/* ============================================
   CSS VARIABLES
============================================ */
:root {
    /* Colors - Light Mode */
    --color-bg: #ffffff;
    --color-bg-alt: #f8f9fa;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-primary: #3b82f6;
    --color-accent: #10b981;
    --color-border: #e5e7eb;

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

    /* Border Radius */
    --border-radius-sm: 0.375rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 1rem;

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

    /* Transitions */
    --transition: all 0.3s ease;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-serif: 'Merriweather', Georgia, serif;
}

/* Dark Mode */
[data-theme="dark"] {
    --color-bg: #111827;
    --color-bg-alt: #1f2937;
    --color-text: #f3f4f6;
    --color-text-light: #9ca3af;
    --color-border: #374151;
}

/* ============================================
   GLOBAL STYLES
============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: var(--transition);
}

/* ============================================
   SECTION LAYOUT
============================================ */
section {
    padding: var(--spacing-3xl) 0;
    transition: var(--transition);
}

/* Alternating section backgrounds */
section:nth-of-type(odd) {
    background-color: var(--color-bg);
}

section:nth-of-type(even) {
    background-color: var(--color-bg-alt);
}

section > div {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ============================================
   TYPOGRAPHY HIERARCHY
============================================ */

/* Section Headers (with numbers) */
section > div > div:first-child {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    position: relative;
}

/* Section Numbers */
section > div > div:first-child span {
    display: inline-block;
    font-family: var(--font-serif);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-primary);
    letter-spacing: 0.2em;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-xs) var(--spacing-md);
    border: 2px solid var(--color-primary);
    border-radius: var(--border-radius-sm);
    background: transparent;
    transition: var(--transition);
}

section > div > div:first-child span:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
}

/* H2 - Main Section Titles */
h2 {
    font-family: var(--font-sans);
    font-size: 2rem;
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

/* H2 spans inherit H2 styles */
h2 span {
    font-family: inherit;
    font-size: inherit;
    font-weight: inherit;
    line-height: inherit;
    color: inherit;
}

/* H3 - Subsection Titles */
h3 {
    font-family: var(--font-sans);
    font-size: 1.5rem;
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-text);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
}

/* H3 spans inherit H3 styles */
h3 span {
    font-family: inherit;
    font-size: inherit;
    font-weight: inherit;
    line-height: inherit;
    color: inherit;
}

/* H4 - Sub-subsection Titles */
h4 {
    font-family: var(--font-sans);
    font-size: 1.125rem;
    font-weight: 600;
    line-height: 1.4;
    color: var(--color-text);
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

/* H4 spans inherit H4 styles */
h4 span {
    font-family: inherit;
    font-size: inherit;
    font-weight: inherit;
    line-height: inherit;
    color: inherit;
}

/* ============================================
   CONTENT STYLES
============================================ */

/* Content wrapper - optimal reading width */
section > div > div:not(:first-child) {
    max-width: 800px;
    margin: 0 auto;
}

/* Paragraphs */
p {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

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

/* Strong text */
strong {
    font-weight: 600;
    color: var(--color-text);
}

/* Emphasis */
em {
    font-style: italic;
    color: var(--color-text-light);
}

/* Lists */
ul, ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

li {
    margin-bottom: var(--spacing-sm);
    font-size: 1.0625rem;
    color: var(--color-text);
}

li:last-child {
    margin-bottom: 0;
}

/* Nested lists */
li ul, li ol {
    margin-top: var(--spacing-sm);
    margin-bottom: 0;
}

/* ============================================
   TESTIMONIALS
============================================ */

/* Testimonial/Quote blocks */
.testimonial {
    position: relative;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.03) 0%, rgba(16, 185, 129, 0.03) 100%);
    border-left: 4px solid var(--color-primary);
    padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-lg);
    margin: var(--spacing-xl) 0;
    border-radius: var(--border-radius-md);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] .testimonial {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.08) 0%, rgba(16, 185, 129, 0.08) 100%);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

