/* ===================================
   CSS Custom Properties (Theme System)
   =================================== */

:root {
    /* Colors - Light Theme */
    --color-text: #1a1a1a;
    --color-text-light: #4a4a4a;
    --color-background: #fafafa;
    --color-surface: #ffffff;
    --color-surface-alt: #f5f5f5;

    /* Primary Accent */
    --color-accent: #2563eb;
    --color-accent-light: #3b82f6;
    --color-accent-dark: #1d4ed8;

    /* Strategic Color Accents */
    --color-teal: #0d9488;
    --color-teal-light: #14b8a6;
    --color-teal-bg: #f0fdfa;

    --color-amber: #d97706;
    --color-amber-light: #f59e0b;
    --color-amber-bg: #fffbeb;

    --color-coral: #dc2626;
    --color-coral-light: #ef4444;
    --color-coral-bg: #fef2f2;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #2563eb, #7c3aed);
    --gradient-teal: linear-gradient(135deg, #0d9488, #14b8a6);
    --gradient-amber: linear-gradient(135deg, #d97706, #f59e0b);

    /* Borders */
    --color-border: #e5e5e5;
    --color-border-dark: #d4d4d4;
    --color-shadow: rgba(0, 0, 0, 0.1);
    --color-shadow-strong: rgba(0, 0, 0, 0.2);

    /* Typography */
    --font-body: 'Georgia', 'Palatino', 'Times New Roman', serif;
    --font-heading: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', 'Helvetica Neue', sans-serif;
    --font-mono: 'Fira Code', 'JetBrains Mono', 'Consolas', monospace;

    /* Font Sizes - Increased by 20% */
    --text-xs: 1.05rem;      /* 0.875 × 1.2 */
    --text-sm: 1.2rem;       /* 1 × 1.2 */
    --text-base: 1.35rem;    /* 1.125 × 1.2 */
    --text-lg: 1.5rem;       /* 1.25 × 1.2 */
    --text-xl: 1.8rem;       /* 1.5 × 1.2 */
    --text-2xl: 2.25rem;     /* 1.875 × 1.2 */
    --text-3xl: 2.7rem;      /* 2.25 × 1.2 */
    --text-4xl: 3.6rem;      /* 3 × 1.2 */

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;

    /* Layout - Unified Content Column */
    --width-text: 1100px;         /* Body paragraphs */
    --width-image: 1100px;        /* Images - SAME as text for unified column */
    --width-cards: 1100px;        /* Card grids - SAME as text */
    --width-full: 100%;           /* Full-width sections (hero/headers only) */
    --sidebar-width: 280px;

    /* Line Heights */
    --line-height-tight: 1.3;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.7;
    --line-height-loose: 1.8;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-text: #e5e5e5;
    --color-text-light: #a3a3a3;
    --color-background: #1a1a1a;
    --color-surface: #262626;
    --color-surface-alt: #2d2d2d;
    --color-accent: #3b82f6;
    --color-accent-light: #60a5fa;
    --color-accent-dark: #2563eb;
    --color-border: #404040;
    --color-border-dark: #525252;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-shadow-strong: rgba(0, 0, 0, 0.5);

    /* Strategic colors for dark mode */
    --color-teal: #14b8a6;
    --color-teal-light: #2dd4bf;
    --color-teal-bg: #042f2e;

    --color-amber: #f59e0b;
    --color-amber-light: #fbbf24;
    --color-amber-bg: #422006;

    --color-coral: #ef4444;
    --color-coral-light: #f87171;
    --color-coral-bg: #450a0a;
}

/* ===================================
   Reset & Base Styles
   =================================== */

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    font-size: 22px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-background);
    transition: background-color var(--transition-normal), color var(--transition-normal);
    overflow-x: hidden;
}

/* ===================================
   Typography
   =================================== */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: var(--line-height-tight);
    color: var(--color-text);
    margin-bottom: var(--space-md);
}

h1 {
    font-size: 3.6rem;
    margin-bottom: var(--space-lg);
}

h2 {
    font-size: 2.7rem;
    margin-top: var(--space-2xl);
    margin-bottom: var(--space-lg);
}

h3 {
    font-size: 2.25rem;
    margin-top: var(--space-xl);
    margin-bottom: var(--space-md);
}

p {
    font-size: 22px;
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    position: relative;
    transition: color var(--transition-fast);
}

a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -2px;
    left: 0;
    background: var(--color-accent);
    transition: width var(--transition-normal);
}

a:hover::after {
    width: 100%;
}

a:hover {
    color: var(--color-accent-light);
}

a:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

strong {
    font-weight: 700;
    color: var(--color-text);
}

em {
    font-style: italic;
}

/* Lists */
ul, ol {
    margin-bottom: var(--space-md);
    padding-left: var(--space-xl);
}

li {
    margin-bottom: var(--space-xs);
    line-height: var(--line-height-relaxed);
}

