------------- */
.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-family: 'DM Serif Display', serif;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--color-text);
}

.section-header p {
    font-size: 1.2rem;
    color: var(--color-text-muted);
    max-width: 600px;
    margin: 0 auto;
}

/* --------------------------------------------------------------------------
   Hero Sections
   -------------------------------------------------------------------------- */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 6rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 80%;
    height: 150%;
    background: radial-gradient(ellipse at center, rgba(143, 168, 106, 0.08) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text {
    position: relative;
    z-index: 1;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(143, 168, 106, 0.1);
    border: 1px solid rgba(143, 168, 106, 0.3);
    padding: 0.5rem 1rem;
    border-radius: 100px;
    font-size: 0.85rem;
    color: var(--color-primary-dark);
    margin-bottom: 1.5rem;
}

.hero h1 {
    font-family: 'DM Serif Display', serif;
    font-size: 3.5rem;
    line-height: 1.15;
    margin-bottom: 1.5rem;
    color: var(--color-text);
}

.hero h1 span {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    margin-bottom: 2.5rem;
}

.hero-cta {
    display: flex;
    gap: 1rem;
}

.hero-visual {
    position: relative;
}

.hero-chart {
    background: var(--color-surface);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    padding: 2rem;
    border: 1px solid var(--color-border);
}

/* Simple hero (about, variable-selection pages) */
.hero.simple {
    min-height: auto;
    padding-top: 8rem;
    padding-bottom: 4rem;
    background: linear-gradient(180deg, var(--color-bg-alt) 0%, var(--color-bg) 100%);
}

.hero.simple::before {
    display: none;
}

.hero.simple .hero-content {
    display: block;
}

/* --------------------------------------------------------------------------
   Cards
   -------------------------------------------------------------------------- */
.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.5rem;
    transition: var(--transition-smooth);
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card h4 {
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.card p {
    color: var(--color-text-muted);
    font-size: 0.95rem;
    margin: 0;
}

.card .icon {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.card.success { border-left: 4px solid var(--color-success); }
.card.danger { border-left: 4px solid var(--color-danger); }
.card.warning { border-left: 4px solid var(--color-warning); }
.card.accent { border-left: 4px solid var(--color-accent); }

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

/* Principle cards (about page) */
.principle-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.principle-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.5rem;
    transition: var(--transition-smooth);
}

.principle-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.principle-card .icon {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.principle-card h4 {
    font-size: 1.15rem;
    margin-bottom: 0.75rem;
    color: var(--color-text);
}

.principle-card p {
    color: var(--color-text-muted);
    font-size: 0.95rem;
}

/* Model cards (index page) */
.model-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.model-card {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid var(--color-border);
    transition: var(--transition-smooth);
    cursor: pointer;
}

.model-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.model-icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, rgba(143, 168, 106, 0.1), rgba(106, 143, 168, 0.1));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.model-icon svg {
    width: 32px;
    height: 32px;
}

.model-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
}

.model-card .use-case {
    font-size: 0.9rem;
    color: var(--color-primary-dark);
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.model-card p {
    color: var(--color-text-muted);
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

.model-visual {
    margin-top: 1.5rem;
    background: var(--color-bg-alt);
    border-radius: 8px;
    padding: 1rem;
    min-height: 120px;
}

.learn-more {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    color: var(--color-primary);
    font-weight: 600;
    font-size: 0.9rem;
    text-decoration: none;
}

.learn-more:hover {
    text-decoration: underline;
}

/* Method cards (variable-selection, technical-guide) */
.method-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.method-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
    transition: var(--transition-smooth);
}

.method-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.method-card h4 {
    color: var(--color-primary-dark);
    margin-bottom: 0.5rem;
}

.method-card .use-for {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-bottom: 1rem;
}

.method-card .icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

/* --------------------------------------------------------------------------
   Callout Boxes
   -------------------------------------------------------------------------- */
.highlight-box {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-left: 4px solid var(--color-primary);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 2rem 0;
}

.highlight-box h4 {
    color: var(--color-primary-dark);
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.definition {
    background: rgba(106, 143, 168, 0.1);
    border-left: 4px solid var(--color-accent);
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    margin: 1.5rem 0;
}

.definition h4 {
    color: var(--color-accent-dark);
    margin-top: 0;
    margin-bottom: 0.5rem;
}

