fix: ACG text color

[Domiii]

• [x] Dark text is barely readable, and the white text should probably not be white:
• [x] Reconsider coloring scheme. The ACG in the paper (and in general in screenshotMode) looks too washed out

• [x] Make sure, we maximize contrast. If background is bright, text color should probably be 0 or very close to it. Also make sure, that the color is the same everywhere. It currently seems inconsistent. I searched for " color:" in styles.css (ignore highlight coloring, which is currently disabled):

  .loc-label {
  /* color: #333; */
  white-space: nowrap;
  color: rgba(0, 0, 0);
  }
  
  /* ... */
  
  .theme-mode-dark .loc-label {
  color: #222;
  }
  
  /* ... */
  .theme-mode-dark .research-mode .async-node {
  color: #333;
  }