/* ===================================
   Progress Bar
   =================================== */

.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: var(--gradient-primary);
    width: 0%;
    z-index: 9999;
    transition: width var(--transition-fast);
}

/* ===================================
   Current Part Indicator (Sticky)
   =================================== */

.current-part-indicator {
    position: fixed;
    top: 80px;
    right: var(--space-lg);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xs) var(--space-md);
    font-family: var(--font-heading);
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-accent);
    box-shadow: 0 2px 8px var(--color-shadow);
    z-index: 100;
    opacity: 0;
    transform: translateY(-10px);
    transition: all var(--transition-normal);
}

.current-part-indicator.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===================================
   Dark Mode Toggle
   =================================== */

.dark-mode-toggle {
    position: fixed;
    top: var(--space-md);
    right: var(--space-md);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-sm);
    cursor: pointer;
    z-index: 1000;
    box-shadow: 0 2px 8px var(--color-shadow);
    transition: all var(--transition-normal);
    font-size: var(--text-lg);
}

.dark-mode-toggle:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px var(--color-shadow-strong);
}

.dark-mode-toggle:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

[data-theme="light"] .icon-moon {
    display: none;
}

[data-theme="dark"] .icon-sun {
    display: none;
}

/* ===================================
   Sidebar Navigation - HIDDEN
   =================================== */

.sidebar {
    display: none;
}

.sidebar-header {
    display: none;
}

.sidebar-toggle {
    display: none;
}

/* Table of Contents */
.toc {
    display: none;
}

.toc a {
    display: none;
}

/* ===================================
   Main Content
   =================================== */

.content {
    margin-left: 0;
    padding: 0;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
}

article {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Variable Width Content Containers */
.content-text,
.content-section > p,
.content-section > ul,
.content-section > ol,
.content-section > h3,
.content-section > .challenge,
.content-section > .key-insight {
    max-width: var(--width-text);
    width: 90%;
    padding: 0 var(--space-lg);
    align-self: center;
}

.content-image,
.image-container {
    max-width: var(--width-image);
    width: 90%;
    margin: var(--space-2xl) auto;
    align-self: center;
}

.content-cards,
.options-grid,
.answers-grid,
.epilogue-questions-grid,
.proceed-grid {
    max-width: var(--width-cards);
    width: 90%;
    align-self: center;
}

.full-width-section {
    width: 100%;
    padding: var(--space-3xl) 5%;
    align-self: stretch;
}

/* Opening scene and header use unified column width */
.opening-scene,
.article-header {
    max-width: var(--width-text);
    width: 90%;
    padding: var(--space-2xl) var(--space-lg);
    align-self: center;
}

/* ===================================
   Article Header
   =================================== */

.article-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
    padding-bottom: var(--space-xl);
    border-bottom: 2px solid var(--color-border);
}

.main-title {
    font-size: clamp(2rem, 5vw, var(--text-4xl));
    margin-bottom: var(--space-md);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: var(--text-xl);
    color: var(--color-text-light);
    font-family: var(--font-heading);
    font-weight: 400;
    margin-bottom: var(--space-lg);
}

.reading-info {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    font-size: var(--text-sm);
    color: var(--color-text-light);
    font-family: var(--font-heading);
}

/* ===================================
   Opening Scene & Dialogue
   =================================== */

.opening-scene {
    background: linear-gradient(135deg, var(--color-surface-alt), var(--color-surface));
    padding: var(--space-2xl);
    border-radius: var(--radius-xl);
    margin-bottom: var(--space-2xl);
    position: relative;
}

.opening-scene h2 {
    margin-top: 0;
}

.dialogue {
    background: var(--color-surface);
    border-left: 4px solid var(--color-accent);
    padding: var(--space-xl);
    margin: var(--space-xl) 0;
    border-radius: var(--radius-md);
    box-shadow: 0 4px 12px var(--color-shadow);
}

.dialogue p {
    margin-bottom: var(--space-md);
    font-size: var(--text-lg);
}

