Style file browser buttons

Author: jtpio

packages/tree-extension/style/base.css

@@ -0,0 +1,12 @@
+.jp-FileBrowser-toolbar .jp-Toolbar-item.jp-DropdownMenu,
+.jp-FileBrowser-toolbar .jp-Toolbar-item.jp-ToolbarButton,
+.jp-FileBrowser-toolbar .jp-Toolbar-item.jp-CommandToolbarButton
+{
+  border: solid 1px var(--jp-border-color2);
+  margin: 1px;
+  padding: 0px;
+}
+
+.jp-FileBrowser-toolbar button.jp-ToolbarButtonComponent {
+  height: 100%;
+}

packages/tree-extension/style/index.css

@@ -1,3 +1,5 @@
 @import url('~@jupyterlab/filebrowser/style/index.css');
 
 @import url('~@jupyter-notebook/tree/style/index.css');
+
+@import url('./base.css');

packages/tree-extension/style/index.js

@@ -1,3 +1,5 @@
 import '@jupyterlab/filebrowser/style/index.js';
 
 import '@jupyter-notebook/tree/style/index.js';
+
+import './base.css';