:root [data-md-color-scheme="default"] {
  /* This shifts the top bar background to your preferred blue */
  --md-primary-fg-color: #1f77b4;
  --md-primary-fg-color--dark: #165683;
}

:root [data-md-color-scheme="slate"] {
  /* Keeps it consistent if you switch to dark/slate mode */
  --md-primary-fg-color: #1f77b4;
}