/* ==========================================================================
   STYLE.CSS - DESIGN SYSTEM & UI LAYOUT
   Project: L'Observatoire des Annuaires (Digital Literacy & Telecom Privacy)
   Aesthetic: Institutional, Trustworthy, High Credibility (Navy, Whites, Slates)
   ========================================================================== */

/* Import Google Font (Inter) for modern, clean typography */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* --- 1. DESIGN TOKENS (GLOBAL VARIABLES) --- */
:root {
    /* Color Palette */
    --primary: #0f172a;        /* Deep Navy blue for headers, solid branding */
    --primary-light: #1e293b;  /* Slate Navy for secondary headers and text */
    --primary-bg: #090d16;     /* Dark navy for hero banner */
    --accent: #0284c7;         /* Clear Sky Blue for action cues & indicators */
    --accent-hover: #0369a1;   /* Deeper blue for hover states */
    --accent-light: #e0f2fe;   /* Soft blue tint for alerts and badges */
    
    --bg-base: #f8fafc;        /* Off-white/slate tint for page background */
    --bg-surface: #ffffff;     /* Pure white for containers, cards, content */
    --bg-surface-alt: #f1f5f9; /* Light gray-blue for sidebar widgets, table heads */
    
    --text-main: #334155;      /* Slate charcoal for high legibility body text */
    --text-muted: #64748b;     /* Slate gray for secondary details, timestamps */
    --text-heading: #0f172a;   /* Crisp black-navy for all headings */
    --text-on-primary: #ffffff;/* White text on dark navy components */
    
    --border-color: #cbd5e1;   /* Light gray border to structure components */
    --border-light: #e2e8f0;   /* Very light border for cards */
    --border-focus: #38bdf8;   /* Bright focus ring color */
    
    --success: #15803d;        /* Trust green for safe badges */
    --success-light: #dcfce7;
    --warning: #b45309;        /* Warm amber for warnings and alert boxes */
    --warning-light: #fef3c7;
    
    /* Layout & Spacing */
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
    --max-width: 1200px;
    --header-height: 70px;
    
    /* Borders & Shadow effects */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.03);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.05), 0 4px 6px -2px rgba(15, 23, 42, 0.02);
    
    /* Animations */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- 2. BASE RESET & GENERAL STYLES --- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-base);
    color: var(--text-main);
    line-height: 1.65;
    padding-top: var(--header-height); /* Prevent content hiding behind sticky nav */
}

/* Typography elements */
h1, h2, h3, h4, h5, h6 {
    color: var(--text-heading);
    font-weight: 700;
    line-height: 1.25;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.25rem;
    letter-spacing: -0.025em;
}

h2 {
    font-size: 1.75rem;
    margin-top: 2rem;
    border-bottom: 2px solid var(--border-light);
    padding-bottom: 0.5rem;
}

h3 {
    font-size: 1.35rem;
    margin-top: 1.5rem;
}

p {
    margin-bottom: 1.25rem;
}

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

a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
    border-radius: var(--radius-md);
}

ul, ol {
    margin-bottom: 1.25rem;
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0.5rem;
}

/* Utility Containers */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin-left: auto;
    margin-right: auto;
    padding-left: 1.5rem;
    padding-right: 1.5rem;
}

/* --- 3. STICKY NAVIGATION HEADER --- */
header {
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-light);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none !important;
}

.logo-icon {
    font-size: 1.75rem;
    color: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--accent-light);
    width: 42px;
    height: 42px;
    border-radius: var(--radius-md);
    font-weight: 800;
    border: 1px solid rgba(2, 132, 199, 0.2);
}

.logo-text {
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--primary);
    line-height: 1.1;
}

.logo-sub {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* Main Navigation Menu */
.nav-menu {
    display: flex;
    gap: 1.5rem;
    list-style: none;
}

.nav-link {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--primary-light);
    padding: 0.5rem 0;
    position: relative;
}

.nav-link:hover, .nav-link.active {
    color: var(--accent);
    text-decoration: none;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--accent);
    transform: scaleX(0);
    transition: transform var(--transition-fast);
}

