/* ========================================
   VARIABLES CSS - Palette de couleurs
   ======================================== */
:root {
    /* Couleurs principales */
    --primary-color: #38bdf8;
    --primary-dark: #0284c7;
    --secondary-color: #6d3272;
    --accent-color: #303579;
    
    /* Couleurs de fond */
    --bg-dark: #020617;
    --bg-dark-alt: #0f172a;
    --bg-light: #ffffff;
    --bg-section: rgba(187, 187, 187, 0.568);
    --bg-header: #252525;
    
    /* Couleurs de texte */
    --text-primary: #333;
    --text-secondary: #34495e;
    --text-light: #dadada;
    --text-white: #ffffff;
    
    /* Espacements */
    --spacing-xxs: -25px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Transitions */
    --transition-fast: 0.18s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* ========================================
   RESET & BASE
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-light);
    color: var(--text-primary);
    line-height: 1.9;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ========================================
   HEADER
   ======================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 1100;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 1.5rem;
    padding: var(--spacing-xs) var(--spacing-lg);
    background-color: var(--bg-header);
    background:
        radial-gradient(
            circle at top center,
            rgba(56, 189, 248, 0.15),
            transparent 70%
        ),
        linear-gradient(180deg, var(--bg-dark), var(--bg-dark-alt));
    box-shadow: 0 6px 30px rgba(0, 0, 0, 0.4);
    transition: box-shadow var(--transition-normal);
    flex-wrap: nowrap;
}

.site-header:hover {
    box-shadow: 0 8px 40px rgba(0, 59, 85, 0.4);
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: inherit;
    transition: transform var(--transition-normal);
}

.logo:hover {
    transform: scale(1.05);
}

.logo img {
    height: 75px;
    width: auto;
    filter: drop-shadow(0 6px 18px rgba(109, 50, 114, 0.6));
    transition: filter var(--transition-normal);
}

.logo:hover img {
    filter: drop-shadow(0 8px 24px rgba(56, 189, 248, 0.8));
}

/* ========================================
   NAVIGATION
   ======================================== */
.site-nav {
    background-color: transparent;
    display: flex;
    align-items: center;
}

.global-nav {
    display: flex;
    align-items: center;
}

.global-nav > ul.menu {
    list-style: none;
    display: flex;
    justify-content: flex-start;
    align-items: center;
    margin: 0;
    padding: 0;
    gap: 0;
}

.global-nav li {
    flex: 0;
    text-align: center;
}

.global-nav a {
    display: block;
    color: var(--text-light);
    text-decoration: none;
    padding: 0.75rem 1rem;
    border-radius: 6px;
    white-space: nowrap;
    font-size: 14px;
    font-weight: 600;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.global-nav a::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transform: translateX(-50%);
    transition: width var(--transition-normal);
}

.global-nav a:hover::before {
    width: 80%;
}

.global-nav a:hover {
    background-color: #ffffff20;
    color: var(--text-white);
    transform: translateY(-2px);
}

.has-submenu {
    position: relative;
}

.has-submenu a:hover {
    background-color: transparent;
}

.global-nav .has-submenu > a {
    position: relative;
    padding-right: 0.6rem; 
    padding-left: 1.6rem;
}

.global-nav .has-submenu > a::after {
    content: '▾';
    position: absolute;
    right: auto;
    left: 0.5rem;
    top: 50%;
    transform: translateY(-50%) rotate(-90deg);
    transition: transform var(--transition-fast), color var(--transition-fast);
    font-size: 1rem;
    color: var(--text-white);
    pointer-events: none;
}

.global-nav .has-submenu:hover > a::after,
.global-nav .has-submenu.open > a::after {
    transform: translateY(-50%) rotate(0deg);
}

.global-nav .has-submenu > a.active::after {
    color: #0000003b;
}

/* ========================================
   SOUS-MENU
   ======================================== */
.submenu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background-color: #0a0d1f;
    list-style: none;
    padding: var(--spacing-xs) 0;
    margin: 0;
    min-width: 180px;
    border-radius: 6px;
    z-index: 1000;
    flex-direction: column;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    animation: slideDown var(--transition-normal);
}

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

.has-submenu:hover > .submenu {
    display: block;
    width: 100%;
}

.global-nav .has-submenu:hover > .submenu,
.global-nav .has-submenu.open > .submenu {
    background-color: #212436;
}

.global-nav .has-submenu .submenu li a {
    color: var(--text-light);
}

.global-nav .has-submenu .submenu li a:hover {
    background-color: var(--accent-color);
    color: var(--text-white);
}

