Button element highlighting issue while on focus

`Login` Button highlights / changes bg colour to show that its in focus only after you focus in and focus out of it. Ideally it should happen right when it is in focus.

Start by locating the Login button in the client and reproduce the focus interaction. Inspect the button's focus styling and verify that the background highlight appears immediately when it receives focus, without requiring focus-out.

由索引模型根据 Issue 内容生成。