:root {
    --primary-color: #2c3e50;
    --accent-color: #3498db;
    --text-on-image: #ffffff;
    --nav-bg: rgba(255, 255, 255, 0.98);
    --bias-height: 8vh;
}

html { 
    scroll-behavior: smooth; 
    overflow-x: hidden; 
}

body { 
    margin: 0; 
    padding: 0; 
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; 
    background: #000; 
}

* {font-family:roboto;}

/* Décalage du scroll */
[id] {
    scroll-margin-top: 125px;
}

/* --- General --- */
h1 {
    margin: 0;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 2px;
    font-size: 1.5rem;
}
a {color: var(--accent-color); }


/* --- HEADER & NAVIGATION --- */
header {
    background: var(--nav-bg);
    padding: 1rem 0;
    text-align: center;
    position: sticky;
    top: 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 1000;
}

header .logo {height:75px;}

.scrolled {display:hidden;}


/* --- Menu Principal --- */
nav { margin-top: 0.5rem; }


nav a { 
    margin: 0 15px; 
    text-decoration: none; 
    color: var(--primary-color); 
    font-weight: bold; 
    text-transform: uppercase; 
    font-size: 0.85rem;
    transition: color 0.3s;
    display:inline-block;
    white-space:nowrap;
    border-radius:8px;
    padding:3px 8px;
    transition: all 0.5s ease-out allow-discrete;
}

nav a:hover { color: var(--accent-color);background:#00000010; }

#main-nav {
    display: flex;
    justify-content: center;
    position: relative;
}

.nav-item {
    position: relative; 
}

.nav-link {
    display: block;
    padding: 15px 20px;
    text-decoration: none;
    color: inherit;
    font-weight: bold;
}

/* --- Sous-menu (Dropdown) --- */
.dropdown {
    position: absolute;
    top: 100%; /* Juste en dessous du menu */
    left: 50%;
    transform: translateX(-50%);
    background-color: white;
    min-width: 200px;
    box-shadow: 0px 8px 16px rgba(0,0,0,0.8);
    display: none; /* Masqué par défaut */
    flex-direction: column;
    z-index: 1000;
    border-radius: 0 0 5px 5px;
}

.dropdown a {
    padding: 10px 15px;
    text-decoration: none;
    color: #333;
    font-size: 0.9rem;
    text-align: left;
    transition: background 0.2s;
    margin:5px 0px;
}

.dropdown a:hover {
    background-color: #f0f0f0;
}

/* --- Affichage au survol --- */
.nav-item:hover .dropdown {
    display: flex;
}

/* --- Style spécifique pour le scroll (header réduit) --- */
.header-top.scrolled {
    display: none;
}

/* --- STRUCTURE DES SECTIONS --- */
#content-area { 
    display: flex; 
    flex-direction: column; 
}

section {
    min-height: 110vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-on-image);
    text-align: justify;
    margin-top: calc(var(--bias-height) * -1);
    padding:200px 10px;
}



section:first-of-type { margin-top: 0; padding-top:30px; }

.sub {width:75%;padding:10px 5px;margin:10px auto;text-align:center;background:#FFFFFF80;border-radius:8px;text-align:justify;}

section img {max-width:75%;border-radius:5px;display:block;margin: 10px auto;align:center;}


section .biblio {margin:10px auto;width:75%;text-align:left;color:#FFFFFFAA;font-size:80%}

hr {width:75%;color: var(--accent-color)}

.table {display:table;margin:10px auto; border-spacing: 10px;table-layout: fixed;}
.table-row {display:table-row;}
.table-cell {display:table-cell;text-align:center;align:center;}
.table-cell img {max-height:200px!important;max-width:100%!important;margin:5px auto;}

/* ARRIÈRE-PLAN FLOUTÉ */
section::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    filter: blur(10px) brightness(0.5);
    transform: scale(1.1);
    z-index: 1;
}

.content-wrapper { 
    position: relative; 
    z-index: 3; 
    max-width: 1920px; 
    padding: 40px; 
}

h2 { font-size: 3rem; margin-bottom: 1rem; text-transform: uppercase; }

section, p { font-size: 1.2rem; font-weight: 300; }

/* --- GESTION DES BIAIS (EMBOÎTEMENT) --- */
section:nth-of-type(odd) {
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--bias-height)), 0 100%);
    z-index: 2;
}

section:nth-of-type(even) {
    clip-path: polygon(0 var(--bias-height), 100% 0, 100% 100%, 0 calc(100% - var(--bias-height)));
    z-index: 1;
}

section:last-of-type {
    clip-path: polygon(0 var(--bias-height), 100% 0, 100% 100%, 0 100%);
}

/* --- FOOTER --- */
footer { 
    padding: 4rem 2rem; 
    background: var(--primary-color); 
    color: white; 
    text-align: center; 
    position: relative; 
    z-index: 10; 
}

/* Conteneur pour rendre la vidéo responsive */
.video-container {
	display:block;
    position: relative;
    padding-bottom: 56.25%; /* Ratio 16:9 */
    height: 0;
    overflow: hidden;
    max-width: 75%;
    margin: 20px auto;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    z-index: 4; /* S'assure d'être au-dessus du fond flou */
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}