.warning, .warning-box {
    background: rgba(201, 112, 103, 0.08);
    border: 1px solid rgba(201, 112, 103, 0.3);
    border-left: 4px solid var(--color-danger);
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    margin: 1.5rem 0;
}

.warning h4, .warning-box h4 {
    color: var(--color-danger);
    margin-top: 0;
    margin-bottom: 0.5rem;
}

.note, .success-box {
    background: rgba(106, 191, 138, 0.1);
    border: 1px solid rgba(106, 191, 138, 0.3);
    border-left: 4px solid var(--color-success);
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    margin: 1.5rem 0;
}

.note h4, .success-box h4 {
    color: #3d8b5a;
    margin-top: 0;
    margin-bottom: 0.5rem;
}

.caution-box {
    background: rgba(212, 168, 106, 0.1);
    border: 1px solid rgba(212, 168, 106, 0.3);
    border-left: 4px solid var(--color-warning);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 2rem 0;
}

.caution-box h4 {
    color: #b8860b;
    margin-bottom: 0.75rem;
}

.info-box {
    background: rgba(106, 143, 168, 0.1);
    border: 1px solid rgba(106, 143, 168, 0.3);
    border-left: 4px solid var(--color-accent);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 2rem 0;
}

.info-box h4 {
    color: var(--color-accent-dark);
    margin-bottom: 0.75rem;
}

/* Rule box (causal-inference) */
.rule-box {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.rule-box h4 {
    margin-top: 0;
    color: var(--color-accent-dark);
}

.rule-box .rule-formula {
    background: var(--color-bg-alt);
    padding: 1rem;
    border-radius: 8px;
    margin: 1rem 0;
    font-size: 1.1rem;
    text-align: center;
}

/* --------------------------------------------------------------------------
   Code / Math
   -------------------------------------------------------------------------- */
pre {
    background: var(--color-bg-alt);
    padding: 1.5rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 1.5rem 0;
}

code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
}

p code, li code {
    background: var(--color-bg-alt);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
}

.math-block {
    background: var(--color-bg-alt);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
    overflow-x: auto;
    position: relative;
}

.equation-label {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* --------------------------------------------------------------------------
   Tables
   -------------------------------------------------------------------------- */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    background: var(--color-surface);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

th, td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

th {
    background: var(--color-bg-alt);
    font-weight: 600;
}

tbody tr:last-child td {
    border-bottom: none;
}

/* --------------------------------------------------------------------------
   Badges
   -------------------------------------------------------------------------- */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 600;
}

.badge-success {
    background: rgba(106, 191, 138, 0.15);
    color: #3d8b5a;
}

.badge-danger {
    background: rgba(201, 112, 103, 0.15);
    color: var(--color-danger);
}

.badge-warning {
    background: rgba(212, 168, 106, 0.15);
    color: #b8860b;
}

.prob-high {
    background: rgba(106, 191, 138, 0.15);
    color: #3d8b5a;
    padding: 0.25rem 0.75rem;
    border-radius: 100px;
    font-size: 0.85rem;
}

.prob-medium {
    background: rgba(212, 168, 106, 0.15);
    color: #b8860b;
    padding: 0.25rem 0.75rem;
    border-radius: 100px;
    font-size: 0.85rem;
}

.prob-low {
    background: rgba(201, 112, 103, 0.15);
    color: var(--color-danger);
    padding: 0.25rem 0.75rem;
    border-radius: 100px;
    font-size: 0.85rem;
}

/* Warning badge (index) */
.warning-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(201, 112, 103, 0.1);
    border: 1px solid rgba(201, 112, 103, 0.3);
    padding: 0.5rem 1rem;
    border-radius: 100px;
    font-size: 0.85rem;
    color: var(--color-danger);
    margin-bottom: 1rem;
}

/* Step badges (bayesian-workflow) */
.step-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 600;
    color: white;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.step-badge.check { background: var(--color-accent); }
.step-badge.iterate { background: var(--color-warning); }
.step-badge.diagnose { background: var(--color-danger); }

/* --------------------------------------------------------------------------
   Page Layout with Sidebar
   -------------------------------------------------------------------------- */
.page-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    max-width: 1400px;
    margin: 0 auto;
    padding-top: 5rem;
}