.nav-link:hover::after, .nav-link.active::after {
    transform: scaleX(1);
}

/* Mobile Menu Button */
.btn-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    flex-direction: column;
    gap: 5px;
    width: 32px;
}

.btn-menu-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--primary);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

/* Mobile Navigation Dropdown */
.mobile-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--bg-surface);
    border-bottom: 2px solid var(--border-color);
    padding: 1.5rem;
    flex-direction: column;
    gap: 1rem;
    box-shadow: var(--shadow-lg);
    z-index: 999;
}

.mobile-nav-link {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-heading);
    padding: 0.5rem 0;
}

/* --- 4. HERO SECTION (INSTITUTIONAL HEADER) --- */
.hero {
    background: radial-gradient(ellipse at top, var(--primary-light), var(--primary-bg));
    color: var(--text-on-primary);
    padding: 5rem 0 5rem 0;
    text-align: center;
    border-bottom: 4px solid var(--accent);
}

.hero h1 {
    color: #ffffff;
    font-size: 2.75rem;
    max-width: 850px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.2;
}

.hero p {
    font-size: 1.15rem;
    color: #cbd5e1;
    max-width: 650px;
    margin: 1.5rem auto 2.5rem;
    font-weight: 300;
}

.hero-ctas {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.75rem;
    font-weight: 600;
    font-size: 0.95rem;
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: var(--accent);
    color: #ffffff;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    color: #ffffff;
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(2, 132, 199, 0.35);
}

.btn-secondary {
    background-color: transparent;
    color: #ffffff;
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.08);
    border-color: #ffffff;
    color: #ffffff;
    text-decoration: none;
    transform: translateY(-2px);
}

/* --- 5. BREADCRUMBS SYSTEM --- */
.breadcrumbs {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.breadcrumbs a {
    color: var(--text-muted);
    font-weight: 500;
}

.breadcrumbs a:hover {
    color: var(--accent);
    text-decoration: none;
}

.breadcrumbs span::after {
    content: '/';
    margin-left: 0.5rem;
    color: var(--border-color);
}

.breadcrumbs .current {
    color: var(--text-main);
    font-weight: 600;
}

/* --- 6. CORE LAYOUT GRID (HOMEPAGE AND RESOURCES) --- */
.main-layout {
    display: grid;
    grid-template-columns: 240px 1fr 280px;
    gap: 2rem;
    padding-top: 3rem;
    padding-bottom: 5rem;
}

/* Layout variation for Home: Single main block or asymmetric columns */
.home-layout {
    display: flex;
    flex-direction: column;
    gap: 4rem;
    padding-top: 4rem;
    padding-bottom: 6rem;
}

/* Hub Directory Grid (Pillar Links) */
.hub-section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.hub-section-subtitle {
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hub-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.75rem;
}

.hub-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.hub-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background-color: var(--border-light);
    transition: background-color var(--transition-fast);
}

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

.hub-card:hover::before {
    background-color: var(--accent);
}

.card-num {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
    display: inline-block;
}

.hub-card h3 {
    margin-top: 0;
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    line-height: 1.35;
}

.hub-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.hub-card-link {
    font-weight: 600;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent);
}

.hub-card-link:hover {
    text-decoration: none;
}

.hub-card-link::after {
    content: '→';
    transition: transform var(--transition-fast);
}

.hub-card:hover .hub-card-link::after {
    transform: translateX(4px);
}

/* --- 7. ARTICLE CONTENT AREA & SIDEBARS --- */
.content-area {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    box-shadow: var(--shadow-sm);
    min-width: 0; /* Prevents overflow issues in flex items */
}

/* Left Sidebar (TOC) */
.sidebar-left {
    position: sticky;
    top: calc(var(--header-height) + 1.5rem);
    height: fit-content;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* Right Sidebar (EEAT / Related) */
.sidebar-right {
    position: sticky;
    top: calc(var(--header-height) + 1.5rem);
    height: fit-content;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* General Sidebar Boxes */
.sidebar-box {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    box-shadow: var(--shadow-sm);
}

.sidebar-box h4 {
    font-size: 0.95rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--primary-light);
    border-bottom: 2px solid var(--bg-surface-alt);
    padding-bottom: 0.5rem;
    margin-bottom: 0.75rem;
}

