Dialog button focus is not visible enough in High Contrast mode

[jswiderski]

📝 Provide detailed reproduction steps (if any)

1. Switch your screen to High Contrast (HC) Mode in white color.
2. Open https://ckeditor.com/docs/ckeditor4/latest/examples/fullpreset.html
3. Open link dialog and start tabbing through fields until you reach Ok/Cancel button

✔️ Expected result

When Ok or Cancel button is focused, the focus should be clearly visible. 

❌ Actual result

Focus is really subtle and could be missed by visually impaired users. 

❓ Possible solution

File ckeditor/skins/moono-lisa/dialog.css contains the following CSS rule:

.cke_hc a.cke_dialog_ui_button {
    border: 3px solid #bcbcbc;
}

If you change 3px to 1px, it should  become visible enough.

📃 Other details

• Browser: Any
• OS: Windows
• First affected CKEditor version: 4.6
• Installed CKEditor plugins: N/A

---

If you'd like to see this fixed sooner, add a 👍 reaction to this post.

[mlewand]

@jswiderski I moved the issue to CKE4 repository.

[CKEditorBot]

Closed in #4933