h1
  {
    font-family: Arial, Helvetica, sans-serif;
    color: #ffffff;
    text-align: center;
    margin-top: 20px;
    font-size: 20px;
    position: relative;
  }
  h3 {
    font-family: arial;
    color: #ffffff;
    text-align: left;
    margin-top: 20px;
  }
  body {
      background: linear-gradient(blue, rgb(255, 0, 255));
  }
  .waterfall {
    position: static;
    top: 30%;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
  }
  nav {
    position:sticky;
    top: 0;
    left: 0;
    width: 100%;
    height: 50px;
    background-color: #000000;
    text-align: left;
    line-height: 50px;
    color: #000000;
  }
  .overlay-text {
      position: absolute;
      top: 50%;
    left: 50%;
      transform: translate(-50%, -50%);
      text-align: center;
      font-size: 24px;
      color: white;
  }
  .back-to-top {
      position: fixed;
      bottom: 20px;
      right: 20px;
      color:yellow
  }
  footer {
      position: relative;
  }
  h2 {
      position: relative;
      color: #ffffff;
      text-align: center;
      margin-top: 20px;
  }