/* Menu links in Sidebars */
.sidebar-menu {
    list-style: none;
    padding-left: 0;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.sidebar-menu-link {
    display: block;
    font-size: 0.85rem;
    color: var(--text-main);
    padding: 0.35rem 0.5rem;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.sidebar-menu-link:hover, .sidebar-menu-link.active {
    background-color: var(--bg-surface-alt);
    color: var(--accent);
    text-decoration: none;
    padding-left: 0.75rem;
}

/* Table of Contents (TOC) list */
.toc-list {
    list-style: none;
    padding-left: 0;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.toc-link {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-decoration: none;
    display: inline-block;
    padding: 0.15rem 0;
    transition: color var(--transition-fast);
}

.toc-link:hover {
    color: var(--accent);
    text-decoration: none;
}

.toc-depth-3 {
    padding-left: 1rem;
    font-size: 0.8rem;
}

/* EEAT Badge Style */
.eeat-badge {
    background: linear-gradient(135deg, var(--primary-light), var(--primary-bg));
    color: #ffffff;
    border-radius: var(--radius-md);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--accent);
}

.eeat-badge-title {
    font-weight: 700;
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.eeat-badge-desc {
    font-size: 0.8rem;
    line-height: 1.5;
    color: #94a3b8;
    margin-bottom: 0.75rem;
}

.eeat-badge-meta {
    font-size: 0.7rem;
    color: var(--accent-light);
    font-weight: 600;
    text-transform: uppercase;
}

/* --- 8. ARTICLE FORMATTING & COMPONENTS --- */
.article-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    border-bottom: 1px solid var(--border-light);
    padding-bottom: 1rem;
}

.article-meta span {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.article-body {
    font-size: 1.05rem;
    color: var(--text-main);
    line-height: 1.75;
}

/* Safe Alerts / Warnings (GDPR, Telecom Scams) */
.alert-box {
    padding: 1.25rem;
    border-radius: var(--radius-md);
    margin: 1.5rem 0;
    font-size: 0.95rem;
    line-height: 1.6;
    border-left: 4px solid;
}

.alert-box-warning {
    background-color: var(--warning-light);
    color: var(--warning);
    border-left-color: var(--warning);
}

.alert-box-info {
    background-color: var(--accent-light);
    color: var(--accent-hover);
    border-left-color: var(--accent);
}

.alert-box-success {
    background-color: var(--success-light);
    color: var(--success);
    border-left-color: var(--success);
}

.alert-box-title {
    font-weight: 700;
    margin-bottom: 0.35rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Custom Table Style for Directory references */
.data-table-container {
    overflow-x: auto;
    margin: 2rem 0;
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    text-align: left;
}

.data-table th, .data-table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-light);
}

.data-table th {
    background-color: var(--bg-surface-alt);
    font-weight: 600;
    color: var(--text-heading);
}

.data-table tr:last-child td {
    border-bottom: none;
}

.data-table tbody tr:hover {
    background-color: rgba(241, 245, 249, 0.5);
}

/* --- 9. INTERACTIVE ELEMENTS (FAQ & INTERACTIVE COMPONENT) --- */
/* FAQ Section styling */
.faq-section {
    margin-top: 3.5rem;
    border-top: 2px solid var(--border-light);
    padding-top: 2.5rem;
}

.faq-title {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.faq-item {
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    background-color: var(--bg-surface);
    overflow: hidden;
    transition: border-color var(--transition-fast);
}

.faq-item:hover {
    border-color: var(--border-color);
}

.faq-question {
    width: 100%;
    text-align: left;
    background: none;
    border: none;
    padding: 1.25rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-heading);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    transition: background-color var(--transition-fast);
}

.faq-question::after {
    content: '+';
    font-size: 1.25rem;
    color: var(--text-muted);
    transition: transform var(--transition-fast);
}

.faq-item.active .faq-question {
    background-color: var(--bg-surface-alt);
}

.faq-item.active .faq-question::after {
    content: '−';
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal) ease-out;
}

.faq-answer-inner {
    padding: 1.25rem;
    border-top: 1px solid var(--border-light);
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-main);
}

