body {
    margin: 0;
    font-family: "Segoe UI", Arial, sans-serif;
    color: #2c3e50;
    background: linear-gradient(120deg, #a1c4fd, #c2e9fb, #fef9c3, #ffe5d9);
    background-size: 600% 600%;
    animation: gradientBG 15s ease infinite;
}

/* Animation de fond */
@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* En-tête */
header {
    text-align: center;
    padding: 50px 20px 30px 20px;
}
header h1 {
    font-size: 2.8em;
    color: #1a73e8;
    margin-bottom: 10px;
}
header p {
    font-size: 1.2em;
    color: #333;
}

/* Conteneur principal */
.portfolio-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 50px;
    padding: 40px 20px;
}

/* Chaque bloc de portfolio */
.portfolio-item {
    background: rgba(255, 255, 255, 0.85);
    border-radius: 12px;
    box-shadow: 0 6px 18px rgba(0,0,0,0.1);
    padding: 30px;
    width: 80%;
    max-width: 1000px;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}
.portfolio-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 22px rgba(0,0,0,0.15);
}
.portfolio-item h2 {
    color: #1a73e8;
    margin-bottom: 10px;
}
.portfolio-item p {
    font-size: 1em;
    margin-bottom: 20px;
    color: #444;
}

/* c'est l'encadrer des PDF */
iframe {
    width: 100%;
    height: 600px;
    border-radius: 10px;
    border: none;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

/*  Boutons  */
/* ---------------------------------------------------------------------------------------------------------------------  */
.menu {
  position: absolute;
  top: 20px;
  left: 20px;
  display: flex;
  gap: 12px;
}
.menu .btn {
  padding: 10px 18px;
  background-color: #1a73e8;
  color: white;
  text-decoration: none;
  border-radius: 6px;
  font-weight: bold;
  transition: background 0.3s, transform 0.3s;
}
.menu .btn:hover {
  background-color: #1557b0;
  transform: scale(1.05);
}
/* ---------------------------------------------------------------------------------------------------------------------  */

/* Footer */
footer {
    text-align: center;
    padding: 30px 0;
    background: rgba(255,255,255,0.85);
    font-size: 0.9em;
    color: #333;
}
footer a {
    color: #1a73e8;
    text-decoration: none;
}
footer a:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    iframe {
        height: 450px;
    }
    .portfolio-item {
        width: 95%;
        padding: 20px;
    }
}
/*  Fond SVG style routage  */
/* ---------------------------------------------------------------------------------------------------------------------  */
.background-svg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}
.background-svg svg {
    width: 100%;
    height: 100%;
    opacity: 0.25; 
}
.trace {
    stroke-dasharray: 10 14;
    animation: signalFlow 6s linear infinite;
}
.nodes circle {
    fill: #34a853;
    animation: blinkNode 2.5s infinite alternate;
}
@keyframes signalFlow {
    from { stroke-dashoffset: 0; }
    to { stroke-dashoffset: -300; }
}
@keyframes blinkNode {
    from { opacity: 0.3; r: 3; }
    to { opacity: 1; r: 6; }
}
/* ---------------------------------------------------------------------------------------------------------------------  */