message: fix(panel): fix machine source text fade color
diff: right: 0;
  bottom: 0;
  margin: auto;
  - background: linear-gradient(90deg, rgba(255,255,255,0) 50%, #fff 90%);
  + background: linear-gradient(90deg, rgba(255,255,255,0) 50%, var(--color-background) 90%);
  pointer-events: none;
  }
  .MachineTrans-Lines-collapse {
  &::after {
  - background: linear-gradient(270deg, rgba(255,255,255,0) 50%, #fff 90%);
  + background: linear-gradient(270deg, rgba(255,255,255,0) 50%, var(--color-background) 90%);
  }
  }
  }
  