.dialogue p:last-child {
    margin-bottom: 0;
}

.dialogue-teacher {
    color: var(--color-accent);
    font-weight: 500;
}

.dialogue-student {
    color: var(--color-teal);
    font-weight: 500;
}

.dialogue-response {
    font-weight: 600;
}

.scene-conclusion {
    font-size: var(--text-lg);
    color: var(--color-text-light);
    line-height: var(--line-height-loose);
    margin-top: var(--space-xl);
}

/* ===================================
   Section Dividers
   =================================== */

.section-divider {
    border: none;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--color-border), transparent);
    margin: var(--space-3xl) 0;
    width: 100%;
    align-self: stretch;
}

/* ===================================
   Content Sections
   =================================== */

.content-section {
    width: 100%;
    margin-bottom: var(--space-3xl);
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s ease forwards;
    display: flex;
    flex-direction: column;
    align-items: center;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section-title {
    position: relative;
    padding-bottom: var(--space-md);
    border-bottom: 2px solid var(--color-border);
    max-width: var(--width-text);
    width: 90%;
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
    align-self: center;
}

.part-number {
    font-weight: 700;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===================================
   Special Text Elements
   =================================== */

.challenge {
    background: var(--color-surface-alt);
    border-left: 4px solid var(--color-accent);
    padding: var(--space-md) var(--space-lg);
    margin: var(--space-lg) 0;
    font-size: var(--text-lg);
    border-radius: var(--radius-md);
}

.key-insight {
    font-weight: 600;
    color: var(--color-accent);
    font-size: var(--text-lg);
    margin: var(--space-lg) 0;
}

/* ===================================
   Insight Boxes (Color Coded)
   =================================== */

.insight-box {
    padding: var(--space-xl);
    margin: var(--space-xl) 0;
    border-radius: var(--radius-lg);
    border-left: 6px solid;
    font-size: var(--text-lg);
    line-height: var(--line-height-loose);
    box-shadow: 0 4px 12px var(--color-shadow);
    transition: transform var(--transition-normal);
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
}

.insight-box:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px var(--color-shadow-strong);
}

.insight-box.teal-insight {
    background: var(--color-teal-bg);
    border-color: var(--color-teal);
}

.insight-box.amber-insight {
    background: var(--color-amber-bg);
    border-color: var(--color-amber);
}

.insight-box.coral-insight {
    background: var(--color-coral-bg);
    border-color: var(--color-coral);
}

.insight-box.large-insight {
    font-size: var(--text-2xl);
    text-align: center;
    padding: var(--space-2xl);
}

.insight-box p {
    margin: 0;
}

.insight-box ul {
    margin-bottom: 0;
    margin-top: var(--space-md);
}

/* ===================================
   Pull Quotes
   =================================== */

.pull-quote-large {
    font-size: var(--text-2xl);
    font-family: var(--font-body);
    font-weight: 600;
    font-style: italic;
    color: var(--color-accent);
    text-align: center;
    margin: var(--space-2xl) 0;
    padding: var(--space-2xl);
    line-height: var(--line-height-normal);
    position: relative;
    border-top: 3px solid var(--color-border);
    border-bottom: 3px solid var(--color-border);
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
}

.pull-quote-large.sacred-quote {
    font-size: var(--text-3xl);
    background: linear-gradient(135deg, var(--color-surface-alt), transparent);
    border-radius: var(--radius-lg);
    border: 2px solid var(--color-border);
}

.pull-quote-large.final-quote {
    font-size: clamp(1.5rem, 4vw, 2.5rem);
    color: var(--color-teal);
}

.pull-quote-large.final-insight {
    background: var(--color-teal-bg);
    color: var(--color-teal);
    border-color: var(--color-teal);
}

.pull-quote-large p {
    margin: 0;
}

/* ===================================
   Image Containers
   =================================== */

.image-container {
    width: 100%;
    margin: var(--space-2xl) 0;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: 0 4px 16px var(--color-shadow);
}

.image-container.large-image {
    margin: var(--space-3xl) 0;
}

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

.fade-in-image {
    opacity: 0;
    animation: fadeIn 0.8s ease forwards;
}

@keyframes fadeIn {
    to {
        opacity: 1;
    }
}

.image-caption {
    font-size: var(--text-sm);
    color: var(--color-text-light);
    font-style: italic;
    margin-top: var(--space-md);
    line-height: var(--line-height-relaxed);
    max-width: var(--width-image);
    width: 90%;
    padding: 0 var(--space-lg);
    align-self: center;
}

/* ===================================
   Technical Details (Expandable)
   =================================== */

