HangoutsChat - How can display button's text is only uppercase the first letter?

Question

I tried to create an interactive message as Google Hangouts Chat spec, but my button's text always uppercase all letter. How can I display uppercase only the first letter?

https://developers.google.com/hangouts/chat/how-tos/cards-onclick

"buttons": [
  {
    "textButton": {
      "text": "Login",
      "onClick": {
        "action": {
          "actionMethodName": "loginMethod",
          "parameters": []
        }
      }
    }
  }
]

Expected: button text Login instead of LOGIN

Answer 1

Currently not possible to do so. Hangouts Chat controls the rendering of the cards, and the UI style (from material.io) is to make the text all caps to help make it distinct from other text on the card.