.sidebar {
    position: sticky;
    top: 5rem;
    height: calc(100vh - 5rem);
    overflow-y: auto;
    padding: 5rem 2rem;
    border-right: 1px solid var(--color-border);
    background: var(--color-bg);
}

.sidebar h3 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-bottom: 1rem;
    margin-top: 1.5rem;
    font-family: 'Source Sans 3', sans-serif;
}

.sidebar h3:first-child {
    margin-top: 0;
}

.sidebar-nav {
    list-style: none;
    margin: 0;
    padding: 0;
}

.sidebar-nav a {
    display: block;
    padding: 0.5rem 0;
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.95rem;
    transition: var(--transition-smooth);
    border-left: 2px solid transparent;
    padding-left: 1rem;
    margin-left: -1rem;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
    color: var(--color-primary);
    border-left-color: var(--color-primary);
}

.sidebar-nav .sub-item a {
    padding-left: 2rem;
    font-size: 0.9rem;
}

.main-content {
    padding: 3rem 4rem;
    max-width: 900px;
}

.main-content h1 {
    font-family: 'DM Serif Display', serif;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--color-text);
}

.main-content h2 {
    font-family: 'DM Serif Display', serif;
    font-size: 1.8rem;
    margin-top: 3rem;
    margin-bottom: 1rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
    color: var(--color-text);
}

.main-content h2:first-of-type {
    border-top: none;
    margin-top: 2rem;
}

.main-content h3 {
    font-size: 1.3rem;
    margin-top: 2rem;
    margin-bottom: 0.75rem;
    color: var(--color-text);
}

.main-content h4 {
    font-size: 1.1rem;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--color-text-muted);
}

.main-content .lead {
    font-size: 1.15rem;
    color: var(--color-text-muted);
    margin-bottom: 2rem;
}

/* --------------------------------------------------------------------------
   Problem Section (index)
   -------------------------------------------------------------------------- */
.problem-section {
    background: var(--color-bg-alt);
}

.problem-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 4rem;
    align-items: start;
}

.problem-content h3 {
    font-family: 'DM Serif Display', serif;
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
}

.problem-content p {
    color: var(--color-text-muted);
    margin-bottom: 1.5rem;
}

/* --------------------------------------------------------------------------
   Dartboard Demo (index)
   -------------------------------------------------------------------------- */
.dartboard-demo {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.dartboard-svg {
    width: 100%;
    max-width: 300px;
    margin: 0 auto;
    display: block;
}

.dartboard-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-top: 1.5rem;
}

.stat-item {
    text-align: center;
    padding: 0.75rem;
    background: var(--color-bg-alt);
    border-radius: 8px;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    display: block;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    font-family: 'JetBrains Mono', monospace;
}

.stat-value.accuracy {
    color: var(--color-danger);
}

.dartboard-explanation {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
}

.dartboard-explanation h4 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.dartboard-explanation p {
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

#punchline {
    margin-top: 1rem;
    padding: 1rem;
    background: rgba(201, 112, 103, 0.1);
    border-radius: 8px;
    font-weight: 600;
    color: var(--color-danger);
}

.restart-btn {
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition-smooth);
}

.restart-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* Dart animations */
.dart {
    animation: dartThrow 0.3s ease-out forwards;
}

.dart-miss {
    animation: dartFade 1s ease-out 0.3s forwards;
}

@keyframes dartThrow {
    from { opacity: 0; transform: scale(2); }
    to { opacity: 1; transform: scale(1); }
}

@keyframes dartFade {
    to { opacity: 0.15; }
}

/* --------------------------------------------------------------------------
   Models Section (index)
   -------------------------------------------------------------------------- */
.models-section {
    background: var(--color-bg);
}

/* --------------------------------------------------------------------------
   Feature Section (index)
   -------------------------------------------------------------------------- */
.feature-section {
    background: var(--color-bg-alt);
}

.feature-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.feature-content h3 {
    font-family: 'DM Serif Display', serif;
    font-size: 1.8rem;
    margin-bottom: 1rem;
}

.feature-content p {
    color: var(--color-text-muted);
    margin-bottom: 1.5rem;
}

.feature-visual {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
}

/* --------------------------------------------------------------------------
   Demo Section (index, variable-selection)
   -------------------------------------------------------------------------- */
.demo-section {
    background: var(--color-bg-alt);
}

