Client Alert Boxes [HELP]

[Ethical]

Hi,

I can't seem to get them to change over so seeking some help doing so,

Here are the current:
https://prnt.sc/qn65j3
https://prnt.sc/qn66s1
https://prnt.sc/qn677d

What style I am looking to change to:
https://prnt.sc/qn68mc - I have the HTML & CSS for this.

Any help would be much appreciated, thanks.

[MentaL]