.technical-detail {
    background: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    margin: var(--space-lg) 0;
    overflow: hidden;
    transition: box-shadow var(--transition-normal);
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
}

.technical-detail:hover {
    box-shadow: 0 4px 12px var(--color-shadow);
}

.technical-detail summary {
    padding: var(--space-md) var(--space-lg);
    cursor: pointer;
    user-select: none;
    list-style: none;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    transition: background var(--transition-fast);
    font-family: var(--font-heading);
}

.technical-detail summary::-webkit-details-marker {
    display: none;
}

.technical-detail summary::before {
    content: '+';
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.5em;
    height: 1.5em;
    border-radius: 50%;
    background: var(--color-accent);
    color: white;
    font-weight: 700;
    transition: transform var(--transition-fast);
}

.technical-detail[open] summary::before {
    content: '−';
    transform: rotate(180deg);
}

.technical-detail summary:hover {
    background: var(--color-surface);
}

.technical-detail[open] summary {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}

.detail-content {
    padding: var(--space-lg);
    animation: slideDown 0.3s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===================================
   Math Rendering
   =================================== */

.katex-formula {
    font-family: var(--font-mono);
    background: var(--color-surface-alt);
    padding: 0.2em 0.4em;
    border-radius: var(--radius-sm);
    font-size: 0.95em;
}

.math-display {
    background: var(--color-surface-alt);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    margin: var(--space-lg) 0;
    overflow-x: auto;
    text-align: center;
}

.math-display .katex-formula {
    background: transparent;
    padding: 0;
    font-size: 1.2em;
}

/* ===================================
   Card Layouts
   =================================== */

/* Options Grid (Part VIII) */
.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-lg);
    margin: var(--space-2xl) 0;
}

.option-card {
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    transition: all var(--transition-normal);
}

.option-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px var(--color-shadow-strong);
    border-color: var(--color-accent);
}

.option-card.highlight-card {
    background: var(--color-teal-bg);
    border-color: var(--color-teal);
    border-width: 3px;
}

.option-card h4 {
    color: var(--color-accent);
    margin-bottom: var(--space-sm);
    font-size: var(--text-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.option-card .option-title {
    font-weight: 700;
    font-size: var(--text-lg);
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.option-card .option-response {
    color: var(--color-text-light);
    font-size: var(--text-sm);
    margin: 0;
}

/* Answers Grid (Part X) */
.answers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-md);
    margin: var(--space-2xl) 0;
}

.answer-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    transition: all var(--transition-normal);
}

.answer-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--color-shadow);
}

.answer-card.highlight-card {
    background: var(--color-amber-bg);
    border-color: var(--color-amber);
    border-width: 2px;
}

.answer-card .answer-number {
    font-family: var(--font-heading);
    font-size: var(--text-xs);
    font-weight: 700;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-xs);
}

.answer-card .answer-title {
    font-weight: 600;
    font-size: var(--text-base);
    margin-bottom: var(--space-sm);
    color: var(--color-text);
}

.answer-card .answer-assessment {
    color: var(--color-text-light);
    font-size: var(--text-sm);
    margin: 0;
}

/* Epilogue Questions Grid */
.epilogue-questions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-lg);
    margin: var(--space-2xl) 0;
}

.question-card {
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    position: relative;
    transition: all var(--transition-normal);
    min-height: 150px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.question-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px var(--color-shadow-strong);
    border-color: var(--color-accent);
}

.question-card .question-number {
    position: absolute;
    top: var(--space-md);
    left: var(--space-md);
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--color-accent);
    opacity: 0.2;
    font-family: var(--font-heading);
}

.question-card p {
    font-size: var(--text-lg);
    line-height: var(--line-height-relaxed);
    margin: 0;
    padding-left: var(--space-2xl);
}

/* Proceed Grid (Part XI) */
.proceed-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-xl);
    margin: var(--space-2xl) 0;
}

.proceed-card {
    background: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    transition: all var(--transition-normal);
}

.proceed-card:hover {
    background: var(--color-surface);
    box-shadow: 0 4px 12px var(--color-shadow);
}

.proceed-card h4 {
    color: var(--color-accent);
    margin-bottom: var(--space-md);
    font-size: var(--text-xl);
}

.proceed-card ul {
    margin: 0;
    padding-left: var(--space-lg);
}

.proceed-card li {
    margin-bottom: var(--space-sm);
}

/* ===================================
   Inversion Comparison (Part IX)
   =================================== */