.demo-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 3rem;
    align-items: start;
}

.demo-controls {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid var(--color-border);
}

.demo-controls h3 {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
}

.demo-container {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.demo-header {
    margin-bottom: 1.5rem;
}

.demo-header h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.demo-header p {
    color: var(--color-text-muted);
}

.demo-chart-area {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 1.5rem;
    border: 1px solid var(--color-border);
}

/* --------------------------------------------------------------------------
   Controls & Inputs
   -------------------------------------------------------------------------- */
.control-group {
    margin-bottom: 1.5rem;
}

.control-group label {
    display: block;
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-bottom: 0.5rem;
}

.control-group input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--color-bg-alt);
    outline: none;
    -webkit-appearance: none;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--color-primary);
    cursor: pointer;
}

.control-value {
    text-align: right;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    color: var(--color-primary-dark);
}

.control-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 1rem 0;
    flex-wrap: wrap;
}

.control-row label {
    font-weight: 500;
    min-width: 180px;
}

.control-row input[type="range"] {
    flex: 1;
    min-width: 200px;
}

.control-row .value {
    font-family: 'JetBrains Mono', monospace;
    background: var(--color-bg-alt);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    min-width: 60px;
    text-align: center;
}

/* Chart tabs */
.chart-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.chart-tab {
    padding: 0.5rem 1rem;
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition-smooth);
}

.chart-tab.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* --------------------------------------------------------------------------
   Charts & Diagrams
   -------------------------------------------------------------------------- */
.chart-container {
    height: 350px;
    background: var(--color-surface);
    border-radius: 12px;
    border: 1px solid var(--color-border);
    padding: 1rem;
    margin: 1.5rem 0;
}

.chart-container-lg {
    height: 400px;
}

.chart-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: 2rem 0;
}

.chart-box {
    background: var(--color-surface);
    border-radius: 12px;
    border: 1px solid var(--color-border);
    padding: 1.5rem;
}

.chart-box h4 {
    margin-bottom: 1rem;
    text-align: center;
    color: var(--color-text-muted);
}

/* Model diagram (technical-guide) */
.model-diagram {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 2rem;
    margin: 2rem 0;
}

/* DAG boxes (variable-selection, causal-inference) */
.dag-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: 2rem 0;
}

.dag-box {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid var(--color-border);
    text-align: center;
}

.dag-box h4 {
    margin-bottom: 1rem;
}

.dag-box.good {
    border-top: 4px solid var(--color-success);
}

.dag-box.bad {
    border-top: 4px solid var(--color-danger);
}

.dag-svg {
    width: 100%;
    max-width: 300px;
    height: 200px;
    margin: 0 auto;
}

/* Mermaid diagrams */
.dag-box .mermaid {
    background: transparent;
    margin: 0;
    padding: 0;
}

.dag-box .mermaid svg {
    max-width: 100%;
    height: auto;
}

/* Workflow diagram (bayesian-workflow) */
.workflow-diagram {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 2rem;
    margin: 2rem 0;
}

/* Interactive box (technical-guide) */
.interactive-box {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.interactive-box h4 {
    margin-top: 0;
    margin-bottom: 1rem;
    color: var(--color-text);
}

/* --------------------------------------------------------------------------
   Cross Effects Section (index)
   -------------------------------------------------------------------------- */
.cross-effects-section {
    background: var(--color-bg);
}

.cross-effects-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

.cross-effects-visual {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid var(--color-border);
}

.cross-effects-insight {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.insight-card {
    background: var(--color-surface);
    border-radius: 12px;
    padding: 1.5rem;
    border: 1px solid var(--color-border);
    margin-bottom: 1rem;
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.insight-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.insight-card strong {
    display: block;
    margin-bottom: 0.25rem;
}

/* --------------------------------------------------------------------------
   Interpretation Box (variable-selection)
   -------------------------------------------------------------------------- */
.interpretation-box {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--color-bg-alt);
    border-radius: 12px;
}

.interpretation-box h4 {
    margin-bottom: 1rem;
}

.interpretation-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.interpretation-list li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--color-border);
}