/* ========================================
   CONTENU PRINCIPAL
   ======================================== */
main {
    flex: 1;
    padding: var(--spacing-lg) 0;
}

h1 {
    text-align: center;
    margin-top: var(--spacing-xxs);
    margin-bottom: var(--spacing-lg);
    color: #374d63;
    font-size: 2.5rem;
    animation: fadeInDown var(--transition-slow);
    border-bottom: 2px solid #374d63;
    padding-bottom: var(--spacing-sm);
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

h2 {
    text-align: center;
    margin-top: var(--spacing-xxs);
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
    border-bottom: 2px solid #374d63;
    padding-bottom: var(--spacing-sm);
}

section {
    background: var(--bg-section);
    margin: var(--spacing-md) var(--spacing-lg);
    padding: var(--spacing-xl);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

section:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.mermaid {
    display: block;
    text-align: center;
    background-color: #f9f9f9;
    padding: var(--spacing-lg);
    border-radius: 6px;
    border: 1px solid #e0e0e0;
    margin-top: var(--spacing-md);
    overflow-x: auto;
}

.tagline {
    font-size: 1.2rem;
    font-weight: 500;
    color: #555;
    margin-bottom: 1.5rem;
}

.presentation-list {
    list-style: disc inside;
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.8;
    margin-top: var(--spacing-md);
}

#presentation{
    margin-top: 0px;
}

/* ========================================
   FOOTER
   ======================================== */
.site-footer {
    background:
        radial-gradient(
            circle at top center,
            rgba(56, 189, 248, 0.15),
            transparent 70%
        ),
        linear-gradient(180deg, var(--bg-dark), var(--bg-dark-alt));
    color: var(--text-light);
    padding: var(--spacing-lg) var(--spacing-lg);
    margin-top: auto;
    box-shadow: 0 -6px 20px rgba(0, 0, 0, 0.5);
}

.site-footer:hover {
    box-shadow: 0 -8px 15px rgba(0, 59, 85, 0.4);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.footer-section h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
    font-size: 0.85rem;
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--primary-color);
}

.footer-section p {
    line-height: 1.6;
    font-size: 0.85rem;
    color: var(--text-light);
}

.social-links {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xs);
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    background: rgba(56, 189, 248, 0.1);
    border: 2px solid var(--primary-color);
    border-radius: 50%;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1rem;
    transition: all var(--transition-normal);
}

.social-links a:hover {
    background: var(--primary-color);
    color: var(--bg-dark);
    transform: translateY(-3px) scale(1.1);
    box-shadow: 0 5px 15px rgba(56, 189, 248, 0.4);
}

.footer-bottom {
    text-align: center;
    margin-top: var(--spacing-sm);
    padding-top: var(--spacing-sm);
    border-top: 1px solid rgba(56, 189, 248, 0.2);
    color: var(--text-light);
    font-size: 0.9rem;
}

.footer-bottom a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-bottom a:hover {
    color: var(--text-white);
}

/* ========================================
   RESPONSIVE DESIGN
   ======================================== */

/* Tablettes */
@media (max-width: 768px) {
    .site-header {
        flex-direction: column;
        padding: var(--spacing-sm);
        gap: var(--spacing-sm);
    }
    
    .logo img {
        height: 100px;
    }
    
    .global-nav > ul.menu {
        flex-direction: column;
        width: 100%;
    }
    
    .global-nav li {
        width: 100%;
    }
    
    .global-nav a {
        text-align: center;
        padding: var(--spacing-sm);
    }
    
    .submenu {
        position: static;
        display: none;
        box-shadow: none;
        background-color: rgba(10, 13, 31, 0.5);
        margin-top: var(--spacing-lg);
        padding-top: var(--spacing-md);
    
    .has-submenu.open > .submenu {
        display: block;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    section {
        margin: var(--spacing-sm);
        padding: var(--spacing-lg);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
}

/* Mobiles */
@media (max-width: 480px) {
    .logo img {
        height: 80px;
        left: 0;
    }
    
    .global-nav a {
        font-size: 13px;
        padding: 0.6rem 0.8rem;
    }
    
    h1 {
        font-size: 1.5rem;
        margin-top: var(--spacing-sm);
        margin-bottom: var(--spacing-sm);
    }
    
    h2 {
        font-size: 1.2rem;
    }
    
    section {
        padding: var(--spacing-md);
        margin: var(--spacing-xs);
    }
    
    .site-footer {
        padding: var(--spacing-lg) var(--spacing-sm);
    }
    
    .social-links {
        justify-content: center;
    }
}

/* Mode paysage mobile */
@media (max-height: 500px) and (orientation: landscape) {
    .logo img {
        height: 60px;
    }
    
    .site-header {
        padding: var(--spacing-xs) var(--spacing-sm);
    }
}
}