.inversion-comparison {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xl);
    margin: var(--space-2xl) 0;
    padding: var(--space-2xl);
    background: var(--color-surface-alt);
    border-radius: var(--radius-xl);
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
}

.old-view,
.new-view {
    flex: 1;
    text-align: center;
    padding: var(--space-lg);
    border-radius: var(--radius-md);
}

.old-view {
    background: var(--color-surface);
    border: 2px solid var(--color-border);
}

.new-view {
    background: var(--color-teal-bg);
    border: 2px solid var(--color-teal);
}

.inversion-comparison .label {
    font-family: var(--font-heading);
    font-size: var(--text-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-light);
    margin-bottom: var(--space-sm);
}

.inversion-comparison .quote {
    font-size: var(--text-lg);
    font-weight: 600;
    font-style: italic;
    color: var(--color-text);
    margin: 0;
}

.inversion-comparison .arrow {
    font-size: var(--text-3xl);
    color: var(--color-accent);
    font-weight: 700;
}

/* ===================================
   Meta Section
   =================================== */

.meta-section {
    background: var(--color-surface-alt);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    margin: var(--space-2xl) 0;
    border-left: 4px solid var(--color-accent);
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
}

.meta-text {
    font-style: italic;
    color: var(--color-text-light);
    margin-bottom: var(--space-md);
}

.meta-text:last-child {
    margin-bottom: 0;
}

/* ===================================
   Footer
   =================================== */

.article-footer {
    margin-top: var(--space-3xl);
    padding-top: var(--space-xl);
    border-top: 2px solid var(--color-border);
    text-align: center;
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
}

.creation-date {
    margin-bottom: var(--space-lg);
    color: var(--color-text-light);
}

/* ===================================
   Responsive Design
   =================================== */

/* Wide Monitors */
@media (min-width: 1600px) {
    :root {
        --width-text: 1200px;
        --width-image: 1200px;        /* SAME as text for unified column */
        --width-cards: 1200px;        /* SAME as text */
    }
}

/* Tablet */
@media (max-width: 1024px) {
    :root {
        --text-base: 1.0625rem;
        --width-text: 900px;
        --width-image: 90vw;
        --width-cards: 90vw;
    }

    .content {
        margin-left: 0;
        padding: 0;
    }

    .dark-mode-toggle {
        top: var(--space-md);
        right: var(--space-md);
    }

    .current-part-indicator {
        top: 70px;
        right: var(--space-md);
    }

    .inversion-comparison {
        flex-direction: column;
    }

    .inversion-comparison .arrow {
        transform: rotate(90deg);
    }

    .options-grid,
    .answers-grid,
    .epilogue-questions-grid {
        grid-template-columns: 1fr;
    }
}

/* Mobile */
@media (max-width: 640px) {
    :root {
        --text-base: 1rem;
        --text-xl: 1.25rem;
        --text-2xl: 1.5rem;
        --text-3xl: 1.875rem;
        --text-4xl: 2.25rem;
        --space-xl: 2rem;
        --space-2xl: 3rem;
        --space-3xl: 4rem;
        --width-text: 95vw;
        --width-image: 95vw;
        --width-cards: 95vw;
    }

    body, p {
        font-size: 19px;
    }

    h1 {
        font-size: 2.4rem;
    }

    h2 {
        font-size: 2.1rem;
    }

    h3 {
        font-size: 1.5rem;
    }

    .content {
        padding: 0;
    }

    .content-section > p,
    .content-section > ul,
    .content-section > ol,
    .content-section > h3 {
        padding: 0 var(--space-sm);
    }

    .article-header {
        margin-bottom: var(--space-2xl);
    }

    .reading-info {
        flex-direction: column;
        gap: var(--space-xs);
    }

    .pull-quote-large {
        font-size: var(--text-xl);
        padding: var(--space-lg);
    }

    .dialogue {
        padding: var(--space-lg);
    }

    .opening-scene {
        padding: var(--space-lg);
    }

    .current-part-indicator {
        top: 60px;
        right: var(--space-sm);
        font-size: var(--text-xs);
        padding: 0.4rem 0.8rem;
    }

    .proceed-grid {
        grid-template-columns: 1fr;
    }

    .question-card p {
        font-size: var(--text-base);
    }
}

/* ===================================
   Print Styles
   =================================== */

@media print {
    @page {
        margin: 2cm;
    }

    body {
        background: white;
        color: black;
        font-size: 12pt;
        line-height: 1.6;
    }

    .sidebar,
    .dark-mode-toggle,
    .progress-bar,
    .current-part-indicator,
    .sidebar-toggle {
        display: none !important;
    }

