html, body {
  margin: 0;
  padding: 0;
  background: #181818; 
  overflow: hidden; /* 🔥 das ist der Key */
}

main {
  width: 100vw;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;

  overflow: hidden; 
}

canvas {
  display: block;
}

.sketch-container {
  width: 900px;
  height: 900px;
  position: relative;

  transform-origin: center;
}

#sketch canvas {
  width: 100% !important;
  height: 100% !important;
}

/* p5 canvas */
#sketch {
  width: 100%;
  height: 100%;
  /* position: absolute; */
  z-index: 0;
  top: 0;
}

/* gui position */
#gui {
  position: fixed;   
  top: 20px;
  right: 20px;
  z-index: 1000;

  max-height: 90vh;   
  overflow-y: auto;    
}