html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: #000;
  overflow-x: hidden;
}

/* Make particles fill the REAL mobile viewport */
#particles-js {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;   /* fallback */
  height: 100dvh;  /* modern fix */
  z-index: -1;
}
/* keep particles behind everything */
#particles-js {
  position: fixed;
  inset: 0;
  z-index: -1;
}