body {
  margin: 0;
  height: 100vh;
  font: normal 75% Arial, Helvetica, sans-serif;
}

canvas {
  display: block;
  vertical-align: bottom;
}

/* ---- particles.js container ---- */
#particles-js {
  position: fixed; /* <--- utilise fixed au lieu de absolute */
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  background-color: rgb(0, 0, 0);
  background-image: url("");
  background-repeat: no-repeat;
  background-size: cover;
  background-position: 50% 50%;
  z-index: 0;
}

.content {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    color: white;
    font-size: 1rem;
    margin: 0 10%;
}