#progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 4px;
  width: 0%;
  z-index: 9999;

  background: linear-gradient(
    90deg,
    #00f5ff,
    #7b2cff,
    #ff2fd1
  );

  box-shadow:
    0 0 10px #00f5ff,
    0 0 20px #7b2cff;
}