/* Quote icon */
.testimonial::before {
    content: '"';
    position: absolute;
    top: var(--spacing-md);
    left: var(--spacing-md);
    font-family: var(--font-serif);
    font-size: 4rem;
    line-height: 1;
    color: var(--color-primary);
    opacity: 0.15;
    font-weight: 700;
}

/* Quote text */
.testimonial > p {
    font-style: italic;
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--color-text);
    position: relative;
    z-index: 1;
    margin-bottom: 0;
}

/* Testimonial with avatar structure */
.testimonial-author {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
}

/* Avatar circle */
.testimonial-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--color-primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
    flex-shrink: 0;
}

/* Author info */
.testimonial-info {
    flex: 1;
}

.testimonial-name {
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}

.testimonial-role {
    font-size: 0.875rem;
    color: var(--color-text-light);
}

/* Callout boxes (with emoji headers) */
section > div > div > div:has(> div:first-child > span) {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05) 0%, rgba(16, 185, 129, 0.05) 100%);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

/* Callout header */
section > div > div > div > div:first-child {
    font-weight: 600;
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

/* ============================================
   KEY DECISIONS CARDS
============================================ */

/* Container for the 4 decision cards */
.decisions-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

/* Individual decision card */
.decision-card {
    background: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    transition: var(--transition);
}

[data-theme="dark"] .decision-card {
    background: var(--color-bg-alt);
}

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

/* Number badge in decision cards */
.decision-number {
    display: inline-flex;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    color: white;
    font-weight: 700;
    font-size: 1.5rem;
    font-family: var(--font-serif);
    border-radius: 50%;
    margin-bottom: var(--spacing-md);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

/* Card title (h4) */
.decision-card h4 {
    margin-top: 0;
    margin-bottom: var(--spacing-sm);
    font-size: 1.125rem;
}

/* Card description */
.decision-card p {
    font-size: 0.9375rem;
    line-height: 1.6;
    margin-bottom: 0;
    color: var(--color-text-light);
}

/* ============================================
   IMPACT CARDS (Section 06)
============================================ */

/* Container for the 4 impact cards */
.impact-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

/* Individual impact card */
.impact-card {
    background: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    transition: var(--transition);
    text-align: center;
}

[data-theme="dark"] .impact-card {
    background: var(--color-bg-alt);
}

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

/* Emoji icon in impact cards */
.impact-icon {
    font-size: 3rem;
    line-height: 1;
    margin-bottom: var(--spacing-md);
    display: block;
}

/* Card title (h3) */
.impact-card h3 {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    font-size: 1.25rem;
    font-weight: 700;
}

/* Card description */
.impact-card p {
    font-size: 0.9375rem;
    line-height: 1.7;
    margin-bottom: 0;
    color: var(--color-text);
    text-align: left;
}

/* ============================================
   RESPONSIVE DESIGN
============================================ */
@media (max-width: 768px) {
    section {
        padding: var(--spacing-2xl) 0;
    }

    section > div {
        padding: 0 var(--spacing-md);
    }

    h2 {
        font-size: 2rem;
    }

    h3 {
        font-size: 1.25rem;
    }

    h4 {
        font-size: 1rem;
    }

    p, li {
        font-size: 1rem;
    }

    /* Key decisions cards - single column on mobile */
    .decisions-grid {
        grid-template-columns: 1fr;
    }

    /* Impact cards - single column on mobile */
    .impact-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    section {
        padding: var(--spacing-xl) 0;
    }

    h2 {
        font-size: 1.75rem;
    }

    h3 {
        font-size: 1.125rem;
    }
}

/* ============================================
   HERO SECTION
============================================ */
header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: calc(var(--spacing-3xl) + 60px) var(--spacing-lg) var(--spacing-3xl);
}

