diff --git a/packages/jupyterlab-lsp/src/components/free_tooltip.ts b/packages/jupyterlab-lsp/src/components/free_tooltip.ts
index c3646e2e1..09a382f51 100644
--- a/packages/jupyterlab-lsp/src/components/free_tooltip.ts
+++ b/packages/jupyterlab-lsp/src/components/free_tooltip.ts
@@ -16,6 +16,8 @@ import { IEditorPosition } from '../positioning';
 const MIN_HEIGHT = 20;
 const MAX_HEIGHT = 250;
 
+const CLASS_NAME = 'lsp-tooltip';
+
 interface IFreeTooltipOptions extends Tooltip.IOptions {
   /**
    * Position at which the tooltip should be placed, or null (default) to use the current cursor position.
@@ -171,6 +173,7 @@ export class EditorTooltipManager {
       rendermime: this.rendermime_registry,
       position: PositionConverter.cm_to_ce(position)
     });
+    tooltip.addClass(CLASS_NAME);
     tooltip.addClass(options.className);
     Widget.attach(tooltip, document.body);
     this.currentTooltip = tooltip;
diff --git a/packages/jupyterlab-lsp/style/index.css b/packages/jupyterlab-lsp/style/index.css
index 4b28ab75a..f8c68eca8 100644
--- a/packages/jupyterlab-lsp/style/index.css
+++ b/packages/jupyterlab-lsp/style/index.css
@@ -1,5 +1,6 @@
 @import url('./highlight.css');
-@import url('./hover.css');
+@import url('./tooltip.css');
+@import url('./signature.css');
 
 .lsp-document-locator:hover {
   cursor: pointer;
diff --git a/packages/jupyterlab-lsp/style/signature.css b/packages/jupyterlab-lsp/style/signature.css
new file mode 100644
index 000000000..14b420a89
--- /dev/null
+++ b/packages/jupyterlab-lsp/style/signature.css
@@ -0,0 +1,3 @@
+.lsp-signature-help pre code {
+  font-size: var(--jp-code-font-size);
+}
diff --git a/packages/jupyterlab-lsp/style/hover.css b/packages/jupyterlab-lsp/style/tooltip.css
similarity index 59%
rename from packages/jupyterlab-lsp/style/hover.css
rename to packages/jupyterlab-lsp/style/tooltip.css
index 0c5e8171f..4dd05c3d8 100644
--- a/packages/jupyterlab-lsp/style/hover.css
+++ b/packages/jupyterlab-lsp/style/tooltip.css
@@ -1,9 +1,9 @@
-.lsp-hover .jp-RenderedHTMLCommon {
+.lsp-tooltip .jp-RenderedHTMLCommon {
   /* Reduce the default padding from 20px to 0px */
   padding-right: 0px;
 }
 
-.lsp-hover .jp-RenderedHTMLCommon > *:last-child {
+.lsp-tooltip .jp-RenderedHTMLCommon > *:last-child {
   /* Reduce the default margin */
   margin-bottom: 0;
 }