    .content {
        margin-left: 0;
        padding: 0;
        max-width: 100%;
    }

    article {
        max-width: 100%;
    }

    h1, h2, h3 {
        page-break-after: avoid;
        break-after: avoid;
    }

    .content-section {
        page-break-inside: avoid;
        break-inside: avoid;
    }

    .section-divider {
        page-break-before: always;
        break-before: always;
    }

    a {
        color: black;
        text-decoration: underline;
    }

    a::after {
        display: none;
    }

    a[href^="http"]::after {
        content: " (" attr(href) ")";
        font-size: 0.8em;
        font-style: italic;
    }

    .main-title,
    .gradient-text {
        background: none !important;
        -webkit-text-fill-color: initial !important;
        color: black !important;
    }

    .image-container {
        box-shadow: none;
    }

    .technical-detail summary::before {
        display: none;
    }

    .technical-detail .detail-content {
        display: block;
    }

    .insight-box,
    .option-card,
    .answer-card,
    .question-card {
        box-shadow: none;
        page-break-inside: avoid;
    }
}

/* ===================================
   Accessibility Enhancements
   =================================== */

/* Focus visible for keyboard navigation */
:focus-visible {
    outline: 3px solid var(--color-accent);
    outline-offset: 3px;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000;
        --color-text: #000;
    }

    [data-theme="dark"] {
        --color-border: #fff;
        --color-text: #fff;
    }
}

/* ===================================
   Smooth Scroll Animation
   =================================== */

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ===================================
   Utilities
   =================================== */

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

.mb-0 {
    margin-bottom: 0;
}

.mt-0 {
    margin-top: 0;
}

/* Selection styling */
::selection {
    background: var(--color-accent-light);
    color: white;
}

::-moz-selection {
    background: var(--color-accent-light);
    color: white;
}

/* ===================================
   Interactive Components
   =================================== */

.interactive-container {
    background: var(--color-surface-alt);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    margin: var(--space-3xl) 0;
    max-width: var(--width-text);
    width: 90%;
    align-self: center;
    box-shadow: 0 4px 20px var(--color-shadow);
}

.interactive-title {
    font-family: var(--font-heading);
    font-size: var(--text-xl);
    color: var(--color-accent);
    margin: 0 0 var(--space-lg) 0;
    text-align: center;
}

#polygon-canvas {
    display: block;
    width: 100%;
    max-width: 800px;
    height: auto;
    aspect-ratio: 1;
    margin: 0 auto var(--space-xl);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: inset 0 2px 8px var(--color-shadow);
    cursor: crosshair;
}

.interactive-controls {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.control-group label {
    font-size: var(--text-base);
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.control-group input[type="range"] {
    width: 100%;
    height: 8px;
    border-radius: var(--radius-sm);
    background: var(--color-border);
    outline: none;
    transition: background var(--transition-fast);
    cursor: pointer;
}

.control-group input[type="range"]:hover {
    background: var(--color-border-dark);
}

.control-group input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--color-accent);
    cursor: pointer;
    box-shadow: 0 2px 6px var(--color-shadow);
    transition: transform var(--transition-fast);
}

.control-group input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.control-group input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--color-accent);
    cursor: pointer;
    box-shadow: 0 2px 6px var(--color-shadow);
    border: none;
    transition: transform var(--transition-fast);
}

.control-group input[type="range"]::-moz-range-thumb:hover {
    transform: scale(1.2);
}

.slider-marks {
    display: flex;
    justify-content: space-between;
    font-size: var(--text-xs);
    color: var(--color-text-light);
    margin-top: -4px;
}

.polygon-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    padding: var(--space-lg);
    background: var(--color-surface);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-accent);
}

.stat-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.stat-label {
    font-size: var(--text-sm);
    color: var(--color-text-light);
    font-weight: 600;
}

.stat-value {
    font-size: var(--text-lg);
    font-family: var(--font-mono);
    color: var(--color-accent);
    font-weight: 700;
}

.interactive-hint {
    font-size: var(--text-sm);
    color: var(--color-text-light);
    text-align: center;
    margin: var(--space-md) 0 0 0;
    font-style: italic;
}

/* Mobile responsive */
@media (max-width: 640px) {
    .interactive-container {
        padding: var(--space-lg);
    }

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

    #polygon-canvas {
        max-width: 100%;
    }
}

/* Scrollbar styling (Webkit) */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--color-surface-alt);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border-dark);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-accent);
}