@jupyter-lsp/jupyterlab-lsp/style/variables/jupyterlab-dark.css

Language Server Protocol integration for JupyterLab

body[data-jp-theme-light='false'] .cm-s-jupyter {
  --jp-editor-mirror-lsp-highlight-background-color: rgba(151, 173, 255, 0.3);
}

body[data-jp-theme-light='false'] {
  --jp-lsp-signature-mark-color: white;
  --jp-lsp-signature-mark-background: #607e01;
}