[data-theme="dark"] header {
    background: linear-gradient(135deg, #4c63d2 0%, #5a3d8a 100%);
}

header > div {
    max-width: 900px;
    margin: 0 auto;
}

header > div > div {
    text-align: center;
}

/* Badge */
header > div > div > span {
    display: block;
    color: rgba(255, 255, 255, 0.9);
    font-size: 0.8125rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    margin-bottom: var(--spacing-lg);
}

/* H1 - Hero Title */
header h1 {
    font-family: var(--font-serif);
    font-size: 4rem;
    font-weight: 700;
    line-height: 1.15;
    color: white;
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
}

/* H1 spans (for translations) inherit H1 styles */
header h1 span {
    font-family: inherit;
    font-size: inherit;
    font-weight: inherit;
    line-height: inherit;
    color: inherit;
    letter-spacing: inherit;
}

/* Hero Subtitle */
header > div > div > p {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: var(--spacing-xl);
    font-weight: 400;
}

/* Hero Meta Info */
header > div > div > div {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
    justify-content: center;
    align-items: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.2);
}

header > div > div > div > div {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.8);
}

header > div > div > div > div i {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
}

/* ============================================
   STATS SECTION
============================================ */
.stats-section {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.03) 0%, rgba(16, 185, 129, 0.03) 100%);
    padding: var(--spacing-xl) var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

[data-theme="dark"] .stats-section {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05) 0%, rgba(16, 185, 129, 0.05) 100%);
}

.stats-section > div {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    justify-content: space-around;
    align-items: center;
    gap: var(--spacing-xl);
}

.stats-section > div > div {
    text-align: center;
    flex: 1;
}

.stats-section > div > div span:first-child {
    display: block;
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-xs);
    line-height: 1;
}

.stats-section > div > div span:last-child {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-light);
    line-height: 1.4;
}

/* ============================================
   NAVIGATION
============================================ */
#topNav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-lg);
    z-index: 1000;
    transition: transform 0.3s ease;
}

[data-theme="dark"] #topNav {
    background: rgba(17, 24, 39, 0.95);
}

#topNav.hidden {
    transform: translateY(-100%);
}

#topNav > div {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#topNav a {
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    transition: color 0.2s ease;
}

#topNav a:hover {
    color: var(--color-primary);
}

#topNav > div > div {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

#topNav button {
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    cursor: pointer;
    font-size: 0.875rem;
    color: var(--color-text);
    transition: var(--transition);
}

#topNav button:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* Progress Bar */
#progressBar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-accent) 100%);
    z-index: 1001;
    transition: width 0.1s ease;
    width: 0;
}

/* ============================================
   FOOTER
============================================ */
footer {
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-2xl) var(--spacing-lg);
}

footer > div {
    max-width: 1200px;
    margin: 0 auto;
}

footer > div > div {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-lg);
}

footer a {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-md);
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

footer a:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Back to Top Button */
#backToTop {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    background: var(--color-primary);
    color: white;
    border: none;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
}

#backToTop.visible {
    opacity: 1;
    visibility: visible;
}

#backToTop:hover {
    background: var(--color-accent);
    transform: translateY(-4px);
}

/* ============================================
   RESPONSIVE - HERO
============================================ */
@media (max-width: 768px) {
    header {
        padding: calc(var(--spacing-2xl) + 60px) var(--spacing-md) var(--spacing-2xl);
    }

    header h1 {
        font-size: 2.5rem;
    }

    header > div > div > p {
        font-size: 1.0625rem;
    }

    header > div > div > div {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .stats-section > div {
        flex-direction: column;
        gap: var(--spacing-lg);
    }

    .stats-section > div > div span:first-child {
        font-size: 2rem;
    }

    footer > div > div {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 2rem;
    }

    header span:first-child {
        font-size: 0.75rem;
    }
}

/* ============================================
   UTILITY CLASSES
============================================ */
[data-lang="fr"] {
    display: block;
}

[data-lang="en"] {
    display: none;
}

body[data-current-lang="en"] [data-lang="fr"] {
    display: none;
}

body[data-current-lang="en"] [data-lang="en"] {
    display: block;
}