/* Interactive Simulator Widget */
.widget-container {
    background-color: var(--bg-surface-alt);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin: 2rem 0;
}

.widget-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-heading);
    margin-bottom: 0.5rem;
}

.widget-desc {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

.widget-search-box {
    display: flex;
    gap: 0.75rem;
}

.widget-input {
    flex-grow: 1;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.95rem;
}

.widget-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.15);
}

.widget-button {
    background-color: var(--accent);
    color: #ffffff;
    border: none;
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.widget-button:hover {
    background-color: var(--accent-hover);
}

.widget-log {
    margin-top: 1.25rem;
    padding: 1rem;
    background-color: #0f172a;
    color: #38bdf8;
    border-radius: var(--radius-md);
    font-family: monospace;
    font-size: 0.8rem;
    min-height: 80px;
    max-height: 200px;
    overflow-y: auto;
    white-space: pre-wrap;
    line-height: 1.5;
}

/* --- 10. INSTITUTIONAL FOOTER --- */
footer {
    background-color: var(--primary);
    color: #cbd5e1;
    padding: 4rem 0 2rem;
    font-size: 0.85rem;
    border-top: 4px solid var(--accent);
}

footer h4 {
    color: #ffffff;
    font-size: 1rem;
    margin-bottom: 1.25rem;
    font-weight: 600;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-logo {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-logo h4 {
    font-size: 1.15rem;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 0.5rem;
}

.footer-menu {
    list-style: none;
    padding-left: 0;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
}

.footer-menu a {
    color: #94a3b8;
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-menu a:hover {
    color: #ffffff;
}

.footer-disclaimer {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    margin-bottom: 2rem;
    color: #64748b;
    line-height: 1.5;
    font-size: 0.75rem;
    text-align: justify;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 1.5rem;
    color: #64748b;
    flex-wrap: wrap;
    gap: 1rem;
}

/* --- 12. CONTACT FORM STYLES --- */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 3rem;
    align-items: start;
    margin-top: 2rem;
}

.contact-info {
    font-size: 0.95rem;
    line-height: 1.65;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    background-color: var(--bg-surface);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-heading);
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.9rem;
    transition: all var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.15);
}

textarea.form-control {
    min-height: 120px;
    resize: vertical;
}

/* --- 11. RESPONSIVE DESIGN & MEDIA QUERIES --- */

/* Medium Devices (Tablets, max-width: 1024px) */
@media (max-width: 1024px) {
    .main-layout {
        grid-template-columns: 200px 1fr; /* Drop the right sidebar (EEAT) */
        gap: 1.5rem;
    }
    
    .sidebar-right {
        display: none; /* Hide right sidebar or stack its components */
    }
    
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 2rem;
    }
}

/* Small Devices (Phones, max-width: 768px) */
@media (max-width: 768px) {
    body {
        padding-top: 60px;
        --header-height: 60px;
    }

    .main-layout {
        grid-template-columns: 1fr; /* Stack everything in single column */
        gap: 1.5rem;
        padding-top: 1.5rem;
    }
    
    .sidebar-left {
        display: none; /* Hide left sidebar TOC - can be implemented as details/summary */
    }
    
    .content-area {
        padding: 1.5rem;
        border-radius: var(--radius-md);
    }
    
    .hero {
        padding: 3rem 0;
    }
    
    .hero h1 {
        font-size: 1.85rem;
    }
    
    .hero p {
        font-size: 1rem;
        margin: 1rem auto 1.75rem;
    }
    
    /* Navigation Adjustments */
    .nav-menu {
        display: none; /* Hide top nav links */
    }
    
    .btn-menu-toggle {
        display: flex; /* Show menu toggle */
    }
    
    /* Toggle functionality classes (handled by client script) */
    .mobile-menu-active .mobile-nav {
        display: flex;
    }
    
    .mobile-menu-active .btn-menu-toggle span:nth-child(1) {
        transform: translateY(7px) rotate(45deg);
    }
    
    .mobile-menu-active .btn-menu-toggle span:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-menu-active .btn-menu-toggle span:nth-child(3) {
        transform: translateY(-7px) rotate(-45deg);
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .contact-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}