.interpretation-list li:last-child {
    border-bottom: none;
}

/* --------------------------------------------------------------------------
   Checklists (bayesian-workflow)
   -------------------------------------------------------------------------- */
.checklist {
    list-style: none;
    margin-left: 0;
    padding: 0;
}

.checklist li {
    padding-left: 1.5rem;
    position: relative;
    margin-bottom: 0.75rem;
}

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

.checklist li.warning-item::before {
    content: "⚠";
    color: var(--color-warning);
}

.checklist li.x-item::before {
    content: "✗";
    color: var(--color-danger);
}

/* Audience list (about) */
.audience-list {
    list-style: none;
    margin: 1.5rem 0;
    padding: 0;
}

.audience-list li {
    padding: 0.75rem 0;
    padding-left: 2rem;
    position: relative;
    border-bottom: 1px solid var(--color-border);
}

.audience-list li:last-child {
    border-bottom: none;
}

.audience-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--color-success);
    font-weight: bold;
}

/* --------------------------------------------------------------------------
   Interactive Section (variable-selection)
   -------------------------------------------------------------------------- */
.interactive-section {
    background: var(--color-surface);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid var(--color-border);
    margin: 2rem 0;
}

/* --------------------------------------------------------------------------
   CTA Section
   -------------------------------------------------------------------------- */
.cta-section {
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-accent-dark) 100%);
    color: white;
    padding: 5rem 0;
    text-align: center;
}

.cta-section h2 {
    font-family: 'DM Serif Display', serif;
    font-size: 2.5rem;
    color: white;
    margin-bottom: 1rem;
}

.cta-section p {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* --------------------------------------------------------------------------
   Grid Layouts
   -------------------------------------------------------------------------- */
.two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: 2rem 0;
}

.three-col {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin: 2rem 0;
}

/* --------------------------------------------------------------------------
   Animations
   -------------------------------------------------------------------------- */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.6s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
    .hero-content,
    .problem-grid,
    .demo-grid,
    .cross-effects-grid,
    .feature-grid {
        grid-template-columns: 1fr;
    }

    .model-cards {
        grid-template-columns: 1fr;
    }

    .page-layout {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: relative;
        top: auto;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--color-border);
    }

    .main-content {
        padding: 2rem;
    }

    .two-col,
    .three-col,
    .chart-grid,
    .dag-container {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 2.5rem;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-surface);
        padding: 1rem 2rem;
        border-bottom: 1px solid var(--color-border);
        gap: 0.5rem;
    }

    .hero {
        padding-top: 8rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

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

    .dartboard-stats {
        grid-template-columns: 1fr 1fr;
    }

    .footer-content {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }

    .footer-links {
        justify-content: center;
        gap: 1rem;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }

    section {
        padding: 4rem 0;
    }
}

.cta-section {
            background: linear-gradient(135deg, var(--color-primary-dark), var(--color-accent-dark));
            color: white;
            padding: 4rem 0;
            text-align: center;
            margin-top: 3rem;
        }
        .cta-section h2 {
            color: white;
            margin-bottom: 1rem;
        }
        .cta-section p {
            opacity: 0.9;
            margin-bottom: 2rem;
            max-width: 600px;
            margin-left: auto;
            margin-right: auto;
        }

        .contact-section {
            padding: 4rem 0;
            background: var(--color-bg);
        }
        .contact-card {
            background: var(--color-surface);
            border: 1px solid var(--color-border);
            border-radius: 16px;
            padding: 3rem;
            text-align: center;
            max-width: 650px;
            margin: 0 auto;
            box-shadow: var(--shadow-md);
        }
        .contact-icon {
            font-size: 3rem;
            margin-bottom: 1.5rem;
        }
        .contact-card h2 {
            padding-top: 0;
            margin-bottom: 1.25rem;
        }
        .contact-card p {
            color: var(--color-text-muted);
            max-width: 500px;
            margin-left: auto;
            margin-right: auto;
        }
        .contact-card .btn-primary {
            background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
            color: white;
            margin-top: 1.5rem;
            margin-bottom: 1.5rem;
        }
        .contact-card .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }
        .contact-note {
            font-size: 0.9rem;
            color: var(--color-text-muted);
            margin-bottom: 0;
        }
        .contact-note a {
            color: var(--color-primary-dark);
            text-decoration: none;
            font-weight: 500;
        }
        .contact-note a:hover {
            text-decoration: underline;
        }