refactor(editor): basic styles of font and panel (#11290)

* Updated `border-radius` of panel to `8px`.  [BS-2901](https://linear.app/affine-design/issue/BS-2901/meta-info-ui-issue) [BS-2810](https://linear.app/affine-design/issue/BS-2810/toolbarpicker-圆角更新为-8px)
* Refactored basic styles of font and panel.

<img width="549" alt="Screenshot 2025-03-31 at 12 56 36" src="https://github.com/user-attachments/assets/4a827e1e-f802-4251-a563-4a34b891a5e3" />

blocksuite/affine/components/src/toolbar/menu-button.ts

@@ -1,4 +1,4 @@
-import { PANEL_BASE } from '@blocksuite/affine-shared/styles';
+import { panelBaseStyle } from '@blocksuite/affine-shared/styles';
 import {
   type ButtonPopperOptions,
   createButtonPopper,
@@ -117,8 +117,8 @@ export class EditorMenuContent extends LitElement {
       overflow-y: auto;
     }
 
+    ${panelBaseStyle(':host([data-show])')}
     :host([data-show]) {
-      ${PANEL_BASE};
       justify-content: center;
       padding: var(--content-padding, 0 6px);
     }